Saturday, May 10, 2008

clamsmtp rbl support patch

clamsmtp is lightweight anti virus smtp proxy. You can put it in front or back of your smtp server. But if you run it in front of your smtp server and relay traffic back to your original smtp server, you cannot use any rbl server.

So, I decided to write a patch which adds this new rbl option to clamsmtpd server. You can download patch from here clamsmtp rbl patch

Tuesday, May 6, 2008

qmail linefeed problems hotmail , dcc and others

While I was testing DCC Checksum , I discovered that some email messages are truncated and dcc reports that body part is missing with an error message "missing message body". I figured out that not only the body part is missing also the headers also truncated.

A quick investigation with tcpdump showed that spamc is sending truncated messages to spamd server which is passed to dcc server. A second tcpdump run on smtp server showed that some messages is rejected by qmail server with "451 See" message. This was hitting a small amount of mails but the ones especially coming from

I have quickly fixed the problem with djb's fixcrio application which comes with DJB's ucspi-tcp package. No more "missing message body" error messages anymore with dcc :)

Running fixcrio is easy. Just put the command before qmail-smtpd where you run it.