[olug] Ping Is Broken

[Aric Aasgaard]

Does 
traceroute -i eth0 -I 208.67.222.222
using ICMP

or using UDP 
traceroute -i eth0 208.67.222.222

Work?

-----Original Message-----
From: olug-bounces at olug.org [mailto:olug-bounces at olug.org] On Behalf Of Rob
Townley
Sent: Friday, October 09, 2009 11:45 AM
To: netdev at vger.kernel.org
Cc: CentOS mailing list; Omaha Linux User Group
Subject: Re: [olug] Ping Is Broken

ping -I is broken

The following deals with bug in ping that made it very difficult to set up a
system with two gateways.

Demonstration that *ping -I is broken*. When specifying the source
interface using -I with an *ethX* alias and that interface is not the
default gateway
interface, then ping fails. When specifying the interface as an ip address,
ping works. Search for "Destination Host Unreachable" to find the bug.


eth*0* = 4.3.2.8 and the default gateway is accessed through a different
interface eth*1*.
eth*1* = 192.168.168.155 is used as the device to get to the default
gateway.
*FAILS *: ping *-I eth0* 208.67.222.222
*WORKS*: ping *-I 4.3.2.8* 208.67.222.222
*WORKS*: ping *-I eth1* 208.67.222.222
*WORKS*: ping *-I 192.168.168.155* 208.67.222.222

The following are actual results which can be reproduced from an up-to-date
Fedora 11 or CentOS 5.3 box. Caused a very very long episode of frustration
when setting up multi gatewayed systems.


* ping using eth0 *:

ping -c 2 -B -I  eth0 208.67.222.222
PING 208.67.222.222 (208.67.222.222) from 4.3.2.8 eth0: 56(84) bytes of
data.