Add SMTP support through VIRTUAL_PROTO=smtp to use nginx-proxy to add LE-cert to mailserver

[jastlw]

Hi @jwilder,

you have closed issue #400 with the same question: may it possible to add an option to use nginx-proxy to proxy SMTP request to nginx?
Do you think the situation has changed and it may now be a good idea?

If I have understand things right, the open "--with-mail" would be needed while compiling nginx.
https://docs.nginx.com/nginx/admin-guide/mail-proxy/mail-proxy/

I would like do also route the traffic to my mail server through nginx-proxy, because I love it. ;)
I understand that it is only possible to have one mail server per IP-address and smtp does not support virtual-host. But I wish just to use one mails server within my nginx-proxy-setup.
docker-mailserver/docker-mailserver#1875 (comment)

Thank you a lot for the nice work until now &
all the best!

Jacob

[buchdag]

Hi Jacob.

Unfortunately features that require custom nginx compilation are out of scope at the moment, because maintaining our own nginx base image rather than relying on the upstream image would be way too heavy for the ressources we have.

Just to give you an idea this is what the current mainline nginx Dockerfile looks like:

Dockerfile

#
# NOTE: THIS DOCKERFILE IS GENERATED VIA "update.sh"
#
# PLEASE DO NOT EDIT IT DIRECTLY.
#
FROM debian:bullseye-slim

LABEL maintainer="NGINX Docker Maintainers <docker-maint@nginx.com>"

