NobMail

diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 00000000..04ba039a
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,20 @@
+# EditorConfig helps developers define and maintain consistent
+# coding styles between different editors and IDEs
+# editorconfig.org
+
+root = true
+
+[*]
+
+# Change these settings to your own preference
+indent_style = space
+indent_size = 2
+
+# We recommend you to keep these unchanged
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[*.md]
+trim_trailing_whitespace = false
diff --git a/.gitignore b/.gitignore
index a50c63aa..4dd71779 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,6 +6,8 @@ data/conf/dovecot/dovecot-master.userdb
 mailcow.conf
 mailcow.conf_backup
 data/conf/nginx/*.active
+data/conf/postfix/sni.map
+data/conf/postfix/sni.map.db
 data/conf/postfix/extra.cf
 data/conf/postfix/sql
 data/conf/postfix/allow_mailcow_local.regexp
@@ -14,6 +16,8 @@ data/conf/nextcloud-*.bak
 data/web/inc/vars.local.inc.php
 data/assets/ssl/*
 .vscode/*
+.idea
+*.iml
 data/web/.well-known/acme-challenge
 data/web/nextcloud*/
 data/conf/rspamd/local.d/*
@@ -26,6 +30,7 @@ data/conf/nginx/*.custom
 data/conf/nginx/*.bak
 data/conf/dovecot/acl_anyone
 data/conf/dovecot/mail_plugins*
+data/conf/dovecot/sni.conf
 data/conf/dovecot/sogo-sso.conf
 data/conf/dovecot/extra.conf
 data/conf/dovecot/shared_namespace.conf
diff --git a/data/Dockerfiles/acme/Dockerfile b/data/Dockerfiles/acme/Dockerfile
index 00710ce2..66645f4c 100644
--- a/data/Dockerfiles/acme/Dockerfile
+++ b/data/Dockerfiles/acme/Dockerfile
@@ -18,6 +18,11 @@ RUN apk upgrade --no-cache \
   && python3 -m pip install acme-tiny
 
 COPY acme.sh /srv/acme.sh
+COPY functions.sh /srv/functions.sh
+COPY obtain-certificate.sh /srv/obtain-certificate.sh
+COPY reload-configurations.sh /srv/reload-configurations.sh
 COPY expand6.sh /srv/expand6.sh
 
+RUN chmod +x /srv/*.sh
+
 CMD ["/sbin/tini", "-g", "--", "/srv/acme.sh"]
diff --git a/data/Dockerfiles/acme/acme.sh b/data/Dockerfiles/acme/acme.sh
index a06ce01c..9efaa92b 100755
--- a/data/Dockerfiles/acme/acme.sh
+++ b/data/Dockerfiles/acme/acme.sh
@@ -2,6 +2,7 @@
 set -o pipefail
 exec 5>&1
 
+source /srv/functions.sh
 # Thanks to https://github.com/cvmiller -> https://github.com/cvmiller/expand6
 source /srv/expand6.sh
 
@@ -15,26 +16,15 @@ if [[ "${SKIP_HTTP_VERIFICATION}" =~ ^([yY][eE][sS]|[yY])+$ ]]; then
   SKIP_HTTP_VERIFICATION=y
 fi
 
-# Request certificate for MAILCOW_HOSTNAME ony
+# Request certificate for MAILCOW_HOSTNAME only
 if [[ "${ONLY_MAILCOW_HOSTNAME}" =~ ^([yY][eE][sS]|[yY])+$ ]]; then
   ONLY_MAILCOW_HOSTNAME=y
 fi
 
-log_f() {
-  if [[ ${2} == "no_nl" ]]; then
-    echo -n "$(date) - ${1}"
-  elif [[ ${2} == "no_date" ]]; then
-    echo "${1}"
-  elif [[ ${2} != "redis_only" ]]; then
-    echo "$(date) - ${1}"
-  fi
-  if [[ ${3} == "b64" ]]; then
-    redis-cli -h redis LPUSH ACME_LOG "{\"time\":\"$(date +%s)\",\"message\":\"base64,$(printf '%s' "${1}")\"}" > /dev/null
-  else
-    redis-cli -h redis LPUSH ACME_LOG "{\"time\":\"$(date +%s)\",\"message\":\"$(printf '%s' "${1}" | \
-      tr '%&;$"[]{}-\r\n' ' ')\"}" > /dev/null
-  fi
-}
+# Request individual certificate for every domain
+if [[ "${ENABLE_SSL_SNI}" =~ ^([yY][eE][sS]|[yY])+$ ]]; then
+  ENABLE_SSL_SNI=y
+fi
 
 if [[ "${SKIP_LETS_ENCRYPT}" =~ ^([yY][eE][sS]|[yY])+$ ]]; then
   log_f "SKIP_LETS_ENCRYPT=y, skipping Let's Encrypt..."
@@ -56,97 +46,21 @@ mkdir -p ${ACME_BASE}/acme
 # Migrate
 [[ -f ${ACME_BASE}/acme/private/privkey.pem ]] && mv ${ACME_BASE}/acme/private/privkey.pem ${ACME_BASE}/acme/key.pem
 [[ -f ${ACME_BASE}/acme/private/account.key ]] && mv ${ACME_BASE}/acme/private/account.key ${ACME_BASE}/acme/account.pem
-
-reload_configurations(){
-  # Reading container IDs
-  # Wrapping as array to ensure trimmed content when calling $NGINX etc.
-  local NGINX=($(curl --silent --insecure https://dockerapi/containers/json | jq -r '.[] | {name: .Config.Labels["com.docker.compose.service"], id: .Id}' | jq -rc 'select( .name | tostring | contains("nginx-mailcow")) | .id' | tr "\n" " "))
-  local DOVECOT=($(curl --silent --insecure https://dockerapi/containers/json | jq -r '.[] | {name: .Config.Labels["com.docker.compose.service"], id: .Id}' | jq -rc 'select( .name | tostring | contains("dovecot-mailcow")) | .id' | tr "\n" " "))
-  local POSTFIX=($(curl --silent --insecure https://dockerapi/containers/json | jq -r '.[] | {name: .Config.Labels["com.docker.compose.service"], id: .Id}' | jq -rc 'select( .name | tostring | contains("postfix-mailcow")) | .id' | tr "\n" " "))
-  # Reloading
-  echo "Reloading Nginx..."
-  NGINX_RELOAD_RET=$(curl -X POST --insecure https://dockerapi/containers/${NGINX}/exec -d '{"cmd":"reload", "task":"nginx"}' --silent -H 'Content-type: application/json' | jq -r .type)
-  [[ ${NGINX_RELOAD_RET} != 'success' ]] && { echo "Could not reload Nginx, restarting container..."; restart_container ${NGINX} ; }
-  echo "Reloading Dovecot..."
-  DOVECOT_RELOAD_RET=$(curl -X POST --insecure https://dockerapi/containers/${DOVECOT}/exec -d '{"cmd":"reload", "task":"dovecot"}' --silent -H 'Content-type: application/json' | jq -r .type)
-  [[ ${DOVECOT_RELOAD_RET} != 'success' ]] && { echo "Could not reload Dovecot, restarting container..."; restart_container ${DOVECOT} ; }
-  echo "Reloading Postfix..."
-  POSTFIX_RELOAD_RET=$(curl -X POST --insecure https://dockerapi/containers/${POSTFIX}/exec -d '{"cmd":"reload", "task":"postfix"}' --silent -H 'Content-type: application/json' | jq -r .type)
-  [[ ${POSTFIX_RELOAD_RET} != 'success' ]] && { echo "Could not reload Postfix, restarting container..."; restart_container ${POSTFIX} ; }
-}
-
-restart_container(){
-  for container in $*; do
-    log_f "Restarting ${container}..." no_nl
-    C_REST_OUT=$(curl -X POST --insecure https://dockerapi/containers/${container}/restart | jq -r '.msg')
-    log_f "${C_REST_OUT}" no_date
-  done
-}
-
-array_diff() {
-  # https://stackoverflow.com/questions/2312762, Alex Offshore
-  eval local ARR1=\(\"\${$2[@]}\"\)
-  eval local ARR2=\(\"\${$3[@]}\"\)
-  local IFS=$'\n'
-  mapfile -t $1 < <(comm -23 <(echo "${ARR1[*]}" | sort) <(echo "${ARR2[*]}" | sort))
-}
-
-verify_hash_match(){
-  CERT_HASH=$(openssl x509 -noout -modulus -in "${1}" | openssl md5)
-  KEY_HASH=$(openssl rsa -noout -modulus -in "${2}" | openssl md5)
-  if [[ ${CERT_HASH} != ${KEY_HASH} ]]; then
-    log_f "Certificate and key hashes do not match!"
-    return 1
-  else
-    log_f "Verified hashes."
-    return 0
+if [[ -f ${ACME_BASE}/acme/key.pem && -f ${ACME_BASE}/acme/cert.pem ]]; then
+  if verify_hash_match ${ACME_BASE}/acme/cert.pem ${ACME_BASE}/acme/key.pem; then
+    log_f "Migrating to SNI folder structure..." no_nl
+    CERT_DOMAIN=($(openssl x509 -noout -text -in ${ACME_BASE}/acme/cert.pem | grep "Subject:" | sed -e 's/\(Subject:\)\|\(CN = \)\|\(CN=\)//g' | sed -e 's/^[[:space:]]*//'))
+    CERT_DOMAINS=(${CERT_DOMAIN} $(openssl x509 -noout -text -in ${ACME_BASE}/acme/cert.pem | grep "DNS:" | sed -e 's/\(DNS:\)\|,//g' | sed "s/${CERT_DOMAIN}//" | sed -e 's/^[[:space:]]*//'))
+    mkdir -p ${ACME_BASE}/${CERT_DOMAIN}
+    mv ${ACME_BASE}/acme/cert.pem ${ACME_BASE}/${CERT_DOMAIN}/cert.pem
+    # key is only copied, not moved, because it is used by all other requests too
+    cp ${ACME_BASE}/acme/key.pem ${ACME_BASE}/${CERT_DOMAIN}/key.pem
+    chmod 600 ${ACME_BASE}/${CERT_DOMAIN}/key.pem
+    echo -n ${CERT_DOMAINS[*]} > ${ACME_BASE}/${CERT_DOMAIN}/domains
+    mv ${ACME_BASE}/acme/acme.csr ${ACME_BASE}/${CERT_DOMAIN}/acme.csr
+    log_f "OK" no_date
   fi
-}
-
-get_ipv4(){
-  local IPV4=
-  local IPV4_SRCS=
-  local TRY=
-  IPV4_SRCS[0]="ip4.mailcow.email"
-  IPV4_SRCS[1]="ip4.korves.net"
-  until [[ ! -z ${IPV4} ]] || [[ ${TRY} -ge 10 ]]; do
-    IPV4=$(curl --connect-timeout 3 -m 10 -L4s ${IPV4_SRCS[$RANDOM % ${#IPV4_SRCS[@]} ]} | grep -E "^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$")
-    [[ ! -z ${TRY} ]] && sleep 1
-    TRY=$((TRY+1))
-  done
-  echo ${IPV4}
-}
-
-get_ipv6(){
-  local IPV6=
-  local IPV6_SRCS=
-  local TRY=
-  IPV6_SRCS[0]="ip6.korves.net"
-  IPV6_SRCS[1]="ip6.mailcow.email"
-  until [[ ! -z ${IPV6} ]] || [[ ${TRY} -ge 10 ]]; do
-    IPV6=$(curl --connect-timeout 3 -m 10 -L6s ${IPV6_SRCS[$RANDOM % ${#IPV6_SRCS[@]} ]} | grep "^\([0-9a-fA-F]\{0,4\}:\)\{1,7\}[0-9a-fA-F]\{0,4\}$")
-    [[ ! -z ${TRY} ]] && sleep 1
-    TRY=$((TRY+1))
-  done
-  echo ${IPV6}
-}
-
-verify_challenge_path(){
-  if [[ ${SKIP_HTTP_VERIFICATION} == "y" ]]; then
-    echo '(skipping check, returning 0)'
-    return 0
-  fi
-  # verify_challenge_path URL 4|6
-  RANDOM_N=${RANDOM}${RANDOM}${RANDOM}
-  echo ${RANDOM_N} > /var/www/acme/${RANDOM_N}
-  if [[ "$(curl --insecure -${2} -L http://${1}/.well-known/acme-challenge/${RANDOM_N} --silent)" == "${RANDOM_N}"  ]]; then
-    rm /var/www/acme/${RANDOM_N}
-    return 0
-  else
-    rm /var/www/acme/${RANDOM_N}
-    return 1
-  fi
-}
+fi
 
