from http://www.howtoforge.com/forums/showthread.php?t=52750
saslauthd memory leak > fix 
 This is an old issue that still isn't resolved on debian & derivates ( others ? )
 maybe someone should include it in the howtos.

 issue:
 saslauthd's memory usage starts to climb handling invalid authentication requests, eventually eating all your server memory ( & swap ).
 this is in fact a very serious issue, as it facilitates (D)DOS attacks by someone sending lots of crap auth. requests until the OOM process killer kicks in.


 there's an easy workaround by changing /etc/default/saslauthd 
Code:
OPTIONS="-c -m /var/spool/postfix/var/run/saslauthd -r"
to
Code:
OPTIONS="-n 0 -c -m /var/spool/postfix/var/run/saslauthd -r"
adding "-n 0" effectively prevents the saslauthd daemon from using thread processes by using forks instead.
 ( on 1 of my servers it used up 8GB and 16GB swap.... which was freed up instantaneously upon changing the config and invoking /etc/init.d/saslauthd restart )

 if anybody has a better solution.. feel free to post