On 5/22/21 11:29 AM, blackout69 wrote:

Hello everybody,

for a couple of days I have been seeing several lines calling these on /var/log/mail.log

May 22 18:22:57 glugct postfix/qmgr[21205]: 0ACE641C1B: from=<lug-bounces@catania.linux.it>, size=3698, nrcpt=9 (queue active) May 22 18:23:06 glugct postfix/qmgr[27175]: 0ACE641C1B: from=<lug-bounces@catania.linux.it>, size=3698, nrcpt=9 (queue active) May 22 18:23:36 glugct postfix/smtp[27177]: 0ACE641C1B: to=<myaddress@simail.it>, relay=none, delay=55152, delays=55122/0.07/30/0, dsn=4.4.1, status=deferred (connect to mail.simail.it[217.27.113.30]:25: Connection timed out) ... But always on a single email address.What could it depend on?Probable that the mail.simail.it server is blacklisted?

It's probably not blacklisting. It's not getting that far. Your glugct is attempting to connect to port 25 at mail.simail.it and the connect is not being answered. Normal blacklisting will not occur until after the remote MTA answers the connect and determines the IP of the caller. And in any case, if it is some kind of blacklisting it is your glugct server that is blacklisted by mail.simail.it.

I just did the following

$ telnet mail.simail.it 25
Trying 217.27.113.30...
Connected to mail.simail.it.
Escape character is '^]'.
220 mail.simail.it ESMTP ready.
quit
221 mail.simail.it closing connection
Connection closed by foreign host.

so it did answer my connect. In any case, this is not a Mailman issue. It is between Postfix on your server and the remote server at mail.simail.it.

-- Mark Sapiro <mark@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan

On 5/22/21 3:34 PM, blackout69 wrote:

I had already checked with the telnet command on port 25 and everything is fine.

Can you successfully telnet to port 25 on mail.simail.it from the Mailman server?

In this case, what strategy do you recommend?

If you can connect (via telnet) to port 25 on mail.simail.it from the Mailman server, then I'd suggest stopping and restarting Postfix.

-- Mark Sapiro <mark@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan

blackout69 writes:

Il 23/05/21 01:21, Mark Sapiro ha scritto:

...

Can you successfully telnet to port 25 on mail.simail.it from the Mailman server? No If you can connect (via telnet) to port 25 on mail.simail.it from the Mailman server, then I'd suggest stopping and restarting Postfix.

if i try from the mail server i get

telnet mail.simail.it 25 Trying 217.27.113.30... telnet: Unable to connect to remote host: Connection timed out

mail.simail.it is ignoring your mail server. This is not a Mailman problem.

1. Check to see if that server has a stated policy for "abusive" mail and some way of getting back in their good graces.
2. Check if your mail server is in the RBLs. Some of them are very aggressive about adding IPs and domains.
3. Try writing the postmaster at mail.simail.it.
4. Ask your subscriber(s) at mail.simail.it to write their postmaster.

Steve

peter@chubb.wattle.id.au writes:

Also check your firewall rules.

This is a good idea, although it seems unlikely in this case.

Outgoing port 25 is usually blocked by ISPs unless you explicitly ask for it not to be.

I don't think this is likely because the OP did say it seems to be only this one host, and ISPs generally block generically.

Steve

Il 23/05/21 03:06, peter@chubb.wattle.id.au ha scritto:

Also check your firewall rules. Outgoing port 25 is usually blocked by ISPs unless you explicitly ask for it not to be. Thanks Peter for your reply,

i checked my firewall rules and everything is ok. The problem occurs only for @ simail.it subscribers, all the others receive messages from the lists correctly.

--

blackout69

blackout69 writes:

After writing to postmaster@simail.it, today I was contacted by the technical assistance of mail.simail.it From today we are back in the whitelist :)

Great! I'm glad we could be of help. Thank you for the update. It's always nice to hear about the successes, and I guess we can add simail to the "good guys or at least responsive" list. :-)

The problem was caused by them. For some reason our server mail.catania.linux.it was in their blacklist.

That happens, even if you do everything right. I think you are doing everything right, so don't worry. And if you happen to have a similar problem, or a colleague or friend does, now you know how to deal with (even though it's still annoying.

Regards, Steve