Updated opendkim to be built from source.

Dockerfile

@@ -1,19 +1,99 @@
-FROM ubuntu:22.04
+# Build and runtime stages for OpenDKIM on Ubuntu 16.04
+FROM ubuntu:16.04 AS builder
 
-WORKDIR /opt/opendkim
+ARG DEBIAN_FRONTEND=noninteractive
+ARG OPENDKIM_VERSION=2.10.3
+ARG OPENDKIM_TARBALL=opendkim-${OPENDKIM_VERSION}.tar.gz
+ARG OPENDKIM_URL=https://downloads.sourceforge.net/project/opendkim/${OPENDKIM_TARBALL}
 
-RUN apt update && \
+RUN apt-get update && apt-get install -y --no-install-recommends \
-  apt upgrade -y && \
+    build-essential \
-  apt install -y opendkim inetutils-syslogd curl
+    ca-certificates \
+    wget \
+    tar \
+    gzip \
+    make \
+    autoconf \
+    automake \
+    libtool \
+    pkg-config \
+    libssl-dev \
+    libmilter-dev \
+    libbsd-dev \
+    zlib1g-dev \
+ && rm -rf /var/lib/apt/lists/*
 
-RUN curl -SsfL -o /usr/bin/gomplate "https://github.com/hairyhenderson/gomplate/releases/download/v3.11.5/gomplate_linux-amd64-slim" && \
+WORKDIR /build
-  chmod 755 /usr/bin/gomplate && \
-  mkdir -p /etc/rsyslog.d/ && \
-  touch /etc/rsyslog.d/stdout.conf && \
-  echo "*.*    /dev/stdout" > /etc/rsyslog.d/stdout.conf
 
-COPY entrypoint.sh .
+RUN wget -O ${OPENDKIM_TARBALL} ${OPENDKIM_URL} \
-COPY opendkim.conf.tpl .
+ && tar xzf ${OPENDKIM_TARBALL}
 
-EXPOSE 8892/tcp
+WORKDIR /build/opendkim-${OPENDKIM_VERSION}
-CMD ["/bin/bash", "entrypoint.sh"]
+
+# Basic build:
+# - prefix /usr
+# - config in /etc/opendkim
+# - pid file under /run/opendkim
+RUN ./configure \
+    --prefix=/usr \
+    --sysconfdir=/etc \
+    --localstatedir=/var \
+    --disable-shared \
+    --enable-static
+
+RUN make -j"$(nproc)"
+
+# Install into staging root
+RUN make DESTDIR=/opt/opendkim-dist install
+
+# Collect runtime libs actually needed by installed binaries
+RUN mkdir -p /opt/opendkim-libs \
+ && find /opt/opendkim-dist -type f -executable -exec ldd {} \; \
+    | awk '/=> \// {print $3} /^\// {print $1}' \
+    | sort -u \
+    | xargs -r -I '{}' cp -v --parents '{}' /opt/opendkim-libs
+
+# Pack staged install and copied libs as tarballs to avoid BuildKit COPY-to-/ issues
+RUN cd /opt/opendkim-dist \
+ && tar -cf /opt/opendkim-dist.tar .
+
+RUN cd /opt/opendkim-libs \
+ && tar -cf /opt/opendkim-libs.tar .
+
+# Final runtime image
+FROM ubuntu:16.04
+
+ARG DEBIAN_FRONTEND=noninteractive
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    ca-certificates \
+    ssl-cert \
+    inetutils-syslogd \
+ && rm -rf /var/lib/apt/lists/*
+
+COPY --from=builder /opt/opendkim-dist.tar /tmp/opendkim-dist.tar
+COPY --from=builder /opt/opendkim-libs.tar /tmp/opendkim-libs.tar
+
+RUN tar -C / -xf /tmp/opendkim-dist.tar \
+ && tar -C / -xf /tmp/opendkim-libs.tar \
+ && rm -f /tmp/opendkim-dist.tar /tmp/opendkim-libs.tar
+
+RUN groupadd -f opendkim \
+ && (id -u opendkim >/dev/null 2>&1 || useradd -r -g opendkim -d /var/lib/opendkim -s /usr/sbin/nologin opendkim)
+
+RUN mkdir -p \
+    /etc/opendkim \
+    /etc/opendkim/keys \
+    /run/opendkim \
+    /var/lib/opendkim \
+ && chown -R opendkim:opendkim /etc/opendkim/keys /run/opendkim /var/lib/opendkim
+
+RUN touch /etc/opendkim/KeyTable /etc/opendkim/SigningTable /etc/opendkim/TrustedHosts \
+ && chown opendkim:opendkim /etc/opendkim/KeyTable /etc/opendkim/SigningTable /etc/opendkim/TrustedHosts
+
+COPY entrypoint.sh /usr/local/bin/entrypoint.sh
+RUN chmod +x /usr/local/bin/entrypoint.sh
+
+EXPOSE 8891
+
+ENTRYPOINT ["/usr/local/bin/entrypoint.sh"]

