>Number:         6899
>Category:       kern
>Synopsis:       Sending packets via IPIP interface doesn't work
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people (Kernel Bug People)
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Jan 28 03:05:00 1999
>Last-Modified:
>Originator:     Matthias Scheler
>Organization:
Matthias Scheler                                http://home.owl.de/~tron/
>Release:        990125
>Environment:
System: NetBSD lyssa.owl.de 1.3I NetBSD 1.3I (LYSSA) #1: Mon Jan 25 11:20:08 MET 1999 tron@lyssa.owl.de:/src/sys/compile/LYSSA i386


>Description:
Sinc the IPIP tunneling protocol has been moved to a seperate network
interface sending packets doesn't work any more:

tron@lyssa:~tron#ifconfig ipip0 192.168.1.1 194.123.65.34
tron@lyssa:~tron#ping -c 1 xpb.core.owl.de
PING xpb.core.owl.de (194.123.65.34): 56 data bytes
ping: sendto: Message too long
^C
----xpb.core.owl.de PING Statistics----
1 packets transmitted, 0 packets received, 100.0% packet loss

At this point it should have found a route and setup a valid MTU but
it didn't. So I set the MMU manually:

tron@lyssa:~tron#ifconfig ipip0 mtu 1500
tron@lyssa:~tron#ping -c 1 xpb.core.owl.de
PING xpb.core.owl.de (194.123.65.34): 56 data bytes

----xpb.core.owl.de PING Statistics----
1 packets transmitted, 0 packets received, 100.0% packet loss

If I use "tcpdump" on the router I can see them arriving on the
ethernet interface:

tron@colwyn:~tron#tcpdump -i de0 -s 1500 -xx proto 4
tcpdump: listening on de0
12:00:27.115060 192.168.1.1 > xpb.core.owl.de: icmp: echo request (ipip)
                         4500 0068 50c1 0000 ff04 a927 c0a8 0101
                         0000 0000 4500 0054 50c0 0000 ff01 a5a1
                         c0a8 0101 c27b 4122 0800 fbd3 05e0 0000
                         4b43 b036 0ecf 0100 0809 0a0b 0c0d 0e0f
                         1011 1213 1415 1617 1819 1a1b 1c1d 1e1f
                         2021 2223 2425 2627 2829 2a2b 2c2d 2e2f
                         3031 3233 3435 3637

But they never make it to the outgoing PPP interface - at least I can't
see them with "tcpdump" neither there nor on the incoming PPP interface
of the remote router. I even disabled IPF to be sure that it doesn't eat
those packets.

>How-To-Repeat:
Try to send packets via an IPIP tunnel and try to trace there way with
"tcpdump".

>Fix:
Sorry, I don't now.
>Audit-Trail:
>Unformatted: