Hi, I am using syslog-ng to do log collection and "routing" to different destinations based on the origin of the log. I used to (still do in some cases) filter like this: filter f_one_list { host("10.0.0.1") or host("10.0.2.1") or ... host("10.3.4.5"); } Since (too) many log sources break the RFC and put all kinds of strangeness in the "header", I started using netmask instead: filter f_another_list { netmask("10.0.0.1/32") or netmask("10.0.2.1/32") or ... netmask("10.3.4.5/32"); } My question is this - Is there a measurable performance difference from one to another? "intuitively" it would seem doing the netmask check should be faster than parsing the syslog header, but I thought I'd ask here. (currently I have some servers processing 4000+ messages per second with no real problem, but the CPUs are clearly busy. BTW - I am using 3.2.4 at the moment (looking at moving to the multi-threaded newer versions in the future) Thanks! Jim Hendrick