README.md

@@ -4,55 +4,215 @@ docker build --rm -t opendkim:latest .
 ```
 
 # Generating private key
-Before running the private key must be generated using opendkim-keygen or supplied.
+Before running the container, a private key must be generated using `opendkim-genkey` or supplied manually.
-```sh
-# Generate private key.
-opendkim-genkey --bits=2048 --selector=dkim --restrict --verbose
 
-# Getting publickey for DNS record.
+```sh
+# Generate private key and DNS record files.
+opendkim-genkey --bits=2048 --selector=dkim --restrict --verbose --domain=example.com
+
+# Generated files:
+#   dkim.private
+#   dkim.txt
+```
+
+To extract the public key value for a DNS TXT record:
+
+```sh
 cat dkim.txt | tr -d "\"\n\" \t" | sed -r "s/.*\((.*)\).*/\\1\n/"
 ```
 
+Example DNS record name:
+
+```txt
+dkim._domainkey.example.com
+```
+
 # Running the image
 ```sh
-docker run -it --rm --name opendkim -p 8892:8892 -v /path/dkim.private:/opt/opendkim/keys/dkim.private opendkim:latest
+docker run -it --rm \
+  --name opendkim \
+  -p 8892:8892 \
+  -v /path/to/dkim.private:/opt/opendkim/keys/dkim.private:ro \
+  opendkim:latest
+```
+
+Example with custom domain and selector:
+
+```sh
+docker run -it --rm \
+  --name opendkim \
+  -p 8892:8892 \
+  -e OPENDKIM_DOMAIN=example.com \
+  -e OPENDKIM_SELECTOR=mail \
+  -e OPENDKIM_SOCKET="inet:8892@0.0.0.0" \
+  -v /path/to/mail.private:/opt/opendkim/keys/dkim.private:ro \
+  opendkim:latest
 ```
 
 # Environment variables
-These values are default and can be overriden by declaring environment variable with naother value.
+These values are defaults and can be overridden by setting environment variables.
-```sh
-# Attempts to become the specified userid before starting operations. The value is of the form userid[:group].
-OPENDKIM_USERID="opendkim"
 
-# Specifies the socket that should be established by the filter to receive connections.
+```sh
+# Runtime user name.
+OPENDKIM_USER="opendkim"
+
+# Runtime group name.
+OPENDKIM_GROUP="opendkim"
+
+# User and group used by OpenDKIM. Format: user:group
+OPENDKIM_USERID="opendkim:opendkim"
+
+# Socket used by the milter service.
 OPENDKIM_SOCKET="inet:8892@0.0.0.0"
 
-# A set of domains whose mail should be signed by this filter.
+# Domain whose mail should be signed.
 OPENDKIM_DOMAIN="*"
 
-# Gives the location of a PEM-formatted private key to be used for signing all messages. Ignored if a KeyTable is defined.
+# DKIM selector.
-OPENDKIM_KEYFILE="/opt/opendkim/keys/dkim.private"
-
-# Defines the name of the selector to be used when signing messages.
 OPENDKIM_SELECTOR="dkim"
 
-# Selects the canonicalization method(s) to be used when signing messages.
+# Path to private key mounted into the container.
+OPENDKIM_KEYFILE="/opt/opendkim/keys/dkim.private"
+
+# Canonicalization method used when signing.
 OPENDKIM_CANONICALIZATION="relaxed/simple"
 
-# Selects operating modes. The string is a concatenation of characters
+# Operating mode:
-# that indicate which mode(s) of operation are desired. Valid modes are s (signer) and v (verifier).
+#   s = signer
+#   v = verifier
+#   sv = sign and verify
 OPENDKIM_MODE="sv"
 
