Why "ping" can't recognize the "icmp: echo reply" message ?

Why "ping" can't recognize the "icmp: echo reply" message ?

Post by Vict » Fri, 01 Feb 2002 04:24:12



Hi, all

After having made some modification on a Network driver, I found that
the ping program on another machine can't recognize the "icmp: echo
reply" message from this driver.  Yes, I monitered the packets by
tcpdump and it shows the "icmp: echo reply" message was received.  Why
the "ping" program can't recognize them?

And I also found that the DF flag  of "icmp: echo reply" message was
not set, how can I force the TCP/IP layer to set that flag?

Thanks

Victor

 
 
 

Why "ping" can't recognize the "icmp: echo reply" message ?

Post by Tauno Voipi » Fri, 01 Feb 2002 04:39:01



Quote:> Hi, all

> After having made some modification on a Network driver, I found that
> the ping program on another machine can't recognize the "icmp: echo
> reply" message from this driver.  Yes, I monitered the packets by
> tcpdump and it shows the "icmp: echo reply" message was received.  Why
> the "ping" program can't recognize them?

> And I also found that the DF flag  of "icmp: echo reply" message was
> not set, how can I force the TCP/IP layer to set that flag?

ping attempts by default to resolve the name of the other party. It may
ignore the replies if it cannot handle the reverse name resolution.

Try pinging numerically with ping -n.

Tauno Voipio