Diagnose co-location networking problem

[Stephan Wehner]

Ok, thanks, I now ran tcpdump with -n.

Here I am testing with a little script that continuously accesses one
of the pages.
Right at the beginning it doesn't get very far: first response after 90 seconds.

What kind of DNS problem did you have in mind?

Stephan

$ sudo /usr/sbin/tcpdump -n host stbgo.org
Password:
tcpdump: listening on eth0
21:40:22.162536 192.168.2.54.35932 > 65.110.18.138.80: S
1526509984:1526509984(0) win 5840 <mss 1460,sackOK,timestamp 980
52714 0,nop,wscale 0> (DF)
21:40:25.160150 192.168.2.54.35932 > 65.110.18.138.80: S
1526509984:1526509984(0) win 5840 <mss 1460,sackOK,timestamp 980
53014 0,nop,wscale 0> (DF)
21:40:31.160150 192.168.2.54.35932 > 65.110.18.138.80: S
1526509984:1526509984(0) win 5840 <mss 1460,sackOK,timestamp 980
53614 0,nop,wscale 0> (DF)
21:40:43.160143 192.168.2.54.35932 > 65.110.18.138.80: S
1526509984:1526509984(0) win 5840 <mss 1460,sackOK,timestamp 980
54814 0,nop,wscale 0> (DF)
21:41:07.160149 192.168.2.54.35932 > 65.110.18.138.80: S
1526509984:1526509984(0) win 5840 <mss 1460,sackOK,timestamp 980
57214 0,nop,wscale 0> (DF)
21:41:55.160152 192.168.2.54.35932 > 65.110.18.138.80: S
1526509984:1526509984(0) win 5840 <mss 1460,sackOK,timestamp 980
62014 0,nop,wscale 0> (DF)
21:41:55.174033 65.110.18.138.80 > 192.168.2.54.35932: S
432853648:432853648(0) ack 1526509985 win 65535 <mss 1460,nop,ws
cale 1,nop,nop,timestamp 719800431 98062014,sackOK,eol> (DF)
21:41:55.174139 192.168.2.54.35932 > 65.110.18.138.80: . ack 1 win
5840 <nop,nop,timestamp 98062015 719800431> (DF)
21:41:55.175738 192.168.2.54.35932 > 65.110.18.138.80: P 1:15(14) ack
1 win 5840 <nop,nop,timestamp 98062015 719800431> (
DF)
21:41:55.290528 65.110.18.138.80 > 192.168.2.54.35932: . ack 15 win
33304 <nop,nop,timestamp 719800549 98062015> (DF)
21:41:55.290665 192.168.2.54.35932 > 65.110.18.138.80: P 15:73(58) ack
1 win 5840 <nop,nop,timestamp 98062027 719800549>
(DF)




On 12/26/06, alex at pilosoft.com <alex at pilosoft.com> wrote:
> On Tue, 26 Dec 2006, Stephan Wehner wrote:
>
> > 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.
> DNS.
>
> try tcpdump -n
>
> -alex
>
>


-- 
Stephan Wehner
> http://stephan.sugarmotor.org
> http://stephansmap.org
> http://www.trafficlife.com
> http://www.buckmaster.ca