-# Sign subdomains of those listed by the Domain parameter as well as the actual domains.
+# Whether to sign subdomains too.
 OPENDKIM_SUBDOMAINS="true"
 
-# Specifies a set of header fields that should be included in all signature header lists (the "h=" tag) 
+# Headers to oversign.
-# once more than the number of times they were actually present in the signed message.
 OPENDKIM_OVERSIGNHEADERS="From"
 
-# Specifies a file from which trust anchor data should be read when doing DNS queries and applying the DNSSEC protocol.
+# Optional DNSSEC trust anchor file.
-OPENDKIM_TRUSTANCHORFILE="/usr/share/dns/root.key"
+# Added to config only if the file exists.
+OPENDKIM_TRUSTANCHORFILE=""
 
-# Identifies a set internal hosts whose mail should be signed rather than verified.
+# Internal hosts whose mail should be signed instead of verified.
-OPENDKIM_INTERNALHOSTS="127.0.0.0/8, 192.168.0.0/16, 172.16.0.0/12, 10.0.0.0/8"
+OPENDKIM_INTERNALHOSTS="127.0.0.1,localhost,127.0.0.0/8,192.168.0.0/16,172.16.0.0/12,10.0.0.0/8"
+
+# ExternalIgnoreList value for OpenDKIM.
+OPENDKIM_EXTERNALIGNORELIST="refile:/etc/opendkim/TrustedHosts"
+
+# Path to file used for InternalHosts.
+OPENDKIM_INTERNALHOSTS_FILE="/etc/opendkim/TrustedHosts"
+
+# Path to KeyTable.
+OPENDKIM_KEYTABLE="/etc/opendkim/KeyTable"
+
+# Path to SigningTable.
+OPENDKIM_SIGNINGTABLE="refile:/etc/opendkim/SigningTable"
+
+# PID file path.
+OPENDKIM_PIDFILE="/run/opendkim/opendkim.pid"
+
+# Umask used by OpenDKIM.
+OPENDKIM_UMASK="002"
+
+# Whether OpenDKIM should auto-restart.
+OPENDKIM_AUTO_RESTART="no"
+
+# Auto restart rate.
+OPENDKIM_AUTO_RESTART_RATE="10/1h"
+
+# DNS query timeout in seconds.
+OPENDKIM_DNS_TIMEOUT="5"
+
+# Signing algorithm.
+OPENDKIM_SIGNATURE_ALGORITHM="rsa-sha256"
+
+# Refuse unsafe private key permissions.
+OPENDKIM_REQUIRE_SAFE_KEYS="yes"
+
+# Remove old signatures before signing.
+OPENDKIM_REMOVE_OLD_SIGNATURES="no"
+
+# Add SoftwareHeader.
+OPENDKIM_LOGRESULTS="yes"
+
+# Milter debug level.
+OPENDKIM_MILTER_DEBUG="6"
+
+# Optional custom nameservers.
+OPENDKIM_NAMESERVERS=""
 ```
+
+# Behavior
+At startup the container:
+
+- creates OpenDKIM runtime directories
+- copies the mounted private key to `/var/opendkim/dkim.private`
+- sets secure ownership and permissions on the copied key
+- generates `TrustedHosts`, `KeyTable`, and `SigningTable` if they are empty
+- generates `/etc/opendkim.conf` from environment variables
+- starts OpenDKIM using `/etc/opendkim.conf`
+
+# Generated files
+The entrypoint generates these files automatically:
+
+```txt
+/etc/opendkim.conf
+/etc/opendkim/TrustedHosts
+/etc/opendkim/KeyTable
+/etc/opendkim/SigningTable
+/var/opendkim/dkim.private
+```
+
+# Default generated tables
+For example, with:
+
+```sh
+OPENDKIM_DOMAIN=example.com
+OPENDKIM_SELECTOR=dkim
+```
+
+the generated files look like this:
+
+## /etc/opendkim/KeyTable
+```txt
+dkim._domainkey.example.com example.com:dkim:/var/opendkim/dkim.private
+```
+
+## /etc/opendkim/SigningTable
+```txt
+*@example.com dkim._domainkey.example.com
