Of all the gin joints in all the towns in all the world, Chia-liang Kao
had to walk into mine and say:
> I'm really sorry about this, Bill. I'll be very careful and make a
> recheck before sending out problem report next time. And really thank
> you for shouting at me instead of leaving my problem along.
Shouting is my specialty. I get a lot of practice.
> I did a `ping 192.168.100.1', and there is no response and no messages
> at all. I think the most interesting part of this is that I can see
> both of the lights on the hub blinking when I ping 192.168.100.1;
> while only the light of the other side blinks when he pings me.
What kind of hub is this?
> So we're starting to doubt the problem is the receiving function of my
> side. And we test again with `trafshow'. Then I found he does receive
> my packet and replies when I ping him, while I can only see the
> packets I sent out but no packets from his side.
>
> But sometimes it works for a tiny second, like the following:
>
> # traceroute i1
> traceroute to i1 (192.168.100.1), 30 hops max, 40 byte packets
> 1 i1 (192.168.100.1) 0.720 ms * *
Are you using any unusual networking tricks, like network address
translation or firewalling or IP aliasing? People tend to forget to
mention things like that. There are some things I'm curious about:
- What does netstat -in show? Are there any input errors? Are there
any input packets? (If the input packet counter keeps incrementing
then it has to be receiving something.)
- Do you see any suspicious messages when you do a dmesg to look at the
kernel message buffer? The vr driver should report receive errors if
it encounters any.
- If you run tcpdump on the vr0 interface (tcpdump -n -e -i vr0) can
you see the traffic from the other host? Try the following:
# arp -d 192.168.100.1
# tcpdump -n -e -i vr0 &
# ping -c 5 192.168.100.1
Show us the output.
-Bill
--
=============================================================================
-Bill Paul (212) 854-6020 | System Manager, Master of Unix-Fu
Work: wp...@ctr.columbia.edu | Center for Telecommunications Research
Home: wp...@skynet.ctr.columbia.edu | Columbia University, New York City
=============================================================================
"It is not I who am crazy; it is I who am mad!" - Ren Hoek, "Space Madness"
=============================================================================
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