PGM Doesn't show SMTP Banner

[ccelis5215]

Hi all,

Sorry if this has been answered before.

Got a Carbonio CE and a PMG 7.3.3. Outgoing messages arrives to GMail, Outlook OK, TLS and DKIM signed by PGM and that's OK.

But, incoming mail doesn't work.

Testing with telnet from LAN works OK, but from internet not doesn't show SMTP banner... work after pressing enter key sometimes and then show Protocol error..

Any thoughts?

ccelis

 

[Stoiko Ivanov]

Not sure where the problem is exactly - but 2 guesses:
* on the external port PMG uses postscreen:
https://www.postfix.org/POSTSCREEN_README.html
and postscreen checks for protocol compliance and adds sleeps here and there - so maybe it works, but your tests with telnet don't follow the SMTP protocol well enough for postscreen

* your ISP is blocking incoming traffic on port 25 (not uncommon these days)
* the DNS setup of the domain is not correct and thus mail does not arrive

What does the journal/syslog say when you run your tests from the internet?

 

[ccelis5215]

Thank for answer.

Note that this is a vanilla Proxmox Mail Gateway and the outgoing messages arrives at GMail and Outlook.com OK but there's no incoming mail.

telnet mail1.domain.com 25

There's no 220 banner until press Enter

220-mail1.domain.com ESTMP Postfix
502 5.5.2 Error: command not recognized
EHLO mail1250-mail1.domain.com
250-SIZE 10485760
250-VRFY
250-ETRN
250-STARTTLS
250-ENHANCEDSTATUSCODES
250-8BITMIME
250-DSN
250-SMTPUTF8
250 CHUNKING
MAIL FROM: sender@domain.com250 2.1.0 Ok
RCPT TO: receipt@domain.com550 5.5.1 Protocol error

Jun 19 10:09:50 mail1 postfix/postscreen[2875]: CONNECT from [REMOTE-IP]:42383 to [192.168.1.64]:25
Jun 19 10:09:50 mail1 postfix/postscreen[2875]: PREGREET 2 after 0 from [REMOTE-IP]:42383:\r\n
Jun 19 10:09:50 mail1 postfix/postscreen[2875]: COMMAND PIPELINING from [REMOTE-IP]:42383 after : \r\n
Jun 19 10:10:17 mail1 postfix/postscreen[2875]: NOQUEUE: reject: RCPT from [REMOTE-IP]:42383: 550 5.5.1 Protocol error; from=<sender@domain.com>, to=<receipt@domain.com>, proto=ESMTP, helo=<mail1>
Jun 19 10:10:17 mail1 postfix/postscreen[2875]: DATA without valid RCPT from [REMOTE-IP]:42383
Jun 19 10:10:17 mail1 postfix/postscreen[2875]: DISCONNECT [REMOTE-IP]:42383

I'll apreciate your help...

ccelis

 

[Stoiko Ivanov]

Jun 19 10:10:17 mail1 postfix/postscreen[2875]: NOQUEUE: reject: RCPT from [REMOTE-IP]:42383: 550 5.5.1 Protocol error;

as guessed - your telnet commands are coming in too fast - thus postscreen detects the connection as coming from a bot ... wait until the actual greeting comes along

alternatively try using a test-tool which speaks the SMTP protocol parts for you - e.g. swaks