+```
+
+## /etc/opendkim/TrustedHosts
+```txt
+127.0.0.1
+localhost
+127.0.0.0/8
+192.168.0.0/16
+172.16.0.0/12
+10.0.0.0/8
+```
+
+# Postfix example
+Example Postfix settings when OpenDKIM runs in another container named `opendkim`:
+
+```conf
+smtpd_milters = inet:opendkim:8892
+non_smtpd_milters = inet:opendkim:8892
+milter_protocol = 6
+milter_default_action = accept
+```
+
+# Notes
+- The private key must be mounted into the container at the path specified by `OPENDKIM_KEYFILE`.
+- The entrypoint copies the private key to `/var/opendkim/dkim.private` and locks down permissions to `0600`.
+- `OPENDKIM_TRUSTANCHORFILE` is optional and is only written to config if the file exists.
+- `OPENDKIM_NAMESERVERS` is optional and is only written to config if non-empty.
+- `OPENDKIM_DOMAIN="*"` is allowed by the script, but for real signing setups you usually want a concrete domain such as `example.com`.
+- The default socket is `inet:8892@0.0.0.0`, so map port `8892` unless you override `OPENDKIM_SOCKET`.
+- The current entrypoint starts OpenDKIM with:
+  ```sh
+  ./usr/sbin/opendkim -x /etc/opendkim.conf
+  syslogd -n -f /etc/rsyslog.d/stdout.conf
+  ```
+  so the image expects syslog configuration to be present.

entrypoint.sh

@@ -1,25 +1,125 @@
 #!/bin/bash
 
-# Misc default variables.
+# Core defaults.
-export OPENDKIM_USERID=${OPENDKIM_USERID:-opendkim}
+: "${OPENDKIM_USER:=opendkim}"
-export OPENDKIM_SOCKET=${OPENDKIM_SOCKET:-inet:8892@0.0.0.0}
+: "${OPENDKIM_GROUP:=opendkim}"
-export OPENDKIM_DOMAIN=${OPENDKIM_DOMAIN:-*}
+: "${OPENDKIM_USERID:=${OPENDKIM_USER}:${OPENDKIM_GROUP}}"
-export OPENDKIM_KEYFILE=${OPENDKIM_KEYFILE:-/opt/opendkim/keys/dkim.private}
+: "${OPENDKIM_SOCKET:=inet:8892@0.0.0.0}"
-export OPENDKIM_SELECTOR=${OPENDKIM_SELECTOR:-dkim}
-export OPENDKIM_CANONICALIZATION=${OPENDKIM_CANONICALIZATION:-relaxed/simple}
-export OPENDKIM_MODE=${OPENDKIM_MODE:-sv}
-export OPENDKIM_SUBDOMAINS=${OPENDKIM_SUBDOMAINS:-true}
-export OPENDKIM_OVERSIGNHEADERS=${OPENDKIM_OVERSIGNHEADERS:-From}
-export OPENDKIM_TRUSTANCHORFILE=${OPENDKIM_TRUSTANCHORFILE:-/usr/share/dns/root.key}
-export OPENDKIM_INTERNALHOSTS=${OPENDKIM_INTERNALHOSTS:-127.0.0.0/8, 192.168.0.0/16, 172.16.0.0/12, 10.0.0.0/8}
 
-# Configuration templates.
+# Signing defaults.
-gomplate -f opendkim.conf.tpl > /opt/opendkim/opendkim.conf
+: "${OPENDKIM_DOMAIN:=*}"
+: "${OPENDKIM_SELECTOR:=dkim}"
+: "${OPENDKIM_KEYFILE:=/opt/opendkim/keys/dkim.private}"
+: "${OPENDKIM_CANONICALIZATION:=relaxed/simple}"
+: "${OPENDKIM_MODE:=sv}"
+: "${OPENDKIM_SUBDOMAINS:=true}"
+: "${OPENDKIM_OVERSIGNHEADERS:=From}"
 
-mkdir -p /var/opendkim
+# DNS / trust defaults.
-cp $OPENDKIM_KEYFILE /var/opendkim/dkim.private
+: "${OPENDKIM_TRUSTANCHORFILE:=}"
-chown opendkim:opendkim /var/opendkim/dkim.private
+: "${OPENDKIM_INTERNALHOSTS:=127.0.0.1,localhost,127.0.0.0/8,192.168.0.0/16,172.16.0.0/12,10.0.0.0/8}"
+: "${OPENDKIM_EXTERNALIGNORELIST:=refile:/etc/opendkim/TrustedHosts}"
+: "${OPENDKIM_INTERNALHOSTS_FILE:=/etc/opendkim/TrustedHosts}"
+
+# Table files.
