Re: [SLE] Fetchmail Daemon Problem

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 The mail server was rejecting this mails with the header filter, and now it is solved! sorry! Lorenzo. On Sunday 01 August 2004 19:23, you wrote:

The Saturday 2004-07-31 at 20:05 -0500, Patrick Shanahan wrote:

...

...

You can use the headers_checks in either case, with a trick. Or, better, I think, the "access" file (less cpu, acts earlier):

agree that 'access' is probably a better choice for the reason you present. Header_checks would be better for a string in 'subject' or other part of the header other than a 'From:' address.

Exactly. But previously I also used header-checks.

...

...

# rules to reject unwanted email Mailer-Daemon@orinoco.dattaorinoco.com REJECT Blocking backscatter mail from virus scanners

the chars after REJECT are comments ??

No, they are given back as a reject reason in the smtp dialog - in my case, to fetchmail, otherwise, to whatever is at the other side. See the logs:

Jun 18 12:02:09 nimrodel fetchmail[4865]: SMTP> MAIL FROM: SIZE=43906 Jun 18 12:02:09 nimrodel fetchmail[4865]: SMTP< 250 Ok Jun 18 12:02:09 nimrodel fetchmail[4865]: SMTP> RCPT TO: Jun 18 12:02:09 nimrodel postfix/smtpd[4938]: NOQUEUE: reject: RCPT from localhost[127.0.0.1]: 554 : Sender address rejected: Blocking backscatter mail from virus scanners; from= to= proto=ESMTP helo=<localhost> Jun 18 12:02:09 nimrodel fetchmail[4865]: SMTP< 554 : Sender address rejected: Blocking backscatter mail from virus scanners Jun 18 12:02:09 nimrodel fetchmail[4865]: SMTP error: 554 : Sender address rejected: Blocking backscatter mail from virus scanners Jun 18 12:02:09 nimrodel fetchmail[4865]: SMTP listener doesn't like recipient address `cer@localhost'

Then fetchmail tries to send back a reject message - it has to, of course, because it can not talk back to the original smtp sender, that would have to be done by the pop3 server. But I don't allow fetchmail to send that reject message, because an "access" rule affects both sender and destination addresses:

Jun 18 12:02:09 nimrodel fetchmail[4865]: SMTP> RCPT TO: Jun 18 12:02:09 nimrodel postfix/smtpd[4938]: NOQUEUE: reject: RCPT from localhost[127.0.0.1]: 554 : Sender address rejected: Blocking backscatter mail from virus scanners; from= to= proto=ESMTP helo=<localhost> Jun 18 12:02:09 nimrodel fetchmail[4865]: SMTP< 554 : Sender address rejected: Blocking backscatter mail from virus scanners Jun 18 12:02:09 nimrodel fetchmail[4865]: can't even send to postmaster!

¿See? Its funny seeing fetchmail in distress ;-)

By the way, I took the sentence "Blocking backscatter mail from virus scanners" from the postfix site. The problem is that some sites have virus scanners that reject viruses, sending back to the apparent originator (which is faked, of course) the received email, complete with the virus load intact. Very "nice" of them, they are compounding the problem: that's backscatter mail.

You see the whole conversation takes one second; unfortunately, fetchmail (or the pop3 server) takes some time before moving on to the next message (and time, with a modem, is money):

Jun 18 12:02:10 nimrodel fetchmail[4865]: SMTP> RSET Jun 18 12:02:10 nimrodel fetchmail[4865]: SMTP< 250 Ok Jun 18 12:02:21 nimrodel fetchmail[4865]: flushed Jun 18 12:02:21 nimrodel fetchmail[4865]: POP3> DELE 75 Jun 18 12:02:21 nimrodel fetchmail[4865]: POP3< +OK message marked for deletion Jun 18 12:02:21 nimrodel fetchmail[4865]: POP3> RETR 76

The delay is not due to the problem I reported with SuSE 9.1, because this particular log entry belongs to SuSE 8.2 - no, now that I think, it will be because fetchmail is trying to send back the whole original email! It is also a backscatter originator :-(

Cute problem, backscatter email...

...

...

# This rule redirects email sent by _my_ fetchmail. If I don't do this, # for every reject (above) fetchmail will send another email explaining # the reject. FETCHMAIL-DAEMON@nimrodel.valinor REDIRECT virusalert@localhost

You do this in 'access' ?? or in virtual ????

In access as well, yes. Redirect is a new addition, I wanted to use it. Virtual... well, perhaps :-?

Ah, no, I used it because an "access" rule works even for a match on the "From" part, thus triggering when fetchmail sends email. I forgot to document it O:-)

...

...

I also have script to process email sent to virusalert and create logs instead.

Procmail ??

Right. :-)

A quick hack: :0

* ^From.*FETCHMAIL-DAEMON@nimrodel.valinor {

:0 c

$HOME/Mail/root/in_fetchmail

:0 : | cat > $HOME/bin/pfb.input ; $HOME/bin/pfb

}

Then I parse that email using the script HOME/bin/pfb. I don't like that 'cat' there, but it works.

That reminds me, I have to revise it, something has changed when I upgraded and some info is missing from the log I generate.

-- Cheers, Carlos Robinson

- -- Lorenzo Maldonado M. Ovoplus del Centro S.A. de C.V. Tel/Fax: 55872707 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (GNU/Linux) iD8DBQFBDq3Gv7QrazZAdS0RAvNNAJwMRTzJuF67nEmeXXRtBwdkZE75NgCgsDkF u6OkJ/DgWXNQfQNn8LU2aiM= =/1fK -----END PGP SIGNATURE-----