[pups] very strange problems with 2.11BSD tcp/ip stack

[Edward Brocklesby]

hi,

I've been using the 2.11BSD tcp/ip stack fine for weeks, but now, just when 
we move it to a new host, its been very flaky.. I'm not sure if it's a 
problem with the configuration of the emulator host system, or the TCP stack 
itself.

the problem seems to be with packets arriving and being processed out of 
order.. I get this from a ping:
PING 62.242.39.162 (62.242.39.162): 56 data bytes
64 bytes from 62.242.39.162: icmp_seq=2 ttl=255 time=14.427 ms
64 bytes from 62.242.39.162: icmp_seq=3 ttl=255 time=24.571 ms
64 bytes from 62.242.39.162: icmp_seq=0 ttl=255 time=3194.977 ms
64 bytes from 62.242.39.162: icmp_seq=1 ttl=255 time=2207.308 ms
64 bytes from 62.242.39.162: icmp_seq=12 ttl=255 time=14.602 ms
64 bytes from 62.242.39.162: icmp_seq=13 ttl=255 time=24.598 ms
64 bytes from 62.242.39.162: icmp_seq=14 ttl=255 time=14.612 ms
64 bytes from 62.242.39.162: icmp_seq=15 ttl=255 time=24.571 ms
64 bytes from 62.242.39.162: icmp_seq=16 ttl=255 time=14.614 ms
64 bytes from 62.242.39.162: icmp_seq=4 ttl=255 time=12156.845 ms
64 bytes from 62.242.39.162: icmp_seq=5 ttl=255 time=11166.777 ms
64 bytes from 62.242.39.162: icmp_seq=6 ttl=255 time=10176.688 ms
64 bytes from 62.242.39.162: icmp_seq=7 ttl=255 time=9186.604 ms
64 bytes from 62.242.39.162: icmp_seq=8 ttl=255 time=8197.344 ms
64 bytes from 62.242.39.162: icmp_seq=9 ttl=255 time=7206.744 ms
64 bytes from 62.242.39.162: icmp_seq=10 ttl=255 time=6216.641 ms
64 bytes from 62.242.39.162: icmp_seq=11 ttl=255 time=5226.532 ms

but the box i'm pinging from is the host system where the emulator is 
located.. so there isn't any possible network problem. 

The configuration is, tap0 has the IP 62.242.39.161 on the host, and the 
pdp-11 has 62.242.39.162, with netmask 0xfffffff8.  Nothing else special has 
been done on either side.

on the host, we have this:

freeze% ifconfig xl0
xl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        inet 195.249.6.94 netmask 0xfffffff8 broadcast 195.249.6.95
        inet6 fe80::260:97ff:fe7d:74ac%xl0 prefixlen 64 scopeid 0x1
        ether 00:60:97:7d:74:ac
        media: 100baseTX <full-duplex> status: active
        supported media: autoselect 100baseTX <full-duplex> 100baseTX 
10baseT/UTP <full-duplex> 10baseT/UTP 100baseTX <hw-loopback>
freeze% ifconfig tap0
tap0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1532
        inet6 fe80::260:97ff:fe7d:74ac%tap0 prefixlen 64 scopeid 0xb
        inet 62.242.39.161 netmask 0xfffffffc broadcast 62.242.39.163
        ether 00:bd:e7:e0:cc:00
        Opened by PID 31257
freeze% netstat -rn
Routing tables
 
Internet:
Destination        Gateway            Flags     Refs     Use     Netif Expire
default            195.249.6.90       UGSc        2     8355      xl0
62.242.39.160/30   link#11            UC          0        0     tap0 =>
127.0.0.1          127.0.0.1          UH          2    15389      lo0
195.249.6.88/29    link#1             UC          0        0      xl0 =>


and on the pdp-11:

styx% ifconfig qe0
qe0: flags=63<UP,BROADCAST,NOTRAILERS,RUNNING>
        inet 62.242.39.162 netmask fffffffc broadcast 62.242.39.163
styx% netstat -rn
Routing tables
Destination      Gateway            Flags     Refs     Use  Interface
127.0.0.1        127.0.0.1          UH          0        0  lo0
62.242.39.162    127.0.0.1          UH          0        0  lo0
default          62.242.39.161      UG          1     3551  qe0
62.242.39.160    62.242.39.162      U           1      321  qe0

If someone could shed some light on this problem, it'd be much appreciated..

	-larne-