#procmail

用 procmail 判斷信件是否有過 DKIM Signature

這年頭自己維護 mail account 的情況比較少了，所以資料不太好找，測出來寫下來讓其他人也可以用…

這邊說的是透過 procmail 判斷信件是否符合 DKIM Signature，然後加上 header。

如果是 Ubuntu 環境，首先在要裝上 python-dkim (不是 python3-dkim)：

sudo apt install -y python-dkim

我們需要裡面的 dkimverify 程式透過 stdin 讀信件進去，然後透過 exit code 告知有沒有成功。

對應的 .procmailrc 是這樣：

# DKIM :0 * ^DKIM-Signature: { :0BHWf * ? /usr/bin/dkimverify | /usr/bin/formail -A "X-Procmail-DKIMVerify: pass" :0Ef |…

Fix: Is there a way to filter mails in remote IMAP account? #it #programming #dev

Is there a way to filter mails in remote IMAP account?

Situation: mail server with IMAP only access. Problem: I want to be able to filter mails (put some mails to various folders, mark them as read and so on).

Most new email clients have this ability, but I want a standalone filtering program, as I need to use various email clients to connect to this server.

Generally – something like procmail,…

There's lots rc settings in procmail, recipe format is:

:0 [flags] [ : [locallockfile] ] <zero or more conditions (one per line)> <exactly one action line>

Examples are listed:

1. Accept email which prefix starts from alphabets:

:0: $LOCK * !^From [a-zA-Z][a-zA-Z].*@.* junk

2. Mail size larger than 256k, put it in another mbox:

:0 * > 256000 larger

3. Accept all (usually put in the bottom of .procmailrc):

:0 ${DEFAULT}

4. Mailing list classifier:

:0 * ^Sender:.owner-freebsd-\/[^@][email protected] {         LISTNAME=${MATCH}         :0:         * LISTNAME??^\/[^@]+         ${HOME}/Mail/freebsd/freebsd-${MATCH} }

Because I do feel like I'm the last one. Like the last Samurai or something like that. Of course I'm talking about desktop users not on servers (where it's probably still relatively widespread).

The other day I was pondering that I hadn't touched my mail delivering set up for years since I started using the combination of fetchmail + procmail for pop fetching, mutt as MUA and postfix as smtp server. I'm talking of around 9-10 years at least. I only added offlineimap to the configuration 4 years ago for syncing gmail mailboxes via imap.

There have been some new software that menaced this set up, like getmail instead of fetchmail, mstmp for simple smtp relying and fdm as a total replacement. None of those really moved me into changing my set up. Getmail is mostly equivalent to fetchmail while mstmp simply sends the outbound mails to a smtp server of choice, much like what I have configured postfix to do as I am on a dial-up connection and the isp would ban me if I'd use a smtp server without a full qualified hostname. Yet today I installed fdm and started configuring it but stopped without finishing for two reasons: 1. I don't receive much pop3 mail anyway. I might simply use mutt to read the new mails once in a while and copy them the hard disk if I wanted to keep them. This way neither fetchmail + procmail nor fdm would be needed at all. 2. I didn't like to learn a new program, with different regular expression rules (for 's sake, Regular Expressions!), make it work as procmail has always done and then test it simply to have 1 software instead than 2 (and saving 1,9Mb of space).