Ok, thanks for ideas - many new things to test. So far no luck. Too bad i don't have first-hand access to any of the client machines who *do* have this problem. Next, I will go and switch the ethernet cable to a different slot on the router - kind of desperate, I know. Some more details: - this web server is a xen virtual guest system, with CentOS 5.4 - the problem surfaced yesterday morning (6th of May), after I had migrated all these web sites from an old Fedora box to this new CentOS system Does the problem affect other xen systems on the same box? I haven't tested this yet (I cannot reproduce the error). You could test yourself if you can see http://62.236.221.71 (the problem system) http://62.236.221.78 (another guest on the same xen host) If someone *cannot* see the 1st one, then it would be interesting to know if (s)he can see the 2nd one or not. - Jussi On 6.5.2010 22.00, Benjamin Franz wrote: > On 05/06/2010 11:42 AM, Ryan Manikowski wrote: >> >> Notice the op posted they get timeouts even when going directly to a >> numerical address (if the apache server is configured to respond to >> *:80 it should at least display something) >> >> Try using telnet from a client machine that can not connect. >> >> e.g. telnet host.name.here 80 >> >> or >> >> telnet xx.xxx.xxx.xxx 80 >> >> Try a few times and see if you're getting a timeout or if it connects >> every time. Run tcpdump on the apache server while sending the >> connection requests and see if the connection attempts show up at all. >> If they do not, then it's a network problem. >> > Try running 'ab' (the apache bench tool - see 'man ab' for how to use > it) against your server and see if you can provoke the timeouts. If you > can, then you are probably not configured to handle many quick > connections and should check (1) httpd.conf to make sure you don't have > an excessively low setting for 'MaxClients' or (2) a too low setting for > max open filehandles. Look in /etc/security/limits.conf - you should > have a line reading something similar to: > > > * - nofile 64000 > > > somewhere in it to raise the max number of open files. Busy web servers > need lots of filehandles. > > -- > Benjamin Franz > > -- > Benjamin Franz > > > > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos -- Jussi Hirvi * Green Spot Topeliuksenkatu 15 C * 00250 Helsinki * Finland Tel. +358 9 493 981 * Mobile +358 40 771 2098 (only sms) jussi.hirvi at greenspot.fi * http://www.greenspot.fi