Re: [ALUG] Odd networking issue; losing packets?
I have a Windows XP box and a Ubuntu 8.10 box plugged in to the same router. FWIW, it's a BT HomeHub 2 that I'm currently trialling.
Both work, although for some reason the Ubuntu box has an odd tracert:
$ sudo tracert 216.239.59.147 traceroute to 216.239.59.147 (216.239.59.147), 30 hops max, 40 byte packets 1 BThomehub.home (192.168.1.254) 55.623 ms 55.417 ms 55.174 ms 2 217.47.200.58 (217.47.200.58) 33.711 ms * * 3 * * * 4 * * * 5 * * * 6 * 217.41.170.65 (217.41.170.65) 41.333 ms * 7 * 217.41.170.122 (217.41.170.122) 31.084 ms 33.988 ms 8 * * * 9 * * * 10 * * * 11 * * * 12 * * 195.99.125.82 (195.99.125.82) 33.735 ms 13 * * * 14 * * * 15 * * * 16 * * * 17 gv-in-f147.google.com (216.239.59.147) 45.999 ms * *
Compare that with the Windows box; C:\>tracert www.google.com
Tracing route to www.l.google.com [216.239.59.147] over a maximum of 30 hops:
1 43 ms 100 ms 99 ms BThomehub.home [192.168.1.254] 2 476 ms 395 ms 435 ms 217.47.200.58 3 179 ms 184 ms 187 ms 217.47.250.161 4 191 ms 32 ms 62 ms 217.47.200.10 5 63 ms 63 ms 153 ms 217.41.170.21 6 82 ms 62 ms 97 ms 217.41.170.65 7 234 ms 215 ms 122 ms 217.41.170.122 8 206 ms 183 ms 183 ms 217.41.170.50 9 230 ms 244 ms 245 ms 217.47.200.241 10 470 ms 320 ms 307 ms core1-pos0-0-0-5.ilford.ukcore.bt.net[194.72.20.113] 11 370 ms 367 ms 369 ms core1-pos14-1.telehouse.ukcore.bt.net[195.99.125.225] 12 423 ms 490 ms 453 ms 195.99.125.82 13 422 ms 423 ms 409 ms 209.85.255.175 14 45 ms 67 ms 93 ms 209.85.250.216 15 101 ms 151 ms 123 ms 66.249.95.164 16 203 ms 184 ms 185 ms 216.239.49.114 17 249 ms 249 ms 242 ms gv-in-f147.google.com [216.239.59.147]
Trace complete.
It seems to me that the Linux box is losing lots of packets. Many get through, but many do not. Or am I just worrying about nothing, given that it seems to work OK. On the bright side, those packets that do get through do so a lot quicker than those on Windows, but that may be just because my Linux box is less archaic.
Any ideas?
Thanks,
Hi Greg, Linux traceroute and WIndows traceroute work in different ways. Linux uses UDP packets, and WIndows uses ICMP. From your Linux machine try traceroute -I www.google.co.uk and then try without the -I. THe -I forces the Linux traceroute to behave like the Windows one. Some routers block excessive UDP traffic, as they see it as an attack. My Draytek router blocks UDP pings, I always have to use -I on traces. Hope that helps Chris
2009/2/17 <lists@glover.uk.net>
I have a Windows XP box and a Ubuntu 8.10 box plugged in to the same router. FWIW, it's a BT HomeHub 2 that I'm currently trialling.
Both work, although for some reason the Ubuntu box has an odd tracert:
Linux traceroute and WIndows traceroute work in different ways. Linux uses UDP packets, and WIndows uses ICMP. From your Linux machine try traceroute -I www.google.co.uk and then try without the -I. THe -I forces the Linux traceroute to behave like the Windows one.
That made no difference but ...
Some routers block excessive UDP traffic, as they see it as an attack. My Draytek router blocks UDP pings, I always have to use -I on traces.
That did help. I checked the router logs (*), and it was showing both UDP and ICMP tracert's as intrusions. A quick check of the man page for tracert, and it seems that $ traceroute -N 1 www.google.co.uk does the trick, by only sending one packet at a time and hence not triggering the intrusion detection. Thanks for the pointer, I'll feed it back to the trial team to see if they can get a FAQ updated for the HH somewhere. Greg
On Tue, Feb 17, 2009 at 07:26:36PM +0000, Greg Thomas wrote:
2009/2/17 <lists@glover.uk.net>
> I have a Windows XP box and a Ubuntu 8.10 box plugged in to the same > router. > FWIW, it's a BT HomeHub 2 that I'm currently trialling. > > Both work, although for some reason the Ubuntu box has an odd tracert:
Linux traceroute and WIndows traceroute work in different ways. Linux uses UDP packets, and WIndows uses ICMP. From your Linux machine try traceroute -I www.google.co.uk and then try without the -I. THe -I forces the Linux traceroute to behave like the Windows one.
That made no difference but ...
Some routers block excessive UDP traffic, as they see it as an attack. My Draytek router blocks UDP pings, I always have to use -I on traces.
That did help. I checked the router logs (*), and it was showing both UDP and ICMP
... and of course it explains my recent traceroute result when I was trying to diagnose my "some web sites hang" problem, I have a Draytek router too so the traceroute produced nothing at all. If/when it happens again I can try a 'traceroute -I <wherever>'.
tracert's as intrusions. A quick check of the man page for tracert, and it seems that $ traceroute -N 1 www.google.co.uk does the trick, by only sending one packet at a time and hence not triggering the intrusion detection.
Thanks for the pointer, I'll feed it back to the trial team to see if they can get a FAQ updated for the HH somewhere.
Greg
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