 [[ ! -f ${ACME_BASE}/dhparams.pem ]] && cp ${SSL_EXAMPLE}/dhparams.pem ${ACME_BASE}/dhparams.pem
 
@@ -158,15 +72,12 @@ if [[ -f ${ACME_BASE}/cert.pem ]] && [[ -f ${ACME_BASE}/key.pem ]] && [[ $(stat
     exec $(readlink -f "$0")
   fi
 else
-  if [[ -f ${ACME_BASE}/acme/cert.pem ]] && [[ -f ${ACME_BASE}/acme/key.pem ]]; then
-    if verify_hash_match ${ACME_BASE}/acme/cert.pem ${ACME_BASE}/acme/key.pem; then
-      log_f "Restoring previous acme certificate and restarting script..."
-      cp ${ACME_BASE}/acme/cert.pem ${ACME_BASE}/cert.pem
-      cp ${ACME_BASE}/acme/key.pem ${ACME_BASE}/key.pem
-      # Restarting with env var set to trigger a restart,
-      exec env TRIGGER_RESTART=1 $(readlink -f "$0")
-    fi
-  ISSUER="mailcow"
+  if [[ -f ${ACME_BASE}/${MAILCOW_HOSTNAME}/cert.pem ]] && [[ -f ${ACME_BASE}/${MAILCOW_HOSTNAME}/key.pem ]] && verify_hash_match ${ACME_BASE}/${MAILCOW_HOSTNAME}/cert.pem ${ACME_BASE}/${MAILCOW_HOSTNAME}/key.pem; then
+    log_f "Restoring previous acme certificate and restarting script..."
+    cp ${ACME_BASE}/${MAILCOW_HOSTNAME}/cert.pem ${ACME_BASE}/cert.pem
+    cp ${ACME_BASE}/${MAILCOW_HOSTNAME}/key.pem ${ACME_BASE}/key.pem
+    # Restarting with env var set to trigger a restart,
+    exec env TRIGGER_RESTART=1 $(readlink -f "$0")
   else
     log_f "Restoring mailcow snake-oil certificates and restarting script..."
     cp ${SSL_EXAMPLE}/cert.pem ${ACME_BASE}/cert.pem
@@ -174,6 +85,7 @@ else
     exec env TRIGGER_RESTART=1 $(readlink -f "$0")
   fi
 fi
+
 chmod 600 ${ACME_BASE}/key.pem
 
 log_f "Waiting for database... " no_nl
@@ -203,10 +115,10 @@ while true; do
 
   # Re-using previous acme-mailcow account and domain keys
   if [[ ! -f ${ACME_BASE}/acme/key.pem ]]; then
-    log_f "Generating missing domain private key..."
+    log_f "Generating missing domain private rsa key..."
     openssl genrsa 4096 > ${ACME_BASE}/acme/key.pem
   else
-    log_f "Using existing domain key ${ACME_BASE}/acme/key.pem"
+    log_f "Using existing domain rsa key ${ACME_BASE}/acme/key.pem"
   fi
   if [[ ! -f ${ACME_BASE}/acme/account.pem ]]; then
     log_f "Generating missing Lets Encrypt account key..."
@@ -218,25 +130,34 @@ while true; do
   chmod 600 ${ACME_BASE}/acme/key.pem
   chmod 600 ${ACME_BASE}/acme/account.pem
 
+  unset EXISTING_CERTS
+  declare -a EXISTING_CERTS
+  for cert_dir in ${ACME_BASE}/*/ ; do
+    if [[ ! -f ${cert_dir}domains ]] || [[ ! -f ${cert_dir}cert.pem ]] || [[ ! -f ${cert_dir}key.pem ]]; then
+      continue
+    fi
+    EXISTING_CERTS+=("$(basename ${cert_dir})")
+  done
+
   # Cleaning up and init validation arrays
   unset SQL_DOMAIN_ARR
   unset VALIDATED_CONFIG_DOMAINS
   unset ADDITIONAL_VALIDATED_SAN
   unset ADDITIONAL_WC_ARR
   unset ADDITIONAL_SAN_ARR
-  unset SAN_CHANGE
-  unset SAN_ARRAY_NOW
-  unset ORPHANED_SAN
-  unset ADDED_SAN
-  SAN_CHANGE=0
-  declare -a SAN_ARRAY_NOW
-  declare -a ORPHANED_SAN
-  declare -a ADDED_SAN
+  unset CERT_ERRORS
+  unset CERT_CHANGED
+  unset CERT_AMOUNT_CHANGED
+  unset VALIDATED_CERTIFICATES
+  CERT_ERRORS=0
+  CERT_CHANGED=0
+  CERT_AMOUNT_CHANGED=0
   declare -a SQL_DOMAIN_ARR
   declare -a VALIDATED_CONFIG_DOMAINS
   declare -a ADDITIONAL_VALIDATED_SAN
   declare -a ADDITIONAL_WC_ARR
   declare -a ADDITIONAL_SAN_ARR
+  declare -a VALIDATED_CERTIFICATES
   IFS=',' read -r -a TMP_ARR <<< "${ADDITIONAL_SAN}"
   for i in "${TMP_ARR[@]}" ; do
     if [[ "$i" =~ \.\*$ ]]; then
@@ -258,9 +179,9 @@ while true; do
   MH_CAAS=( $(dig CAA ${MH_PARENT_DOMAIN} +short | sed -n 's/\d issue "\(.*\)"/\1/p') )
   if [[ ! -z ${MH_CAAS} ]]; then
     if [[ ${MH_CAAS[@]} =~ "letsencrypt.org" ]]; then
-      echo "Validated CAA for parent domain ${MH_PARENT_DOMAIN}"
+      log_f "Validated CAA for parent domain ${MH_PARENT_DOMAIN}"
     else
-      echo "Skipping ACME validation: Lets Encrypt disallowed for ${MAILCOW_HOSTNAME} by CAA record, retrying in 1h..."
+      log_f "Skipping ACME validation: Lets Encrypt disallowed for ${MAILCOW_HOSTNAME} by CAA record, retrying in 1h..."
       sleep 1h
       exec $(readlink -f "$0")
     fi
@@ -268,84 +189,33 @@ while true; do
 
