I'm running an http-proxy (cern) and observed that some hosts simply can't
be accessed. I'm running 1.3.88 at home, being behind a CSLIP line, and
1.3.74 at university. below are two outputs from tcpdump, the first one
being my machine at home and the 2nd one the university machine.
suppose I do: "telnet localhost 80" and "GET http://www.derstandard.co.at",
www.derStandard.co.at = UNIX System V Release 4.0, then I see:
root@ferkel # tcpdump -i sl0
tcpdump: listening on sl0
02:01:45.366007 slip0.1070 > clannad.Austria.EU.net.www: S 316134894:316134894(0) win 512 <mss 256>
02:01:45.376007 slip0.domain > ist-gw.domain: 8+ (28)
02:01:45.606007 ist-gw.domain > slip0.domain: 8 2/4/4 (210)
02:01:45.646007 clannad.Austria.EU.net.www > slip0.1070: S 2051429957:2051429957(0) ack 316134895 win 8704 <mss 256> (DF)
02:01:45.646007 slip0.1070 > clannad.Austria.EU.net.www: . ack 1 win 13312
02:01:45.646007 slip0.1070 > clannad.Austria.EU.net.www: P 1:82(81) ack 1 win 13312
02:01:45.836007 slip0.1070 > clannad.Austria.EU.net.www: P 1:82(81) ack 1 win 13312
02:01:45.936007 clannad.Austria.EU.net.www > slip0.1070: . ack 82 win 8704 (DF)
02:01:46.046007 clannad.Austria.EU.net.www > slip0.1070: . ack 82 win 8704 (DF)
three packets ? and the first two at the same time ? is this correct ?
and now for the university machine:
linux-1:~# tcpdump host www.derstandard.co.at
tcpdump: listening on eth0
01:16:21.080893 linux-1.idv.uni-linz.ac.at.1141 > clannad.Austria.EU.net.www: S
1191844801:1191844801(0) win 512 <mss 536>
01:16:21.100893 clannad.Austria.EU.net.www > linux-1.idv.uni-linz.ac.at.1141: S
2129301367:2129301367(0) ack 1191844802 win 8576 <mss 536> (DF)
01:16:21.100893 linux-1.idv.uni-linz.ac.at.1141 > clannad.Austria.EU.net.www: .
ack 1 win 12864
01:16:21.100893 linux-1.idv.uni-linz.ac.at.1141 > clannad.Austria.EU.net.www: P
1:82(81) ack 1 win 12864
01:16:21.160893 clannad.Austria.EU.net.www > linux-1.idv.uni-linz.ac.at.1141: .
ack 82 win 8576 (DF)
only two packets, but sent at the same time too ?
hope this is of any help.
/herp