I am posting this here because RH Installation support
suggest that it may be a bug.
My original posting is this:-
With Redhat 5.1 and 5.2, we have no problem telneting to
3Com Office Connect routers. With 6.0, we can telnet to
other hosts but not to 3Com OC routers. We have tried 3
different routers and 4 different installations of RH 6.0.
Using a packet analyzer, the problem looks like the fact
that the structure of the SYN packet to start the
conversation is larger on 6.0 than 5.x. On 6.0, the
diffences appear to be that the SYN flag is a Handshake
Request (A002) and a larger number of Option bytes and on
5.x, the SYN flag is a Handshake Request (6002) and only 4
byes of Option data.
I have included the two packet traces; the one with just a
single packet is the RedHat 6.0 - it repeats the packet a
number of times, and the other one is from RedHat 5.1.
Can you tell me what I need to change to get this to work.
We have the latest firmware versions in the 3Com boxes
Does the new telnet version in rawhide (or the 6.2 beta) fix this?
Closed for lack of input.
The problem is caused by the tcp_timestamps in /proc/sys/net/ipv4. 3Com routers
cannot handle timestamped ip packets. By disabling this, you can successfully
telnet a 3Com router. However, 3com don't really make routers any more.