   #########################################
   # IP and webroot challenge verification #
+  SQL_DOMAINS=$(mysql --socket=/var/run/mysqld/mysqld.sock -u ${DBUSER} -p${DBPASS} ${DBNAME} -e "SELECT domain FROM domain WHERE backupmx=0" -Bs)
+  if [[ ! $? -eq 0 ]]; then
+    log_f "Failed to read SQL domains, retrying in 1 minute..."
+    sleep 1m
+    exec $(readlink -f "$0")
+  fi
   while read domains; do
     SQL_DOMAIN_ARR+=("${domains}")
-  done < <(mysql --socket=/var/run/mysqld/mysqld.sock -u ${DBUSER} -p${DBPASS} ${DBNAME} -e "SELECT domain FROM domain WHERE backupmx=0" -Bs)
+  done <<< "${SQL_DOMAINS}"
 
   if [[ ${ONLY_MAILCOW_HOSTNAME} != "y" ]]; then
   for SQL_DOMAIN in "${SQL_DOMAIN_ARR[@]}"; do
+    unset VALIDATED_CONFIG_DOMAINS_SUBDOMAINS
+    declare -a VALIDATED_CONFIG_DOMAINS_SUBDOMAINS
     for SUBDOMAIN in "${ADDITIONAL_WC_ARR[@]}"; do
-      if [[ "${SUBDOMAIN}.${SQL_DOMAIN}" != "${MAILCOW_HOSTNAME}" ]]; then
-        A_SUBDOMAIN=$(dig A ${SUBDOMAIN}.${SQL_DOMAIN} +short | tail -n 1)
-        AAAA_SUBDOMAIN=$(dig AAAA ${SUBDOMAIN}.${SQL_DOMAIN} +short | tail -n 1)
-        # Check if CNAME without v6 enabled target
-        if [[ ! -z ${AAAA_SUBDOMAIN} ]] && [[ -z $(echo ${AAAA_SUBDOMAIN} | grep "^\([0-9a-fA-F]\{0,4\}:\)\{1,7\}[0-9a-fA-F]\{0,4\}$") ]]; then
-          AAAA_SUBDOMAIN=
-        fi
-        if [[ ! -z ${AAAA_SUBDOMAIN} ]]; then
-          log_f "Found AAAA record for ${SUBDOMAIN}.${SQL_DOMAIN}: ${AAAA_SUBDOMAIN} - skipping A record check"
-          if [[ $(expand ${IPV6:-"0000:0000:0000:0000:0000:0000:0000:0000"}) == $(expand ${AAAA_SUBDOMAIN}) ]] || [[ ${SKIP_IP_CHECK} == "y" ]]; then
-            if verify_challenge_path "${SUBDOMAIN}.${SQL_DOMAIN}" 6; then
-              log_f "Confirmed AAAA record with IP ${AAAA_SUBDOMAIN}, adding SAN"
-              VALIDATED_CONFIG_DOMAINS+=("${SUBDOMAIN}.${SQL_DOMAIN}")
-            else
-              log_f "Confirmed AAAA record with IP ${AAAA_SUBDOMAIN}, but HTTP validation failed"
-            fi
-          else
-            log_f "Cannot match your IP ${IPV6:-NO_IPV6_LINK} against hostname ${SUBDOMAIN}.${SQL_DOMAIN} ($(expand ${AAAA_SUBDOMAIN}))"
-          fi
-        elif [[ ! -z ${A_SUBDOMAIN} ]]; then
-          log_f "Found A record for ${SUBDOMAIN}.${SQL_DOMAIN}: ${A_SUBDOMAIN}"
-          if [[ ${IPV4:-ERR} == ${A_SUBDOMAIN} ]] || [[ ${SKIP_IP_CHECK} == "y" ]]; then
-            if verify_challenge_path "${SUBDOMAIN}.${SQL_DOMAIN}" 4; then
-              log_f "Confirmed A record ${A_SUBDOMAIN}, adding SAN"
-              VALIDATED_CONFIG_DOMAINS+=("${SUBDOMAIN}.${SQL_DOMAIN}")
-            else
-              log_f "Confirmed A record with IP ${A_SUBDOMAIN}, but HTTP validation failed"
-            fi
-          else
-            log_f "Cannot match your IP ${IPV4} against hostname ${SUBDOMAIN}.${SQL_DOMAIN} (${A_SUBDOMAIN})"
-          fi
-        else
-          log_f "No A or AAAA record found for hostname ${SUBDOMAIN}.${SQL_DOMAIN}"
+      if [[  "${SUBDOMAIN}.${SQL_DOMAIN}" != "${MAILCOW_HOSTNAME}" ]]; then
+        if check_domain "${SUBDOMAIN}.${SQL_DOMAIN}"; then
+          VALIDATED_CONFIG_DOMAINS_SUBDOMAINS+=("${SUBDOMAIN}.${SQL_DOMAIN}")
         fi
       fi
     done
+    VALIDATED_CONFIG_DOMAINS+=("${VALIDATED_CONFIG_DOMAINS_SUBDOMAINS[*]}")
   done
   fi
 
-  A_MAILCOW_HOSTNAME=$(dig A ${MAILCOW_HOSTNAME} +short | tail -n 1)
-  AAAA_MAILCOW_HOSTNAME=$(dig AAAA ${MAILCOW_HOSTNAME} +short | tail -n 1)
-  # Check if CNAME without v6 enabled target
-  if [[ ! -z ${AAAA_MAILCOW_HOSTNAME} ]] && [[ -z $(echo ${AAAA_MAILCOW_HOSTNAME} | grep "^\([0-9a-fA-F]\{0,4\}:\)\{1,7\}[0-9a-fA-F]\{0,4\}$") ]]; then
-    AAAA_MAILCOW_HOSTNAME=
-  fi
-  if [[ ! -z ${AAAA_MAILCOW_HOSTNAME} ]]; then
-    log_f "Found AAAA record for ${MAILCOW_HOSTNAME}: ${AAAA_MAILCOW_HOSTNAME} - skipping A record check"
-    if [[ $(expand ${IPV6:-"0000:0000:0000:0000:0000:0000:0000:0000"}) == $(expand ${AAAA_MAILCOW_HOSTNAME}) ]] || [[ ${SKIP_IP_CHECK} == "y" ]]; then
-      if verify_challenge_path "${MAILCOW_HOSTNAME}" 6; then
-        log_f "Confirmed AAAA record ${AAAA_MAILCOW_HOSTNAME}"
-        VALIDATED_MAILCOW_HOSTNAME=${MAILCOW_HOSTNAME}
-      else
-        log_f "Confirmed AAAA record with IP ${AAAA_MAILCOW_HOSTNAME}, but HTTP validation failed"
-      fi
-    else
-      log_f "Cannot match your IP ${IPV6:-NO_IPV6_LINK} against hostname ${MAILCOW_HOSTNAME} (DNS returned $(expand ${AAAA_MAILCOW_HOSTNAME}))"
-    fi
-  elif [[ ! -z ${A_MAILCOW_HOSTNAME} ]]; then
-    log_f "Found A record for ${MAILCOW_HOSTNAME}: ${A_MAILCOW_HOSTNAME}"
-    if [[ ${IPV4:-ERR} == ${A_MAILCOW_HOSTNAME} ]] || [[ ${SKIP_IP_CHECK} == "y" ]]; then
-      if verify_challenge_path "${MAILCOW_HOSTNAME}" 4; then
-        log_f "Confirmed A record ${A_MAILCOW_HOSTNAME}"
-        VALIDATED_MAILCOW_HOSTNAME=${MAILCOW_HOSTNAME}
-      else
-        log_f "Confirmed A record with IP ${A_MAILCOW_HOSTNAME}, but HTTP validation failed"
-      fi
-    else
-      log_f "Cannot match your IP ${IPV4} against hostname ${MAILCOW_HOSTNAME} (DNS returned ${A_MAILCOW_HOSTNAME})"
-    fi
-  else
-    log_f "No A or AAAA record found for hostname ${MAILCOW_HOSTNAME}"
+  if check_domain ${MAILCOW_HOSTNAME}; then
+    VALIDATED_MAILCOW_HOSTNAME="${MAILCOW_HOSTNAME}"
   fi
 
   if [[ ${ONLY_MAILCOW_HOSTNAME} != "y" ]]; then
@@ -355,149 +225,123 @@ while true; do
     SAN_CAAS=( $(dig CAA ${SAN_PARENT_DOMAIN} +short | sed -n 's/\d issue "\(.*\)"/\1/p') )
     if [[ ! -z ${SAN_CAAS} ]]; then
       if [[ ${SAN_CAAS[@]} =~ "letsencrypt.org" ]]; then
-        echo "Validated CAA for parent domain ${SAN_PARENT_DOMAIN} of ${SAN}"
+        log_f "Validated CAA for parent domain ${SAN_PARENT_DOMAIN} of ${SAN}"
       else
-        echo "Skipping ACME validation for ${SAN}: Lets Encrypt disallowed for ${SAN} by CAA record"
+        log_f "Skipping ACME validation for ${SAN}: Lets Encrypt disallowed for ${SAN} by CAA record"
         continue
       fi
     fi
     if [[ ${SAN} == ${MAILCOW_HOSTNAME} ]]; then
       continue
     fi
-    A_SAN=$(dig A ${SAN} +short | tail -n 1)
-    AAAA_SAN=$(dig AAAA ${SAN} +short | tail -n 1)
-    # Check if CNAME without v6 enabled target
-    if [[ ! -z ${AAAA_SAN} ]] && [[ -z $(echo ${AAAA_SAN} | grep "^\([0-9a-fA-F]\{0,4\}:\)\{1,7\}[0-9a-fA-F]\{0,4\}$") ]]; then
-      AAAA_SAN=
+    if check_domain ${SAN}; then
+      ADDITIONAL_VALIDATED_SAN+=("${SAN}")
     fi
-    if [[ ! -z ${AAAA_SAN} ]]; then
-      log_f "Found AAAA record for ${SAN}: ${AAAA_SAN} - skipping A record check"
-      if [[ $(expand ${IPV6:-"0000:0000:0000:0000:0000:0000:0000:0000"}) == $(expand ${AAAA_SAN}) ]] || [[ ${SKIP_IP_CHECK} == "y" ]]; then
-        if verify_challenge_path "${SAN}" 6; then
-          log_f "Confirmed AAAA record with IP ${AAAA_SAN}"
-          ADDITIONAL_VALIDATED_SAN+=("${SAN}")
-        else
-          log_f "Confirmed AAAA record with IP ${AAAA_SAN}, but HTTP validation failed"
-        fi
-      else
-        log_f "Cannot match your IP ${IPV6:-NO_IPV6_LINK} against hostname ${SAN} (DNS returned $(expand ${AAAA_SAN}))"
-      fi
-    elif [[ ! -z ${A_SAN} ]]; then
-      log_f "Found A record for ${SAN}: ${A_SAN}"
-      if [[ ${IPV4:-ERR} == ${A_SAN} ]] || [[ ${SKIP_IP_CHECK} == "y" ]]; then
-        if verify_challenge_path "${SAN}" 4; then
-          log_f "Confirmed A record ${A_SAN}"
-          ADDITIONAL_VALIDATED_SAN+=("${SAN}")
-        else
-          log_f "Confirmed A record with IP ${A_SAN}, but HTTP validation failed"
-        fi
+  done
+  fi
+
+  # Unique domains for server certificate
+  if [[ ${ENABLE_SSL_SNI} == "y" ]]; then
+    # create certificate for server name and fqdn SANs only
+    SERVER_SAN_VALIDATED=(${VALIDATED_MAILCOW_HOSTNAME} $(echo ${ADDITIONAL_VALIDATED_SAN[*]} | xargs -n1 | sort -u | xargs))
+  else
+    # create certificate for all domains, including all subdomains from other domains [*]
+    SERVER_SAN_VALIDATED=(${VALIDATED_MAILCOW_HOSTNAME} $(echo ${VALIDATED_CONFIG_DOMAINS[*]} ${ADDITIONAL_VALIDATED_SAN[*]} | xargs -n1 | sort -u | xargs))
+  fi
+  if [[ ! -z ${SERVER_SAN_VALIDATED[*]} ]]; then
+    CERT_NAME=${SERVER_SAN_VALIDATED[0]}
+    VALIDATED_CERTIFICATES+=("${CERT_NAME}")
+
+    # obtain server certificate if required
+    DOMAINS=${SERVER_SAN_VALIDATED[@]} /srv/obtain-certificate.sh rsa
+    RETURN="$?"
+    if [[ "$RETURN" == "0" ]]; then # 0 = cert created successfully
+      CERT_AMOUNT_CHANGED=1
+      CERT_CHANGED=1
+    elif [[ "$RETURN" == "1" ]]; then # 1 = cert renewed successfully
+      CERT_CHANGED=1
+    elif [[ "$RETURN" == "2" ]]; then # 2 = cert not due for renewal
+      :
+    else
+      CERT_ERRORS=1
+    fi
+    # copy hostname certificate to default/server certificate
+    cp ${ACME_BASE}/${CERT_NAME}/cert.pem ${ACME_BASE}/cert.pem
+    cp ${ACME_BASE}/${CERT_NAME}/key.pem ${ACME_BASE}/key.pem
+  fi
+
+  # individual certificates for SNI [@]
+  if [[ ${ENABLE_SSL_SNI} == "y" ]]; then
+  for VALIDATED_DOMAINS in "${VALIDATED_CONFIG_DOMAINS[@]}"; do
+    VALIDATED_DOMAINS_ARR=(${VALIDATED_DOMAINS})
+
+    unset VALIDATED_DOMAINS_SORTED
+    declare -a VALIDATED_DOMAINS_SORTED
+    VALIDATED_DOMAINS_SORTED=(${VALIDATED_DOMAINS_ARR[0]} $(echo ${VALIDATED_DOMAINS_ARR[@]:1} | xargs -n1 | sort -u | xargs))
+
+    if [[ ! -z ${VALIDATED_DOMAINS_SORTED[*]} ]]; then
+      CERT_NAME=${VALIDATED_DOMAINS_SORTED[0]}
+      VALIDATED_CERTIFICATES+=("${CERT_NAME}")
+      # obtain certificate if required
+      DOMAINS=${VALIDATED_DOMAINS_SORTED[@]} /srv/obtain-certificate.sh rsa
+      RETURN="$?"
+      if [[ "$RETURN" == "0" ]]; then # 0 = cert created successfully
+        CERT_AMOUNT_CHANGED=1
+        CERT_CHANGED=1
+      elif [[ "$RETURN" == "1" ]]; then # 1 = cert renewed successfully
+        CERT_CHANGED=1
+      elif [[ "$RETURN" == "2" ]]; then # 2 = cert not due for renewal
+        :
       else
-        log_f "Cannot match your IP ${IPV4} against hostname ${SAN} (DNS returned ${A_SAN})"
+        CERT_ERRORS=1
       fi
-    else
-      log_f "No A or AAAA record found for hostname ${SAN}"
     fi
   done
   fi
 
-  # Unique elements
-  ALL_VALIDATED=(${VALIDATED_MAILCOW_HOSTNAME} $(echo ${VALIDATED_CONFIG_DOMAINS[*]} ${ADDITIONAL_VALIDATED_SAN[*]} | xargs -n1 | sort -u | xargs))
-  if [[ -z ${ALL_VALIDATED[*]} ]]; then
-    log_f "Cannot validate hostnames, skipping Let's Encrypt for 1 hour."
+  if [[ -z ${VALIDATED_CERTIFICATES[*]} ]]; then
+    log_f "Cannot validate any hostnames, skipping Let's Encrypt for 1 hour."
     log_f "Use SKIP_LETS_ENCRYPT=y in mailcow.conf to skip it permanently."
     redis-cli -h redis SET ACME_FAIL_TIME "$(date +%s)"
     sleep 1h
     exec $(readlink -f "$0")
   fi
 
