mutilated IP over nullmodem

Herbert Rosmanith (herp@wildsau.idv.uni-linz.ac.at)
Sat, 11 May 1996 22:12:01 +0200 (MET DST)


hello,

on a 38kbit nullmodem line (both systems use a 16550a), i see truncated
IP packets, regardless if using SLIP or CSLIP (havent tried PPP but I
doubt it will make anydifference) ... I even saw an ICMP Source Quench :)

any idea why this is happening ?

herp@wildsau.idv.uni-linz.ac.at

CSLIP
02:04:03.530204 truncated-ip - 1 bytes missing!192.168.1.250.1023 > 192.168.1.1.513: P 4175356476:4175356488(12) ack 761642696 win 13312 [tos 0x10]
02:04:11.590204 192.168.1.250.1041 > 192.168.1.1.23: S 213869027:213869027(0) win 512 <mss 256>
02:04:11.590204 192.168.1.1.23 > 192.168.1.250.1041: S 1095112669:1095112669(0) ack 213869028 win 13312 <mss 256>
02:04:11.630204 192.168.1.250.1041 > 192.168.1.1.23: . ack 1 win 13312
02:04:11.640204 192.168.1.250.1041 > 192.168.1.1.23: P 1:20(19) ack 1 win 13312
02:04:11.830204 truncated-ip - 7 bytes missing!192.168.1.250.1041 > 192.168.1.1.23: P 1:25(24) ack 1 win 13312
02:04:12.010204 192.168.1.1.23 > 192.168.1.250.1041: P 1:4(3) ack 1 win 13312
02:04:12.070204 192.168.1.250.1041 > 192.168.1.1.23: . ack 4 win 13312
02:04:12.460204 truncated-ip - 6 bytes missing!192.168.1.250.1041 > 192.168.1.1.23: P 1:25(24) ack 4 win 13312
02:04:13.260204 truncated-ip - 6 bytes missing!192.168.1.250.1041 > 192.168.1.1.23: P 1:25(24) ack 4 win 13312
02:04:14.860204 truncated-ip - 4 bytes missing!192.168.1.250.1041 > 192.168.1.1.23: P 1:25(24) ack 4 win 13312
02:04:18.060204 truncated-ip - 5 bytes missing!192.168.1.250.1041 > 192.168.1.1.23: P 1:25(24) ack 4 win 13312
02:04:23.630204 truncated-ip - 1 bytes missing!192.168.1.250.23 > 192.168.1.1.1149: P 3733217431:3733217434(3) ack 319492022 win 13312
02:04:24.460204 truncated-ip - 5 bytes missing!192.168.1.250.1041 > 192.168.1.1.23: P 1:25(24) ack 4 win 13312

SLIP (no VJ)
02:05:12.410204 192.168.1.250.1042 > 192.168.1.1.23: S 274689560:274689560(0) win 512 <mss 256>
02:05:12.410204 192.168.1.1.23 > 192.168.1.250.1042: S 1155932659:1155932659(0) ack 274689561 win 13312 <mss 256>
02:05:12.450204 192.168.1.250 > 192.168.1.1: icmp: source quench
02:05:12.450204 truncated-ip - 39913 bytes missing!32.251.33.255 > 251.34.251.36: (frag 64771:39935@55488+) [tos 0xb4]
02:05:12.650204 truncated-ip - 6 bytes missing!192.168.1.250 > 192.168.1.1: icmp: source quench
02:05:13.050204 truncated-ip - 5 bytes missing!192.168.1.250 > 192.168.1.1: icmp: source quench
02:05:15.400204 192.168.1.1.23 > 192.168.1.250.1042: S 1155932659:1155932659(0) ack 274689561 win 13312 <mss 256>
02:05:18.200204 truncated-ip - 5 bytes missing!192.168.1.250 > 192.168.1.1: icmp: source quench
02:05:18.210204 truncated-ip 4
02:05:18.210204 truncated-ip 3
02:05:18.650204 truncated-ip - 7 bytes missing!192.168.1.250 > 192.168.1.1: icmp: source quench
02:05:21.400204 192.168.1.1.23 > 192.168.1.250.1042: S 1155932659:1155932659(0) ack 274689561 win 13312 <mss 256>