mtu/mru ISDN dialup.

[Leen Besselink <leen@wirehub.nl>]

Hi folks,

When I run tcpdump on my ippp0 connection to my ISP, I get a lot of
packets like this:

tcpdump: listening on ippp0
truncated-ip - 46 bytes missing!0.40.224.225 > 64.0.127.6: (frag 
26486:36@63512+) [tos 0x17] [ttl 0]
truncated-ip - 28 bytes missing!0.58.208.128 > 0.0.64.17: (frag
38871:36@63512+) [tos 0x17] [ttl 0]
194.165.94.5.53 > 195.86.113.3.1042: 41* 1/3/3 (159)
truncated-ip - 38 bytes missing!0.48.64.158 > 64.0.127.6: (frag
38871:36@63512+) [tos 0x17] [ttl 0]
64.28.67.48.80 > 195.86.113.3.63822: S 1395078506:1395078506(0) ack
13465379 win 16060 <mss 1460,nop,nop,sackOK> (DF)
truncated-ip - 46 bytes missing!0.40.67.158 > 64.0.127.6: (frag
38871:36@39312) [tos 0x17]
1.190.68.158 > 64.0.127.6: (frag 38871:36@39312) [tos 0x17]
truncated-ip - 436 bytes missing!64.28.67.48.80 > 195.86.113.3.63822: P
1:1461(1460) ack 407 win 16060 (DF)

This worries me a bit, so I put this in my /etc/ppp/ioptions:
mru 1000
mtu 1000

But it doesn't seem to help, what is normal for ISDN connections anyway ?

Or does someone think tcpdump just wrong or I got bad cabling (I wouldn't
be surprised).

tia,
	Lennie.