-  # Collecting SANs from active certificate
-  SAN_NAMES=$(openssl x509 -noout -text -in ${ACME_BASE}/cert.pem | awk '/X509v3 Subject Alternative Name/ {getline;gsub(/ /, "", $0); print}' | tr -d "DNS:")
-  if [[ ! -z ${SAN_NAMES} ]]; then
-    IFS=',' read -a SAN_ARRAY_NOW <<< ${SAN_NAMES}
-  fi
-
-  # Finding difference in SAN array now vs. SAN array by current configuration
-  array_diff ORPHANED_SAN SAN_ARRAY_NOW ALL_VALIDATED
-  if [[ ! -z ${ORPHANED_SAN[*]} ]]; then
-    log_f "Found orphaned SAN ${ORPHANED_SAN[*]}"
-    SAN_CHANGE=1
-  fi
-  array_diff ADDED_SAN ALL_VALIDATED SAN_ARRAY_NOW
-  if [[ ! -z ${ADDED_SAN[*]} ]]; then
-    log_f "Found new SAN ${ADDED_SAN[*]}"
-    SAN_CHANGE=1
-  fi
-
-  if [[ ${SAN_CHANGE} == 0 ]]; then
-    # Certificate did not change but could be due for renewal (4 weeks)
-    if ! openssl x509 -checkend 2592000 -noout -in ${ACME_BASE}/cert.pem; then
-      log_f "Certificate is due for renewal (< 30 days)"
-    else
-      log_f "Certificate validation done, neither changed nor due for renewal, sleeping for another day."
-      sleep 1d
-      continue
-    fi
+  # find orphaned certificates if no errors occurred
+  if [[ "${CERT_ERRORS}" == "0" ]]; then
+    for EXISTING_CERT in "${EXISTING_CERTS[@]}"; do
+      if [[ ! "`printf '_%s_\n' "${VALIDATED_CERTIFICATES[@]}"`" == *"_${EXISTING_CERT}_"* ]]; then
+        DATE=$(date +%Y-%m-%d_%H_%M_%S)
+        log_f "Found orphaned certificate: ${EXISTING_CERT} - archiving it at ${ACME_BASE}/backups/${EXISTING_CERT}/"
+        BACKUP_DIR=${ACME_BASE}/backups/${EXISTING_CERT}/${DATE}
+        # archive rsa cert and any other files
+        mv ${ACME_BASE}/${EXISTING_CERT} ${BACKUP_DIR}
+        CERT_CHANGED=1
+        CERT_AMOUNT_CHANGED=1
+      fi
+    done
   fi
 
-  DATE=$(date +%Y-%m-%d_%H_%M_%S)
-  log_f "Creating backups in ${ACME_BASE}/backups/${DATE}/ ..."
-  mkdir -p ${ACME_BASE}/backups/${DATE}/
-  [[ -f ${ACME_BASE}/acme/acme.csr ]] && cp ${ACME_BASE}/acme/acme.csr ${ACME_BASE}/backups/${DATE}/
-  [[ -f ${ACME_BASE}/acme/cert.pem ]] && cp ${ACME_BASE}/acme/cert.pem ${ACME_BASE}/backups/${DATE}/
-  [[ -f ${ACME_BASE}/acme/key.pem ]] && cp ${ACME_BASE}/acme/key.pem ${ACME_BASE}/backups/${DATE}/
-  [[ -f ${ACME_BASE}/acme/account.pem ]] && cp ${ACME_BASE}/acme/account.pem ${ACME_BASE}/backups/${DATE}/
-
-  # Generating CSR
-  printf "[SAN]\nsubjectAltName=" > /tmp/_SAN
-  printf "DNS:%s," "${ALL_VALIDATED[@]}" >> /tmp/_SAN
-  sed -i '$s/,$//' /tmp/_SAN
-  openssl req -new -sha256 -key ${ACME_BASE}/acme/key.pem -subj "/" -reqexts SAN -config <(cat /etc/ssl/openssl.cnf /tmp/_SAN) > ${ACME_BASE}/acme/acme.csr
-
-  if [[ "${LE_STAGING}" =~ ^([yY][eE][sS]|[yY])+$ ]]; then
-    log_f "Using Let's Encrypt staging servers"
-    STAGING_PARAMETER='--directory-url https://acme-staging-v02.api.letsencrypt.org/directory'
-  else
-    STAGING_PARAMETER=
+  # reload on new or changed certificates
+  if [[ "${CERT_CHANGED}" == "1" ]]; then
+    CERT_AMOUNT_CHANGED=${CERT_AMOUNT_CHANGED} /srv/reload-configurations.sh
   fi
 