ENV NGINX_VERSION   1.25.0
ENV NJS_VERSION     0.7.12
ENV PKG_RELEASE     1~bullseye

RUN set -x \
# create nginx user/group first, to be consistent throughout docker variants
    && addgroup --system --gid 101 nginx \
    && adduser --system --disabled-login --ingroup nginx --no-create-home --home /nonexistent --gecos "nginx user" --shell /bin/false --uid 101 nginx \
    && apt-get update \
    && apt-get install --no-install-recommends --no-install-suggests -y gnupg1 ca-certificates \
    && \
    NGINX_GPGKEY=573BFD6B3D8FBC641079A6ABABF5BD827BD9BF62; \
    NGINX_GPGKEY_PATH=/usr/share/keyrings/nginx-archive-keyring.gpg; \
    export GNUPGHOME="$(mktemp -d)"; \
    found=''; \
    for server in \
        hkp://keyserver.ubuntu.com:80 \
        pgp.mit.edu \
    ; do \
        echo "Fetching GPG key $NGINX_GPGKEY from $server"; \
        gpg1 --keyserver "$server" --keyserver-options timeout=10 --recv-keys "$NGINX_GPGKEY" && found=yes && break; \
    done; \
    test -z "$found" && echo >&2 "error: failed to fetch GPG key $NGINX_GPGKEY" && exit 1; \
    gpg1 --export "$NGINX_GPGKEY" > "$NGINX_GPGKEY_PATH" ; \
    rm -rf "$GNUPGHOME"; \
    apt-get remove --purge --auto-remove -y gnupg1 && rm -rf /var/lib/apt/lists/* \
    && dpkgArch="$(dpkg --print-architecture)" \
    && nginxPackages=" \
        nginx=${NGINX_VERSION}-${PKG_RELEASE} \
        nginx-module-xslt=${NGINX_VERSION}-${PKG_RELEASE} \
        nginx-module-geoip=${NGINX_VERSION}-${PKG_RELEASE} \
        nginx-module-image-filter=${NGINX_VERSION}-${PKG_RELEASE} \
        nginx-module-njs=${NGINX_VERSION}+${NJS_VERSION}-${PKG_RELEASE} \
    " \
    && case "$dpkgArch" in \
        amd64|arm64) \
# arches officialy built by upstream
            echo "deb [signed-by=$NGINX_GPGKEY_PATH] https://nginx.org/packages/mainline/debian/ bullseye nginx" >> /etc/apt/sources.list.d/nginx.list \
            && apt-get update \
            ;; \
        *) \
# we're on an architecture upstream doesn't officially build for
# let's build binaries from the published source packages
            echo "deb-src [signed-by=$NGINX_GPGKEY_PATH] https://nginx.org/packages/mainline/debian/ bullseye nginx" >> /etc/apt/sources.list.d/nginx.list \
            \
# new directory for storing sources and .deb files
            && tempDir="$(mktemp -d)" \
            && chmod 777 "$tempDir" \
# (777 to ensure APT's "_apt" user can access it too)
            \
# save list of currently-installed packages so build dependencies can be cleanly removed later
            && savedAptMark="$(apt-mark showmanual)" \
            \
# build .deb files from upstream's source packages (which are verified by apt-get)
            && apt-get update \
            && apt-get build-dep -y $nginxPackages \
            && ( \
                cd "$tempDir" \
                && DEB_BUILD_OPTIONS="nocheck parallel=$(nproc)" \
                    apt-get source --compile $nginxPackages \
            ) \
# we don't remove APT lists here because they get re-downloaded and removed later
            \
# reset apt-mark's "manual" list so that "purge --auto-remove" will remove all build dependencies
# (which is done after we install the built packages so we don't have to redownload any overlapping dependencies)
            && apt-mark showmanual | xargs apt-mark auto > /dev/null \
            && { [ -z "$savedAptMark" ] || apt-mark manual $savedAptMark; } \
            \
# create a temporary local APT repo to install from (so that dependency resolution can be handled by APT, as it should be)
            && ls -lAFh "$tempDir" \
            && ( cd "$tempDir" && dpkg-scanpackages . > Packages ) \
            && grep '^Package: ' "$tempDir/Packages" \
            && echo "deb [ trusted=yes ] file://$tempDir ./" > /etc/apt/sources.list.d/temp.list \
# work around the following APT issue by using "Acquire::GzipIndexes=false" (overriding "/etc/apt/apt.conf.d/docker-gzip-indexes")
#   Could not open file /var/lib/apt/lists/partial/_tmp_tmp.ODWljpQfkE_._Packages - open (13: Permission denied)
#   ...
#   E: Failed to fetch store:/var/lib/apt/lists/partial/_tmp_tmp.ODWljpQfkE_._Packages  Could not open file /var/lib/apt/lists/partial/_tmp_tmp.ODWljpQfkE_._Packages - open (13: Permission denied)
            && apt-get -o Acquire::GzipIndexes=false update \
            ;; \
    esac \
    \
    && apt-get install --no-install-recommends --no-install-suggests -y \
                        $nginxPackages \
                        gettext-base \
                        curl \
    && apt-get remove --purge --auto-remove -y && rm -rf /var/lib/apt/lists/* /etc/apt/sources.list.d/nginx.list \
    \
# if we have leftovers from building, let's purge them (including extra, unnecessary build deps)
    && if [ -n "$tempDir" ]; then \
        apt-get purge -y --auto-remove \
        && rm -rf "$tempDir" /etc/apt/sources.list.d/temp.list; \
    fi \
# forward request and error logs to docker log collector
    && ln -sf /dev/stdout /var/log/nginx/access.log \
    && ln -sf /dev/stderr /var/log/nginx/error.log \
# create a docker-entrypoint.d directory
    && mkdir /docker-entrypoint.d

COPY docker-entrypoint.sh /
COPY 10-listen-on-ipv6-by-default.sh /docker-entrypoint.d
COPY 20-envsubst-on-templates.sh /docker-entrypoint.d
COPY 30-tune-worker-processes.sh /docker-entrypoint.d
ENTRYPOINT ["/docker-entrypoint.sh"]

EXPOSE 80

STOPSIGNAL SIGQUIT

CMD ["nginx", "-g", "daemon off;"]

Also FYI jwilder isn't an active maintainer of this repo anymore.

[jastlw]

Hi @buchdag,

thanks for your response. :)
I asked the nginx people and it seems that the nginx docker images is already supporting smtp.
Here: nginxinc/docker-nginx#795 (comment)

Therefore, you do not need to maintain your own nginx image right?

Thanks

Jakob

[buchdag]

Thanks for the info, nginx in the upstream container is indeed already compiled with --with-mail and --with-mail_ssl_module, I'll look into nginx's mail proxy documentation.