This Go program is a SMTP-proxy that DKIM-signs e-mails before submission to an upstream SMTP-server.
Special thanks to @emersion for creating and providing the following Go libraries that are the main building blocks of this program:
- https://github.com/emersion/go-smtp
- https://github.com/emersion/go-smtp-proxy
- https://github.com/emersion/go-dkim
Additional dependencies are the following awesome Go libraries:
You basically have two options to install this Go program package:
- If you have Go installed and configured on your PATH, just do the following go get inside your GOPATH to get the latest version:
go get -u github.com/mback2k/smtp-dkim-signer
- If you do not have Go installed and just want to use a released binary, then you can just go ahead and download a pre-compiled Linux amd64 binary from the Github releases.
Finally put the smtp-dkim-signer binary onto your PATH and make sure it is executable.
The following YAML file is an example configuration with one virtual host:
Address: "localhost:25"
Domain: "localhost"
LetsEncrypt:
Agreed: true
Contact: [email protected]
Challenge: http
ChallengePort: 80
VirtualHosts:
- Domain: your-domain.tld
Upstream: "your-upstream-smtp:465"
Selector: "your-dkim-selector"
PrivKeyPath: "your-private-key-file" OR |
your-private-key-data
HeaderCan: "relaxed"
BodyCan: "simple"
HeaderKeys:
- "From"
- "Reply-To"
- "Subject"
- "Date"
- "To"
- "Cc"
- "In-Reply-To"
- "References"
- "Message-ID"
- "Resent-Date"
- "Resent-From"
- "Resent-To"
- "Resent-Cc"
# optional:
Rollbar:
AccessToken: "your-rollbar-access-token"
Environment: production
Save this file in one of the following locations and run ./smtp-dkim-signer:
- /etc/smtp-dkim-signer/smtp-dkim-signer.yaml
- $HOME/.smtp-dkim-signer.yaml
- $PWD/smtp-dkim-signer.yaml
Copyright (C) 2018 - 2020, Marc Hoersken [email protected]
This software is licensed as described in the file LICENSE, which you should have received as part of this software distribution.
All trademarks are the property of their respective owners.