-  # acme-tiny writes info to stderr and ceritifcate to stdout
-  # The redirects will do the following:
-  # - redirect stdout to temp certificate file
-  # - redirect acme-tiny stderr to stdout (logs to variable ACME_RESPONSE)
-  # - tee stderr to get live output and log to dockerd
-
-  ACME_RESPONSE=$(acme-tiny ${STAGING_PARAMETER} \
-    --account-key ${ACME_BASE}/acme/account.pem \
-    --disable-check \
-    --csr ${ACME_BASE}/acme/acme.csr \
-    --acme-dir /var/www/acme/ 2>&1 > /tmp/_cert.pem | tee /dev/fd/5)
-
-  case "$?" in
-    0) # cert requested
-      ACME_RESPONSE_B64=$(echo "${ACME_RESPONSE}" | openssl enc -e -A -base64)
-      log_f "${ACME_RESPONSE_B64}" redis_only b64
-      log_f "Deploying..."
-      # Deploy the new certificate and key
-      # Moving temp cert to acme/cert.pem
-      if verify_hash_match /tmp/_cert.pem ${ACME_BASE}/acme/key.pem; then
-        mv /tmp/_cert.pem ${ACME_BASE}/acme/cert.pem
-        cp ${ACME_BASE}/acme/cert.pem ${ACME_BASE}/cert.pem
-        cp ${ACME_BASE}/acme/key.pem ${ACME_BASE}/key.pem
-        reload_configurations
-        rm /var/www/acme/* 2> /dev/null
-        log_f "Certificate successfully deployed, removing backup, sleeping 1d"
-        sleep 1d
+  case "$CERT_ERRORS" in
+    0) # all successful
+      if [[ "${CERT_CHANGED}" == "1" ]]; then
+        if [[ "${CERT_AMOUNT_CHANGED}" == "1" ]]; then
+          log_f "Certificates successfully requested and renewed where required, sleeping one day"
+        else
+          log_f "Certificates were successfully renewed where required, sleeping for another day."
+        fi
       else
-        log_f "Certificate was successfully requested, but key and certificate have non-matching hashes, ignoring certificate"
-        log_f "Retrying in 30 minutes..."
-        sleep 30m
-        exec $(readlink -f "$0")
+        log_f "Certificates were successfully validated, no changes or renewals required, sleeping for another day."
       fi
+      sleep 1d
       ;;
-    *) # non-zero is non-fun
-      ACME_RESPONSE_B64=$(echo "${ACME_RESPONSE}" | openssl enc -e -A -base64)
-      log_f "${ACME_RESPONSE_B64}" redis_only b64
-      log_f "Retrying in 30 minutes..."
+    *) # non-zero
+      log_f "Some errors occurred, retrying in 30 minutes..."
       redis-cli -h redis SET ACME_FAIL_TIME "$(date +%s)"
       sleep 30m
       exec $(readlink -f "$0")
diff --git a/data/Dockerfiles/acme/functions.sh b/data/Dockerfiles/acme/functions.sh
new file mode 100644
index 00000000..f5510b15
--- /dev/null
+++ b/data/Dockerfiles/acme/functions.sh
@@ -0,0 +1,112 @@
+#!/bin/bash
+
+log_f() {
+  if [[ ${2} == "no_nl" ]]; then
+    echo -n "$(date) - ${1}"
+  elif [[ ${2} == "no_date" ]]; then
+    echo "${1}"
+  elif [[ ${2} != "redis_only" ]]; then
+    echo "$(date) - ${1}"
+  fi
+  if [[ ${3} == "b64" ]]; then
+    redis-cli -h redis LPUSH ACME_LOG "{\"time\":\"$(date +%s)\",\"message\":\"base64,$(printf '%s' "${1}")\"}" > /dev/null
+  else
+    redis-cli -h redis LPUSH ACME_LOG "{\"time\":\"$(date +%s)\",\"message\":\"$(printf '%s' "${1}" | \
+      tr '%&;$"[]{}-\r\n' ' ')\"}" > /dev/null
+  fi
+}
+
+verify_hash_match(){
+  CERT_HASH=$(openssl x509 -in "${1}" -noout -pubkey | openssl md5)
+  KEY_HASH=$(openssl pkey -in "${2}" -pubout | openssl md5)
+  if [[ ${CERT_HASH} != ${KEY_HASH} ]]; then
+    log_f "Certificate and key hashes do not match!"
+    return 1
+  else
+    log_f "Verified hashes."
+    return 0
+  fi
+}
+
+get_ipv4(){
+  local IPV4=
+  local IPV4_SRCS=
+  local TRY=
+  IPV4_SRCS[0]="ip4.mailcow.email"
+  IPV4_SRCS[1]="ip4.korves.net"
+  until [[ ! -z ${IPV4} ]] || [[ ${TRY} -ge 10 ]]; do
+    IPV4=$(curl --connect-timeout 3 -m 10 -L4s ${IPV4_SRCS[$RANDOM % ${#IPV4_SRCS[@]} ]} | grep -E "^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$")
+    [[ ! -z ${TRY} ]] && sleep 1
+    TRY=$((TRY+1))
+  done
+  echo ${IPV4}
+}
+
+get_ipv6(){
+  local IPV6=
+  local IPV6_SRCS=
+  local TRY=
+  IPV6_SRCS[0]="ip6.korves.net"
+  IPV6_SRCS[1]="ip6.mailcow.email"
+  until [[ ! -z ${IPV6} ]] || [[ ${TRY} -ge 10 ]]; do
+    IPV6=$(curl --connect-timeout 3 -m 10 -L6s ${IPV6_SRCS[$RANDOM % ${#IPV6_SRCS[@]} ]} | grep "^\([0-9a-fA-F]\{0,4\}:\)\{1,7\}[0-9a-fA-F]\{0,4\}$")
+    [[ ! -z ${TRY} ]] && sleep 1
+    TRY=$((TRY+1))
+  done
+  echo ${IPV6}
+}
+
+check_domain(){
+    DOMAIN=$1
+    A_DOMAIN=$(dig A ${DOMAIN} +short | tail -n 1)
+    AAAA_DOMAIN=$(dig AAAA ${DOMAIN} +short | tail -n 1)
+    # Check if CNAME without v6 enabled target
+    if [[ ! -z ${AAAA_DOMAIN} ]] && [[ -z $(echo ${AAAA_DOMAIN} | grep "^\([0-9a-fA-F]\{0,4\}:\)\{1,7\}[0-9a-fA-F]\{0,4\}$") ]]; then
+      AAAA_DOMAIN=
+    fi
+    if [[ ! -z ${AAAA_DOMAIN} ]]; then
+      log_f "Found AAAA record for ${DOMAIN}: ${AAAA_DOMAIN} - skipping A record check"
+      if [[ $(expand ${IPV6:-"0000:0000:0000:0000:0000:0000:0000:0000"}) == $(expand ${AAAA_DOMAIN}) ]] || [[ ${SKIP_IP_CHECK} == "y" ]]; then
+        if verify_challenge_path "${DOMAIN}" 6; then
+          log_f "Confirmed AAAA record with IP ${AAAA_DOMAIN}"
+          return 0
+        else
+          log_f "Confirmed AAAA record with IP ${AAAA_DOMAIN}, but HTTP validation failed"
+        fi
+      else
+        log_f "Cannot match your IP ${IPV6:-NO_IPV6_LINK} against hostname ${DOMAIN} (DNS returned $(expand ${AAAA_DOMAIN}))"
+      fi
+    elif [[ ! -z ${A_DOMAIN} ]]; then
+      log_f "Found A record for ${DOMAIN}: ${A_DOMAIN}"
+      if [[ ${IPV4:-ERR} == ${A_DOMAIN} ]] || [[ ${SKIP_IP_CHECK} == "y" ]]; then
+        if verify_challenge_path "${DOMAIN}" 4; then
+          log_f "Confirmed A record ${A_DOMAIN}"
+          return 0
+        else
+          log_f "Confirmed A record with IP ${A_DOMAIN}, but HTTP validation failed"
+        fi
+      else
+        log_f "Cannot match your IP ${IPV4} against hostname ${DOMAIN} (DNS returned ${A_DOMAIN})"
+      fi
+    else
+      log_f "No A or AAAA record found for hostname ${DOMAIN}"
+    fi
+    return 1
+}
+
+verify_challenge_path(){
+  if [[ ${SKIP_HTTP_VERIFICATION} == "y" ]]; then
+    echo '(skipping check, returning 0)'
+    return 0
+  fi
+  # verify_challenge_path URL 4|6
+  RANDOM_N=${RANDOM}${RANDOM}${RANDOM}
+  echo ${RANDOM_N} > /var/www/acme/${RANDOM_N}
+  if [[ "$(curl --insecure -${2} -L http://${1}/.well-known/acme-challenge/${RANDOM_N} --silent)" == "${RANDOM_N}"  ]]; then
+    rm /var/www/acme/${RANDOM_N}
+    return 0
+  else
+    rm /var/www/acme/${RANDOM_N}
+    return 1
+  fi
+}
diff --git a/data/Dockerfiles/acme/obtain-certificate.sh b/data/Dockerfiles/acme/obtain-certificate.sh
new file mode 100644
index 00000000..27070ae9
--- /dev/null
+++ b/data/Dockerfiles/acme/obtain-certificate.sh
@@ -0,0 +1,120 @@
+#!/bin/bash
+
+# Return values / exit codes
+# 0 = cert created successfully
+# 1 = cert renewed successfully
+# 2 = cert not due for renewal
+# * = errors
+
+
+source /srv/functions.sh
+
+CERT_DOMAINS=(${DOMAINS[@]})
+CERT_DOMAIN=${CERT_DOMAINS[0]}
+ACME_BASE=/var/lib/acme
+
+TYPE=${1}
+PREFIX=""
+# only support rsa certificates for now
+if [[ "${TYPE}" != "rsa" ]]; then
+  log_f "Unknown certificate type '${TYPE}' requested"
+  exit 5
+fi
+DOMAINS_FILE=${ACME_BASE}/${CERT_DOMAIN}/domains
+CERT=${ACME_BASE}/${CERT_DOMAIN}/${PREFIX}cert.pem
+SHARED_KEY=${ACME_BASE}/acme/${PREFIX}key.pem  # must already exist
+KEY=${ACME_BASE}/${CERT_DOMAIN}/${PREFIX}key.pem
+CSR=${ACME_BASE}/${CERT_DOMAIN}/${PREFIX}acme.csr
+
+if [[ -z ${CERT_DOMAINS[*]} ]]; then
+  log_f "Missing CERT_DOMAINS to obtain a certificate"
+  exit 3
+fi
+
+if [[ "${LE_STAGING}" =~ ^([yY][eE][sS]|[yY])+$ ]]; then
+  log_f "Using Let's Encrypt staging servers"
+  STAGING_PARAMETER='--directory-url https://acme-staging-v02.api.letsencrypt.org/directory'
+else
+  STAGING_PARAMETER=
+fi
+
+if [[ -f ${DOMAINS_FILE} && "$(cat ${DOMAINS_FILE})" ==  "${CERT_DOMAINS[*]}" ]]; then
+  if [[ ! -f ${CERT} || ! -f "${KEY}" ]]; then
+    log_f "Certificate ${CERT} doesn't exist yet - start obtaining"
+  # Certificate exists and did not change but could be due for renewal (30 days)
+  elif ! openssl x509 -checkend 2592000 -noout -in ${CERT} > /dev/null; then
+    log_f "Certificate ${CERT} is due for renewal (< 30 days) - start renewing"
+  else
+    log_f "Certificate ${CERT} validation done, neither changed nor due for renewal."
+    exit 2
+  fi
+else
+  log_f "Certificate ${CERT} missing or changed domains '${CERT_DOMAINS[*]}' - start obtaining"
+fi
+
+
+# Make backup
+if [[ -f ${CERT} ]]; then
+  DATE=$(date +%Y-%m-%d_%H_%M_%S)
+  BACKUP_DIR=${ACME_BASE}/backups/${CERT_DOMAIN}/${PREFIX}${DATE}
+  log_f "Creating backups in ${BACKUP_DIR} ..."
+  mkdir -p ${BACKUP_DIR}/
+  [[ -f ${DOMAINS_FILE} ]] && cp ${DOMAINS_FILE} ${BACKUP_DIR}/
+  [[ -f ${CERT} ]] && cp ${CERT} ${BACKUP_DIR}/
+  [[ -f ${KEY} ]] && cp ${KEY} ${BACKUP_DIR}/
+  [[ -f ${CSR} ]] && cp ${CSR} ${BACKUP_DIR}/
+fi
+
+mkdir -p ${ACME_BASE}/${CERT_DOMAIN}
+if [[ ! -f ${KEY} ]]; then
+  log_f "Copying shared private key for this certificate..."
+  cp ${SHARED_KEY} ${KEY}
+  chmod 600 ${KEY}
+fi
+
+# Generating CSR
+printf "[SAN]\nsubjectAltName=" > /tmp/_SAN
+printf "DNS:%s," "${CERT_DOMAINS[@]}" >> /tmp/_SAN
+sed -i '$s/,$//' /tmp/_SAN
+openssl req -new -sha256 -key ${KEY} -subj "/" -reqexts SAN -config <(cat /etc/ssl/openssl.cnf /tmp/_SAN) > ${CSR}
+
+# acme-tiny writes info to stderr and ceritifcate to stdout
+# The redirects will do the following:
+# - redirect stdout to temp certificate file
+# - redirect acme-tiny stderr to stdout (logs to variable ACME_RESPONSE)
+# - tee stderr to get live output and log to dockerd
+
+ACME_RESPONSE=$(acme-tiny ${STAGING_PARAMETER} \
+  --account-key ${ACME_BASE}/acme/account.pem \
+  --disable-check \
+  --csr ${CSR} \
+  --acme-dir /var/www/acme/ 2>&1 > /tmp/_cert.pem | tee /dev/fd/5; exit ${PIPESTATUS[0]})
+SUCCESS="$?"
+ACME_RESPONSE_B64=$(echo "${ACME_RESPONSE}" | openssl enc -e -A -base64)
+log_f "${ACME_RESPONSE_B64}" redis_only b64
+case "$SUCCESS" in
+  0) # cert requested
+    log_f "Deploying certificate ${CERT}..."
+    # Deploy the new certificate and key
+    # Moving temp cert to {domain} folder
+    if verify_hash_match /tmp/_cert.pem ${KEY}; then
+      RETURN=0  # certificate created
+      if [[ -f ${CERT} ]]; then
+        RETURN=1  # certificate renewed
+      fi
+      mv -f /tmp/_cert.pem ${CERT}
+      echo -n ${CERT_DOMAINS[*]} > ${DOMAINS_FILE}
+      rm /var/www/acme/* 2> /dev/null
+      log_f "Certificate successfully obtained"
+      exit ${RETURN}
+    else
+      log_f "Certificate was successfully requested, but key and certificate have non-matching hashes, ignoring certificate"
+      exit 4
+    fi
+    ;;
+  *) # non-zero is non-fun
+    log_f "Failed to obtain certificate ${CERT} for domains '${CERT_DOMAINS[*]}'"
+    redis-cli -h redis SET ACME_FAIL_TIME "$(date +%s)"
+    exit 100${SUCCESS}
+    ;;
+esac
diff --git a/data/Dockerfiles/acme/reload-configurations.sh b/data/Dockerfiles/acme/reload-configurations.sh
new file mode 100644
index 00000000..23f7ba3a
--- /dev/null
+++ b/data/Dockerfiles/acme/reload-configurations.sh
@@ -0,0 +1,43 @@
+#!/bin/bash
+
+# Reading container IDs
+# Wrapping as array to ensure trimmed content when calling $NGINX etc.
+NGINX=($(curl --silent --insecure https://dockerapi/containers/json | jq -r '.[] | {name: .Config.Labels["com.docker.compose.service"], id: .Id}' | jq -rc 'select( .name | tostring | contains("nginx-mailcow")) | .id' | tr "\n" " "))
+DOVECOT=($(curl --silent --insecure https://dockerapi/containers/json | jq -r '.[] | {name: .Config.Labels["com.docker.compose.service"], id: .Id}' | jq -rc 'select( .name | tostring | contains("dovecot-mailcow")) | .id' | tr "\n" " "))
+POSTFIX=($(curl --silent --insecure https://dockerapi/containers/json | jq -r '.[] | {name: .Config.Labels["com.docker.compose.service"], id: .Id}' | jq -rc 'select( .name | tostring | contains("postfix-mailcow")) | .id' | tr "\n" " "))
+
+reload_nginx(){
+  echo "Reloading Nginx..."
+  NGINX_RELOAD_RET=$(curl -X POST --insecure https://dockerapi/containers/${NGINX}/exec -d '{"cmd":"reload", "task":"nginx"}' --silent -H 'Content-type: application/json' | jq -r .type)
+  [[ ${NGINX_RELOAD_RET} != 'success' ]] && { echo "Could not reload Nginx, restarting container..."; restart_container ${NGINX} ; }
+}
+
+reload_dovecot(){
+  echo "Reloading Dovecot..."
+  DOVECOT_RELOAD_RET=$(curl -X POST --insecure https://dockerapi/containers/${DOVECOT}/exec -d '{"cmd":"reload", "task":"dovecot"}' --silent -H 'Content-type: application/json' | jq -r .type)
+  [[ ${DOVECOT_RELOAD_RET} != 'success' ]] && { echo "Could not reload Dovecot, restarting container..."; restart_container ${DOVECOT} ; }
+}
+
+reload_postfix(){
+  echo "Reloading Postfix..."
+  POSTFIX_RELOAD_RET=$(curl -X POST --insecure https://dockerapi/containers/${POSTFIX}/exec -d '{"cmd":"reload", "task":"postfix"}' --silent -H 'Content-type: application/json' | jq -r .type)
+  [[ ${POSTFIX_RELOAD_RET} != 'success' ]] && { echo "Could not reload Postfix, restarting container..."; restart_container ${POSTFIX} ; }
+}
+
+restart_container(){
+  for container in $*; do
+    echo "Restarting ${container}..."
+    C_REST_OUT=$(curl -X POST --insecure https://dockerapi/containers/${container}/restart --silent | jq -r '.msg')
+    echo "${C_REST_OUT}"
+  done
+}
+
+if [[ "${CERT_AMOUNT_CHANGED}" == "1" ]]; then
+  restart_container ${NGINX}
+  restart_container ${DOVECOT}
+  restart_container ${POSTFIX}
+else
+  reload_nginx
+  reload_dovecot
+  reload_postfix
+fi
diff --git a/data/Dockerfiles/dovecot/docker-entrypoint.sh b/data/Dockerfiles/dovecot/docker-entrypoint.sh
index 1702bf5a..1aa75891 100755
--- a/data/Dockerfiles/dovecot/docker-entrypoint.sh
+++ b/data/Dockerfiles/dovecot/docker-entrypoint.sh
@@ -142,6 +142,20 @@ if [[ $(stat -c %U /var/attachments) != "vmail" ]] ; then chown -R vmail:vmail /
 # Cleanup random user maildirs
 rm -rf /var/vmail/mailcow.local/*
 
