Hi.

As far as I can see, my email setup is fine. MX record OK, I can send and receive email, etc. But I sourceforge.net seems to refuse connections from my linode, I can't tell why. This is what happens:

Jul 21 07:04:43 localhost postfix/smtpd[30721]: connect from lists.sourceforge.net[66.35.250.206]
Jul 21 07:05:29 localhost postfix/smtp[30716]: E418342390: to=<sbcl-help-request@lists.sourceforge.net>, relay=mail.sourceforge.net[66.35.250.206]:25, delay=347517, delays=347466/0.07/5.1/46, dsn=4.0.0, status=deferred (host mail.sourceforge.net[66.35.250.206] said: 451-Could not complete sender verify callout 451-Could not complete sender verify callout for 451-<MY-EMAIL@randomnode.info>. 451-The mail server(s) for the domain may be temporarily unreachable, or 451-they may be permanently unreachable from this server. In the latter case, 451-you need to change the address or create an MX record for its domain 451-if it is supposed to be generally accessible from the Internet. 451 Talk to your mail administrator for details. (in reply to RCPT TO command))
Jul 21 07:05:30 localhost postfix/smtpd[30721]: NOQUEUE: reject: RCPT from lists.sourceforge.net[66.35.250.206]: 503 5.5.0 <>: Sender address rejected: Improper use of SMTP command
 pipelining; from=<> to=<MY-EMAIL@randomnode.info> proto=SMTP helo=<mail.sourceforge.net>
Jul 21 07:05:30 localhost postfix/smtpd[30721]: disconnect from lists.sourceforge.net[66.35.250.206]

It seems to me that they're doing something wrong, but I'm not sure... My MX record is working fine, as always:

dig mx randomnode.info
;; ANSWER SECTION:
randomnode.info.        3600    IN      MX      0 mail.randomnode.info.

;; ADDITIONAL SECTION:
mail.randomnode.info.   2349    IN      A       64.62.231.90

And my MX IP is not listed in any SPAM databases that I know of (I checked from dnsstuff.com).

Any other ideas of what could be wrong?

Thanks a lot,
-- jp

It looks like Sourceforge is doing SMTP callbacks. It's a way to reduce spam. It means that the receiving server (in this case, Sourceforge), while it's deciding whether or not to accept your message, makes a connection back to your mail server to make sure you actually exist.

This is a pretty good strategy; I use it myself.

It may be that your mail server doesn't accept the null sender. It should, because the RFCs say it should, and because that's how you get bounces.

Here's a session where I simulated an SMTP callback with your server. I don't know a real address, so I can't say if it really works or not.

# telnet mail.randomnode.info smtp
Trying 64.62.231.90...
Connected to li7-90.members.linode.com.
Escape character is '^]'.
220 randomnode.info NO UCE ESMTP
helo charbonnet.com
250 randomnode.info
mail from: <>
250 2.1.0 Ok
rcpt to: <test@randomnode.info>
554 5.7.1 <test@randomnode.info>: Recipient address rejected: Access denied

[quote="Xan"]It looks like Sourceforge is doing SMTP callbacks. It's a way to reduce spam. It means that the receiving server (in this case, Sourceforge), while it's deciding whether or not to accept your message, makes a connection back to your mail server to make sure you actually exist.

This is a pretty good strategy; I use it myself.

It may be that your mail server doesn't accept the null sender. It should, because the RFCs say it should, and because that's how you get bounces.
[/quote]

These all happen to be exactly the case. There's also graylisting involved.

My mail server does accept the null sender (just tested).
This is really strange. I think my mail server is complaining about SF's mail server setup: SF is doing improper SMTP pipelining, which my postfix isn't allowing...

Jul 22 06:28:11 localhost postfix/smtpd[6201]: NOQUEUE: reject: RCPT from lists.sourceforge.net[66.35.250.206]: 503 5.5.0 <>: Sender address rejected: Improper use of SMTP command pipelining; from=<> to=<j.pellegrini@randomnode.info> proto=SMTP helo=<mail.sourceforge.net>

Guess I'll have to either give up posting to SF or accept SMTP pipelining...

I'd write to the Sourceforge postmaster and see if he has any suggestions.

Did that yesterday... But I'm not expecting any kind of answer from them. I've had almost only bad experiences trying to get any useful answer from postmasters.

Another tactic would be sniff the transaction (listen to eveything involving the SF server) and see what it's actually doing.

_________________
The irony is that Bill Gates claims to be making a stable operating system and Linus Torvalds claims to be trying to take over the world.
-- seen on the net

perhaps you just need a reverse dns entry , which you can setup through your linode manager...

_________________
use Carapace;

i had a problem a while back when my isp got bought by earthlink.

SF.net started giving me errors when the change happened because after the transfer happened, the postmaster@ e-mail address went away or something.

i told earthlink support about it, but they did nothing, but they had a mechanism in place to create e-mail addresses. so for a while i was postmaster. it resolved my SF problem and when the mailbox got full, earthlink took notice and took it away from me.. lol

so much junk in that thing i got tired of looking at it.