+: "${OPENDKIM_KEYTABLE:=/etc/opendkim/KeyTable}"
+: "${OPENDKIM_SIGNINGTABLE:=refile:/etc/opendkim/SigningTable}"
+: "${OPENDKIM_PIDFILE:=/run/opendkim/opendkim.pid}"
+
+# Behavior.
+: "${OPENDKIM_UMASK:=002}"
+: "${OPENDKIM_BACKGROUND:=no}"
+: "${OPENDKIM_AUTO_RESTART:=no}"
+: "${OPENDKIM_AUTO_RESTART_RATE:=10/1h}"
+: "${OPENDKIM_DNS_TIMEOUT:=5}"
+: "${OPENDKIM_SIGNATURE_ALGORITHM:=rsa-sha256}"
+
+# Optional extras.
+: "${OPENDKIM_REQUIRE_SAFE_KEYS:=yes}"
+: "${OPENDKIM_REMOVE_OLD_SIGNATURES:=no}"
+: "${OPENDKIM_LOGRESULTS:=yes}"
+: "${OPENDKIM_MILTER_DEBUG:=6}"
+: "${OPENDKIM_NAMESERVERS:=}"
+
+mkdir -p \
+  /etc/opendkim \
+  /run/opendkim \
+  /var/lib/opendkim \
+  /var/opendkim
+
+touch /etc/opendkim/TrustedHosts /etc/opendkim/KeyTable /etc/opendkim/SigningTable
+
+chown -R "${OPENDKIM_USER}:${OPENDKIM_GROUP}" /run/opendkim /var/lib/opendkim /var/opendkim
+chmod 0755 /run/opendkim /var/lib/opendkim /var/opendkim
+
+# Copy private key to runtime location with safe permissions.
+if [ -f "${OPENDKIM_KEYFILE}" ]; then
+  cp "${OPENDKIM_KEYFILE}" /var/opendkim/dkim.private
+  chown "${OPENDKIM_USER}:${OPENDKIM_GROUP}" /var/opendkim/dkim.private
   chmod 0600 /var/opendkim/dkim.private
+fi
 
-opendkim -x /opt/opendkim/opendkim.conf
+# Generate TrustedHosts from env if file is empty.
+if [ ! -s /etc/opendkim/TrustedHosts ]; then
+  printf '%s\n' "${OPENDKIM_INTERNALHOSTS}" | tr ',' '\n' > /etc/opendkim/TrustedHosts
+fi
+
+# Generate KeyTable from env if file is empty.
+if [ ! -s /etc/opendkim/KeyTable ]; then
+  printf '%s._domainkey.%s %s:%s:/var/opendkim/dkim.private\n' \
+    "${OPENDKIM_SELECTOR}" \
+    "${OPENDKIM_DOMAIN}" \
+    "${OPENDKIM_DOMAIN}" \
+    "${OPENDKIM_SELECTOR}" \
+    > /etc/opendkim/KeyTable
+fi
+
+# Generate SigningTable from env if file is empty.
+if [ ! -s /etc/opendkim/SigningTable ]; then
+  printf '*@%s %s._domainkey.%s\n' \
+    "${OPENDKIM_DOMAIN}" \
+    "${OPENDKIM_SELECTOR}" \
+    "${OPENDKIM_DOMAIN}" \
+    > /etc/opendkim/SigningTable
+fi
+
+chown "${OPENDKIM_USER}:${OPENDKIM_GROUP}" /etc/opendkim/TrustedHosts /etc/opendkim/KeyTable /etc/opendkim/SigningTable
+
+cat > /etc/opendkim.conf <<EOF
+Syslog                  yes
+LogWhy                  yes
+UMask                   ${OPENDKIM_UMASK}
+Canonicalization        ${OPENDKIM_CANONICALIZATION}
+Mode                    ${OPENDKIM_MODE}
+SubDomains              ${OPENDKIM_SUBDOMAINS}
+OversignHeaders         ${OPENDKIM_OVERSIGNHEADERS}
+UserID                  ${OPENDKIM_USERID}
+Socket                  ${OPENDKIM_SOCKET}
+PidFile                 ${OPENDKIM_PIDFILE}
+KeyTable                ${OPENDKIM_KEYTABLE}
+SigningTable            ${OPENDKIM_SIGNINGTABLE}
+ExternalIgnoreList      ${OPENDKIM_EXTERNALIGNORELIST}
+InternalHosts           refile:${OPENDKIM_INTERNALHOSTS_FILE}
+AutoRestart             ${OPENDKIM_AUTO_RESTART}
+AutoRestartRate         ${OPENDKIM_AUTO_RESTART_RATE}
+DNSTimeout              ${OPENDKIM_DNS_TIMEOUT}
+SignatureAlgorithm      ${OPENDKIM_SIGNATURE_ALGORITHM}
+RequireSafeKeys         ${OPENDKIM_REQUIRE_SAFE_KEYS}