+# create sni configuration
+echo "" > /etc/dovecot/sni.conf
+for cert_dir in /etc/ssl/mail/*/ ; do
+  if [[ ! -f ${cert_dir}domains ]] || [[ ! -f ${cert_dir}cert.pem ]] || [[ ! -f ${cert_dir}key.pem ]]; then
+    continue
+  fi
+  domains=($(cat ${cert_dir}domains))
+  for domain in ${domains[@]}; do
+    echo 'local_name '${domain}' {' >> /etc/dovecot/sni.conf;
+    echo '  ssl_cert = <'${cert_dir}'cert.pem' >> /etc/dovecot/sni.conf;
+    echo '  ssl_key = <'${cert_dir}'key.pem' >> /etc/dovecot/sni.conf;
+    echo '}' >> /etc/dovecot/sni.conf;
+  done
+done
 
 # Create random master for SOGo sieve features
 RAND_USER=$(cat /dev/urandom | tr -dc 'a-z0-9' | fold -w 16 | head -n 1)
diff --git a/data/Dockerfiles/postfix/postfix.sh b/data/Dockerfiles/postfix/postfix.sh
index 3d060e8c..766ed967 100755
--- a/data/Dockerfiles/postfix/postfix.sh
+++ b/data/Dockerfiles/postfix/postfix.sh
@@ -19,6 +19,20 @@ spam: "|/usr/local/bin/rspamd-pipe-spam"
 EOF
 newaliases;
 
