arachn1d wrote:
David, thanks. What you say makes sense and I'm trying to test against this but I can't seem to recreate the situation.
Well, it sounds like you have an almost nightly occurrence via external sources, so even if you can't generate the necessary load manually, tweak and then just wait a day :-)
Though as hybinet points out, the crucial point is how many simultaneous requests you initiate, not really the total number, since that's what causes all the Apache clients to be instantiated, and likely overloading your memory. You ought to be able to generate quite a few simultaneous connection attempts even over a slow client link.
It depends on your application stack, but MaxClients of 40 feels too high for a 768. Personally I'd have no worries about dropping it to 20 and then watching behavior. Odds are your normal usage won't be affected at all.
There are a number of Apache tuning threads here in the forums you might reference for other ways to benchmark your system. One at
viewtopic.php?t=6272 for example that covers some of the steps to take to monitor and test changes.
BTW, I had similar log patterns on an Apache server of minte in the past, and I've been wracking my brain trying to remember what I identified it as, as it didn't turn out to be malicious. Finally remembered...
In my case it ended up being incoming BitTorrent traffic, where a client behind the same firewall as the server had ended up choosing the same (non-standard) port as was being forwarded to Apache. So when the client stopped, for a period of time thereafter, I got incoming probes from BitTorrent clients looking for my peer, but now landing on Apache.
In general, your logs just say that some client using a binary protocol is connecting to the port Apache is listening on. So your case could be completely different, or could in fact be malicious, but perhaps this will help you think of other possibilities, especially if there's any chance that Apache is listening on a port that may be getting other uses, or proxy's or whatever.
-- David