Re: [LARTC] Why 'ping' only succeed in one direction?

[Ramin Alidousti <ramin@UU.NET>]

On Wed, May 30, 2001 at 04:40:54PM +0800, shen jing wrote:

> > Thank you very much.
> 
> I've checked the file , they have the following content:
> 
> /proc/sys/net/ipv4/conf/all/rp_filter       :    1
> /proc/sys/net/ipv4/conf/default/rp_filter:    0
> /proc/sys/net/ipv4/conf/eth0/rp_filter:        0
> /proc/sys/net/ipv4/conf/lo/rp_filter:            0
> 
> the ip route  says:
> 
> [root@cad166 lo]# ip route
> 192.168.1.0/24 dev eth0  proto kernel  scope link  src 192.168.1.1
> 210.32.131.0/24 dev eth0  proto kernel  scope link  src 210.32.131.166
> 127.0.0.0/8 dev lo  scope link
> default via 210.32.131.1 dev eth0
> default via 210.32.131.1 dev eth0  src 210.32.131.166  metric 1
> [root@cad166 lo]#
> 
> I don't understand what's  the files under  all/  and default/ for.
> And the tcpdump on linuxbox and snoop on Sun both shows
> icmp echo request and icmp echo reply has been received.
> But why 'ping 210.32.131.97' always show nothing when executed
> on 192.168.1.8?

It might be that the linux router sends you ICMP redirects as the
forwarding interface is the same as the incoming interface but
it also should've happened when you "ping 192.168.1.8 "on Sun-1.

How did you create eth0:0? With "ifconfig" or "ip addr"?
What is the output of "ifconfig -a"? Do you see 210.32.131.166
as eth0:0 (meaning that it is an alias? If you'd created it with
"ip addr" you shouldn't have had ":0" there.

I'd suggest you to send the output of tcpdump when you 
"ping 210.32.131.97" on Sun-2 to see what is going on.

Ramin


> 
> 
> 
> James Shen

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