_______________________________________________Hello Murrey,
Yep, I've done exactly this back in a previous life, where I was working as the networking odd-bod at a men's fashion retailer (please note that it doesn't mean I have fashion sense). We had a proprietary mail "firewall" at some point, which one day simply stopped working (I later found out that it was because we stopped paying for the service and the IT department, meaning me, was not informed). We had to put something in place pretty sharpish, and in the end we settled on a combination of Postfix and MailScanner. My chewing-gum and wet string solution served the company until well after I left.
You will have a wide choice of things to use that would probably be better than the above combination, but Postfix (combined with Dovecot) as the hub of your solution will do you proud. I currently use a combination of Postfix/Dovecot with amavisd-new to do content scanning, and PostGrey with spamd (SpamAssassin) to weed out the weirdness and rich widows from all over the world. It's not perfect, and it's definitely due for a redesign. Even so, it works well enough so that I rarely get something that defeats the system. I cannot remember getting virus messages for well over 10 years, and only a very few spammy bits make it through. To illustrate how high the rejected vs. received number is on my creaky setup, here is a snippet from my Postfix log summary as created by the pflogsumm tool:
---start--- Postfix log summaries for Feb 13 Grand Totals ------------ messages 135 received 145 delivered 1 forwarded 20 deferred (364 deferrals) 6 bounced 102 rejected (41%) 200 reject warnings 0 held 0 discarded (0%) 6726k bytes received 7469k bytes delivered 38 senders 30 sending hosts/domains 13 recipients 3 recipient hosts/domains Per-Hour Traffic Summary ------------------------ time received delivered deferred bounced rejected -------------------------------------------------------------------- 0000-0100 6 6 28 0 17 0100-0200 0 0 14 0 0 0200-0300 0 0 14 0 0 0300-0400 4 2 2 2 7 0400-0500 4 4 20 0 6 0500-0600 0 0 16 0 2 0600-0700 5 5 16 0 8 0700-0800 2 2 14 0 6 0800-0900 0 0 14 0 2 0900-1000 12 10 16 2 19 1000-1100 5 5 6 0 11 1100-1200 4 4 16 0 13 1200-1300 2 2 32 0 5 1300-1400 6 8 16 0 17 1400-1500 14 16 0 0 28 1500-1600 12 14 16 0 22 1600-1700 8 8 16 0 17 1700-1800 18 22 16 0 42 1800-1900 4 4 16 0 6 1900-2000 16 18 16 0 28 2000-2100 0 0 16 0 2 2100-2200 4 2 8 2 13 2200-2300 4 8 18 0 14 2300-2400 5 5 18 0 17 ---end---I hope this whets your appetite for some mail server nerdery.
Cheerio!Jan Henkins
On 17/02/2023 13:27, Murray Crane via BitFolk Users wrote:
Hello all,
Would any of you know if the following scenario is "doable"?
We run an old Exchange 2010 infrastructure at my work, and there is no way they are going to spring for newer: getting them to go from 2003 to 2010 was an ordeal...
Could I set up an Ubuntu Postfix "relay" server between Exchange and the Internet, that also permits one particular mailbox to be accessible from a Dovecot install on the same server (as well as relaying the mail for that mailbox to Exchange)?
Yes/no and pointers most welcomed.
Kind regards
Murray Crane
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