https://github.com/mildis/opensmtpd-go-filter-prepend

OpenSMTPD filter which prepends a string on email's subject if not present
https://github.com/mildis/opensmtpd-go-filter-prepend

go opensmtpd opensmtpd-filter

Last synced: 24 days ago
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OpenSMTPD filter which prepends a string on email's subject if not present

• Host: GitHub
• URL: https://github.com/mildis/opensmtpd-go-filter-prepend
• Owner: mildis
• License: gpl-3.0
• Created: 2020-03-29T10:50:29.000Z (over 4 years ago)
• Default Branch: master
• Last Pushed: 2022-01-16T15:09:20.000Z (almost 3 years ago)
• Last Synced: 2024-10-13T14:10:48.261Z (2 months ago)
• Topics: go, opensmtpd, opensmtpd-filter
• Language: Go
• Homepage:
• Size: 28.3 KB
• Stars: 2
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
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# opensmtpd-go-filter-prepend

OpenSMTPD filter which prepends a string on email's subject if not present.  

Works with OpenSMTPD 6.6 and 6.7.

## Usage

* build the filter for your target platform  

`env GOOS=openbsd GOARCH=amd64 go build filter-prepend.go`

* make OpenSMTPD use the filter

```

filter prepend proc-exec "filter-prepend-go --prefix='[*EXT*]' --extraprefix='[EXT]'"

listen on em0 tls pki "*" filter { senderscore, rspamd, prepend }

```

* default prefix is `[*EXT*]` if not specified on the CLI  

* default extraprefix is `[EXT]` if not specified on the CLI  

Be warned that a too generic prefix could match legitimate wording and thus it won't be added to the Subject

* option `--encode` forces prefix encoding whether the subject is encoded or not.

## Known limitations

1. if Subject is too long and spans between multiple datalines, only the begining will be analyzed for prefix token

2. RFC2047 Subject won't be decoded if 1/ happens inside an encoded string