Processes are backing up

[Marc Perkel]

Got a strange problem with spamd that started on it's own. Processes are 
backing up - but spamd seems to be stuck not processing them or taking a 
very long time. Still have free memory and processor loads are not that 
high. It's as if spamd is waiting on something that isn't responding. 
Not sure what to look for.

Thanks in advance.