+RemoveOldSignatures     ${OPENDKIM_REMOVE_OLD_SIGNATURES}
+MilterDebug             ${OPENDKIM_MILTER_DEBUG}
+EOF
+
+if [ -n "${OPENDKIM_TRUSTANCHORFILE}" ] && [ -f "${OPENDKIM_TRUSTANCHORFILE}" ]; then
+  echo "TrustAnchorFile         ${OPENDKIM_TRUSTANCHORFILE}" >> /etc/opendkim.conf
+fi
+
+if [ "${OPENDKIM_LOGRESULTS}" = "yes" ]; then
+  echo "SoftwareHeader          yes" >> /etc/opendkim.conf
+fi
+
+if [ -n "${OPENDKIM_NAMESERVERS}" ]; then
+  echo "Nameservers             ${OPENDKIM_NAMESERVERS}" >> /etc/opendkim.conf
+fi
+
+./usr/sbin/opendkim -x /etc/opendkim.conf
 syslogd -n -f /etc/rsyslog.d/stdout.conf

opendkim.conf.tpl

@@ -1,47 +0,0 @@
-# Disable log to syslog because we want to log in stdout.
-Syslog                true
-
-# Log via calls to syslog(3) additional entries indicating successful signing or verification of messages.
-SyslogSuccess         true
-
-# If logging is enabled (see Syslog below), issues very detailed logging about the
-# logic behind the filter’s decision to either sign a message or verify it.
-LogWhy                true
-
-# Specifies the path to a file that should be created at process start containing the process ID.
-PidFile               /var/run/opendkim/opendkim.pid
-
-# Attempts to become the specified userid before starting operations. The value is of the form userid[:group].
-UserID                {{ .Env.OPENDKIM_USERID }}
-
-# Specifies the socket that should be established by the filter to receive connections.
-Socket                {{ .Env.OPENDKIM_SOCKET }}
-
-# A set of domains whose mail should be signed by this filter.
-Domain                {{ .Env.OPENDKIM_DOMAIN }}
-
-# Gives the location of a PEM-formatted private key to be used for signing all messages. Ignored if a KeyTable is defined.
-KeyFile               /var/opendkim/dkim.private
-
-# Defines the name of the selector to be used when signing messages.
-Selector              {{ .Env.OPENDKIM_SELECTOR }}
-
-# Selects the canonicalization method(s) to be used when signing messages.
-Canonicalization      {{ .Env.OPENDKIM_CANONICALIZATION }}
-
-# Selects operating modes. The string is a concatenation of characters
-# that indicate which mode(s) of operation are desired. Valid modes are s (signer) and v (verifier).
-Mode                  {{ .Env.OPENDKIM_MODE }}
-
-# Sign subdomains of those listed by the Domain parameter as well as the actual domains.
-SubDomains            {{ .Env.OPENDKIM_SUBDOMAINS }}
-
-# Specifies a set of header fields that should be included in all signature header lists (the "h=" tag) 
-# once more than the number of times they were actually present in the signed message.
-OversignHeaders       {{ .Env.OPENDKIM_OVERSIGNHEADERS }}
-
-# Specifies a file from which trust anchor data should be read when doing DNS queries and applying the DNSSEC protocol.
-TrustAnchorFile       {{ .Env.OPENDKIM_TRUSTANCHORFILE }}
-
-# Identifies a set internal hosts whose mail should be signed rather than verified.
-InternalHosts {{ .Env.OPENDKIM_INTERNALHOSTS }}