Date: Tue, 26 Dec 2006 18:45:39 -0800 From: "Stephan Wehner" <stephanwehner@gmail.com> To: freebsd-net@freebsd.org Subject: Diagnose co-location networking problem Message-ID: <e66d1efb0612261845t3da246aepfa5ba5fef4858d6a@mail.gmail.com>
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I just got a server and put it in a co-location. It runs RELEASE FreeBSD 6.1-RELEASE #0, pound, lighttpd and ruby on rails. Most of the times I find the server responds nicely. But periodically it doesn't respond properly when accessing its webpages: Type URL in browser, hit return, no page appears. Try again and again and after a few times it appears. Other sites are accessible during these problematic times. Also, in parallel I am connected to the server through ssh, and there are not problems with that. Even during those times when the web pages don't appear, I can type and see the result. Before installing it at the datacentre, the server was working without problems on the local network. So I am thinking the problem may be with the co-location operation. How can I make sure? How can I diagnose this? The only idea I had was to run tcpdump on my Linux client (tcpdump host stbgo.org), and indeed I can see entries lines this: 18:32:24.970139 sucrose.sugarmotor.net.34503 > vps-18-138.virtualprivateservers.ca.http: S 2468438613:2468438613(0) win 5840 <mss 1460,sackOK,timestamp 96924995 0,nop,wscale 0> (DF) 18:32:25.670135 sucrose.sugarmotor.net.34508 > vps-18-138.virtualprivateservers.ca.http: S 2493895298:2493895298(0) win 5840 <mss 1460,sackOK,timestamp 96925065 0,nop,wscale 0> (DF) 18:32:49.670152 sucrose.sugarmotor.net.34508 > vps-18-138.virtualprivateservers.ca.http: S 2493895298:2493895298(0) win 5840 <mss 1460,sackOK,timestamp 96927465 0,nop,wscale 0> (DF) [note next is almost half a minute later] 18:33:12.970162 sucrose.sugarmotor.net.34503 > vps-18-138.virtualprivateservers.ca.http: S 2468438613:2468438613(0) win 5840 <mss 1460,sackOK,timestamp 96929795 0,nop,wscale 0> (DF) 18:33:12.985071 vps-18-138.virtualprivateservers.ca.http > sucrose.sugarmotor.net.34503: S 2788301288:2788301288(0) ack 2468438614 win 65535 <mss 1460,nop,wscale 1,nop,nop,timestamp 708478538 96929795,sackOK,eol> (DF) But I am not sure what these lines are telling me; other than "sucrose" tried a few times, and then got a response (last line). Any hints? Thanks Stephan -- Stephan Wehner > http://stephan.sugarmotor.org > http://stephansmap.org > http://www.trafficlife.com > http://www.buckmaster.ca
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