+# create sni configuration
+echo -n "" > /opt/postfix/conf/sni.map;
+for cert_dir in /etc/ssl/mail/*/ ; do
+  if [[ ! -f ${cert_dir}domains ]] || [[ ! -f ${cert_dir}cert.pem ]] || [[ ! -f ${cert_dir}key.pem ]]; then
+    continue;
+  fi
+  IFS=" " read -r -a domains <<< "$(cat "${cert_dir}domains")"
+  for domain in "${domains[@]}"; do
+    echo -n "${domain} ${cert_dir}key.pem ${cert_dir}cert.pem" >> /opt/postfix/conf/sni.map;
+    echo "" >> /opt/postfix/conf/sni.map;
+  done
+done
+postmap -F hash:/opt/postfix/conf/sni.map;
+
 cat <<EOF > /opt/postfix/conf/sql/mysql_relay_recipient_maps.cf
 # Autogenerated by mailcow
 user = ${DBUSER}
diff --git a/data/conf/dovecot/dovecot.conf b/data/conf/dovecot/dovecot.conf
index 51e58710..f07c0e19 100644
--- a/data/conf/dovecot/dovecot.conf
+++ b/data/conf/dovecot/dovecot.conf
@@ -272,6 +272,7 @@ service lmtp {
 listen = *,[::]
 ssl_cert = </etc/ssl/mail/cert.pem
 ssl_key = </etc/ssl/mail/key.pem
+!include_try /etc/dovecot/sni.conf
 userdb {
   driver = passwd-file
   args = /etc/dovecot/dovecot-master.userdb
diff --git a/data/conf/nginx/site.conf b/data/conf/nginx/includes/site-defaults.conf
similarity index 92%
rename from data/conf/nginx/site.conf
rename to data/conf/nginx/includes/site-defaults.conf
index fddae9f4..53778020 100644
--- a/data/conf/nginx/site.conf
+++ b/data/conf/nginx/includes/site-defaults.conf
@@ -1,19 +1,8 @@
-server_tokens off;
-proxy_cache_path /tmp levels=1:2 keys_zone=sogo:10m inactive=24h  max_size=1g;
-server_names_hash_bucket_size 64;
 
-map $http_x_forwarded_proto $client_req_scheme {
-     default $scheme;
-     https https;
-}
-
-server {
   include /etc/nginx/mime.types;
   charset utf-8;
   override_charset on;
 
-  ssl_certificate /etc/ssl/mail/cert.pem;
-  ssl_certificate_key /etc/ssl/mail/key.pem;
   ssl_protocols TLSv1.2 TLSv1.3;
   ssl_ciphers 'ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256';
   ssl_prefer_server_ciphers on;
@@ -34,11 +23,6 @@ server {
 
   client_max_body_size 0;
 
-  listen 127.0.0.1:65510;
-  include /etc/nginx/conf.d/listen_plain.active;
-  include /etc/nginx/conf.d/listen_ssl.active;
-  include /etc/nginx/conf.d/server_name.active;
-
   gzip on;
   gzip_disable "msie6";
 
@@ -221,4 +205,3 @@ server {
   location @awaitingupstream {
     rewrite ^(.*)$ /_status.502.html break;
   }
-}
diff --git a/data/conf/nginx/templates/listen_plain.template b/data/conf/nginx/templates/listen_plain.template
deleted file mode 100644
index a044b22f..00000000
--- a/data/conf/nginx/templates/listen_plain.template
+++ /dev/null
@@ -1,2 +0,0 @@
-listen ${HTTP_PORT};
-listen [::]:${HTTP_PORT};
diff --git a/data/conf/nginx/templates/listen_ssl.template b/data/conf/nginx/templates/listen_ssl.template
deleted file mode 100644
index 93ec80c6..00000000
--- a/data/conf/nginx/templates/listen_ssl.template
+++ /dev/null
@@ -1,2 +0,0 @@
-listen ${HTTPS_PORT} ssl http2;
-listen [::]:${HTTPS_PORT} ssl http2;
diff --git a/data/conf/nginx/templates/server_name.template b/data/conf/nginx/templates/server_name.template
deleted file mode 100644
index 261a1ece..00000000
--- a/data/conf/nginx/templates/server_name.template
+++ /dev/null
@@ -1 +0,0 @@
-server_name ${MAILCOW_HOSTNAME} autodiscover.* autoconfig.*;
diff --git a/data/conf/nginx/templates/sites.template.sh b/data/conf/nginx/templates/sites.template.sh
new file mode 100644
index 00000000..b9f58738
--- /dev/null
+++ b/data/conf/nginx/templates/sites.template.sh
@@ -0,0 +1,40 @@
+echo '
+server {
+  listen 127.0.0.1:65510;
+  listen '${HTTP_PORT}' default_server;
+  listen [::]:'${HTTP_PORT}' default_server;
+  listen '${HTTPS_PORT}' ssl http2 default_server;
+  listen [::]:'${HTTPS_PORT}' ssl http2 default_server;
+
+  ssl_certificate /etc/ssl/mail/cert.pem;
+  ssl_certificate_key /etc/ssl/mail/key.pem;
+
+  server_name '${MAILCOW_HOSTNAME}' autodiscover.* autoconfig.*;
+
+  include /etc/nginx/conf.d/includes/site-defaults.conf;
+}
+';
+for cert_dir in /etc/ssl/mail/*/ ; do
+  if [[ ! -f ${cert_dir}domains ]] || [[ ! -f ${cert_dir}cert.pem ]] || [[ ! -f ${cert_dir}key.pem ]]; then
+    continue
+  fi
+  # remove hostname to not cause nginx warnings (hostname is covered in default server listen)
+  domains="$(cat ${cert_dir}domains | sed -e "s/\(^\| \)\($(echo ${MAILCOW_HOSTNAME} | sed 's/\./\\./g')\)\( \|$\)/ /g" | sed -e 's/^[[:space:]]*//')"
+  if [[ "${domains}" == "" ]]; then
+    continue
+  fi
+  echo -n '
+server {
+  listen '${HTTPS_PORT}' ssl http2;
+  listen [::]:'${HTTPS_PORT}' ssl http2;
+
+  ssl_certificate '${cert_dir}'cert.pem;
+  ssl_certificate_key '${cert_dir}'key.pem;
+';
+  echo -n '
+  server_name '${domains}';
+
+  include /etc/nginx/conf.d/includes/site-defaults.conf;
+}
+';
+done
diff --git a/data/conf/postfix/main.cf b/data/conf/postfix/main.cf
index 98e81a34..36fb7d85 100644
--- a/data/conf/postfix/main.cf
+++ b/data/conf/postfix/main.cf
@@ -5,6 +5,7 @@ biff = no
 append_dot_mydomain = no
 smtpd_tls_cert_file = /etc/ssl/mail/cert.pem
 smtpd_tls_key_file = /etc/ssl/mail/key.pem
+tls_server_sni_maps = hash:/opt/postfix/conf/sni.map
 smtpd_use_tls=yes
 smtpd_tls_received_header = yes
 smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
@@ -174,7 +175,7 @@ smtp_address_preference = ipv4
 smtp_sender_dependent_authentication = yes
 smtp_sasl_auth_enable = yes
 smtp_sasl_password_maps = proxy:mysql:/opt/postfix/conf/sql/mysql_sasl_passwd_maps_sender_dependent.cf
-smtp_sasl_security_options = 
+smtp_sasl_security_options =
 smtp_sasl_mechanism_filter = plain, login
 smtp_tls_policy_maps=proxy:mysql:/opt/postfix/conf/sql/mysql_tls_policy_override_maps.cf
 smtp_header_checks = pcre:/opt/postfix/conf/anonymize_headers.pcre
diff --git a/docker-compose.yml b/docker-compose.yml
index 4567bcdf..41e6a514 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -275,12 +275,10 @@ services:
       image: nginx:mainline-alpine
       dns:
         - ${IPV4_NETWORK:-172.22.1}.254
-      command: /bin/sh -c "envsubst < /etc/nginx/conf.d/templates/listen_plain.template > /etc/nginx/conf.d/listen_plain.active &&
-        envsubst < /etc/nginx/conf.d/templates/listen_ssl.template > /etc/nginx/conf.d/listen_ssl.active &&
-        envsubst < /etc/nginx/conf.d/templates/server_name.template > /etc/nginx/conf.d/server_name.active &&
-        envsubst < /etc/nginx/conf.d/templates/sogo.template > /etc/nginx/conf.d/sogo.active &&
+      command: /bin/sh -c "envsubst < /etc/nginx/conf.d/templates/sogo.template > /etc/nginx/conf.d/sogo.active &&
         envsubst < /etc/nginx/conf.d/templates/sogo_eas.template > /etc/nginx/conf.d/sogo_eas.active &&
         . /etc/nginx/conf.d/templates/sogo.auth_request.template.sh > /etc/nginx/conf.d/sogo_proxy_auth.active &&
+        . /etc/nginx/conf.d/templates/sites.template.sh > /etc/nginx/conf.d/sites.active &&
         nginx -qt &&
         until ping phpfpm -c1 > /dev/null; do sleep 1; done &&
         until ping sogo -c1 > /dev/null; do sleep 1; done &&
@@ -325,6 +323,7 @@ services:
         - DBUSER=${DBUSER}
         - DBPASS=${DBPASS}
         - SKIP_LETS_ENCRYPT=${SKIP_LETS_ENCRYPT:-n}
+        - ENABLE_SSL_SNI=${ENABLE_SSL_SNI:-n}
         - SKIP_IP_CHECK=${SKIP_IP_CHECK:-n}
         - SKIP_HTTP_VERIFICATION=${SKIP_HTTP_VERIFICATION:-n}
         - ONLY_MAILCOW_HOSTNAME=${ONLY_MAILCOW_HOSTNAME:-n}