Mail testing tool

README.md

Mail server testing

A quick script and data file that allows a test of a non-secured mail server

Typically useful to check if a service is actually working, you'll need to activate non-login non-SSL on your server

For obvious reasons, do NOT leave your SMTP server in that state for too long on the open Internet!

Example use of command:

./testmail.sh mail-session.txt mail.company.tld

mail-session.txt

# vim: set filetype=conf :
# Comment lines are ignored
# Empty lines are part of the session
#
# Use comments for spacing
#
#
# Send EHLO to initiate session
EHLO sender.company.tld
# From address - any will do
MAIL FROM: test@company.tld
# Please set this to your own address...!
RCPT TO: me@company.tld
# Declare that we're going to send the actual mail data
#   the above was routing info, of sorts
DATA
# Anything you want
From: noreply@company.tld
# This can be anything too! The routing was set above!
To: you@company.tld
Subject: Test mail
# Empty line to signal start of message

# Start of message
Hello

This is a test message

# Single dot to end message
.
# Actually close the session
QUIT

testmail.sh

#!/usr/bin/env bash

set -euo pipefail

TELNET=(:)

die() {
    echo "$*" >&2
    exit 1
}

printhelp() {
cat <<EOHELP

"$0" MAILFILE SERVER [PORT]

Use MAILFILE as a SMTP session

Sending to SERVER

Through PORT (default 25)

EOHELP

if [[ -n "$*" ]]; then exit "$1"; fi
}

getbin() {
    local cmd
    for cmd in "$@"; do
        if which "$cmd" 2>&1 >/dev/null; then
            echo "$cmd"
            return
        fi
    done
}

set_telnet() {
    local command="$(getbin telnet busybox)"

    if [[ "$command" = telnet ]]; then
        TELNET=(: telnet)
    elif [[ "$command" = busybox ]]; then
        TELNET=(: busybox telnet)
    else
        die "No telnet client available"
    fi
}

main() {
    local mailfile="${1:-}"; shift || printhelp 1
    local server="${1:-}"; shift || printhelp 1
    local port="${1:-}"; shift || port=25

    set_telnet

    [[ "$port" =~ ^[0-9]+ ]] || die "Port '$port' is not a number"
    
    set -x
    grep -Pv '^\s*#' "$mailfile" | tee /dev/stderr | "${TELNET[@]:1}" "$server" "$port"
}

main "$@"

Had a problem with telnet this time, so here's an alternative (needs bbrun from https://gitlab.com/taikedz/bash-builder)

#!/usr/bin/env bbrun

set -euo pipefail

#%include std/out.sh
#%include std/syntax-extensions.sh

SEC=0.5

$%function readsession(sessionfile) {
    out:info "Print every $SEC seconds"

    while read line; do
        echo "$line"|tee -a /dev/stderr

        sleep $SEC
    done < <(grep -Pv '^#' "$mailfile")
}

$%function main(mailrelay sessionfile) {
    out:info "Server: $mailrelay"
    out:info "Session: $sessionfile"
    nc -C "$mailrelay" 25  < <(readsession "$sessionfile")| tee output.smtp

    local expected="Queued mail for delivery"

    (grep -q "$expected" output.smtp && out:info "Success.") || out:fail "Did not find the expected message: '$expected'"
}

main "$@"