Re: traceroute bug ?

["Gerold van Dijk" <gerold@sicon-sr.com>]

Dear Valdis et.al.,

thanks for biting! I really tested this thing thoroughly, with different 
distributions (Red Hat, SuSE 8.0 and 10.0) on different machines with the 
firewalls completely open, and without any router or switch involved: cross 
cable straight from one machine to another!

IF I ONLY CHANGE TO ANOTHER IP BLOCK (E.G. 206.253.5.64/24) OR A PRIVATE 
RANGE (E.G. 192.168.1.0/24) THE TRACEROUTE WORKS FINE! SO IT IS SPECIFICALLY 
THIS 207.253.5.0/24 BLOCK THAT DOES NOT TRACEROUTE WITHIN IT'S OWN RANGE!

Not only the subnetwork 207.253.5.64/27 but the whole class C block 
207.253.5.0/24 !?

Just to be complete: we CAN ping normally within this network!

But the traceroute simple displays "*  *  *" row after row!

Of course it is not that urgent a problem, cause what is the sense of doing 
a traceroute within your own network anyway? But I thought it might be 
useful to report this strange thing!

Thank you all for your time!

Regards,

Gerold H. van Dijk

Research & Training Manager

SICON; Suriname Information &
Communication Network

Verl.Gemenelandsweg 163
Paramaribo, Suriname
South America

(+597)    464791
(+597)    491510 (fax)
(+597)(0) 8579216 (gsm)

gerold@sicon-sr.com
gerold_vandijk@hotmail.com



On Fri, 27 Jan 2006 15:38:23 -0300, Gerold van Dijk said:
> Why can I NOT do a traceroute specifically within my own (sub)network
>
> 207.253.5.64/27
>
> with any distribution of Linux??

OK.. I'll bite.  What happens when you try?  And why are you posting here - 
is
there *any* evidence that there is a Linux kernel bug involved?

The output of 'ifconfig' and 'netstat -r -n' would likely be helpful, as 
would
proof that the host(s) you're tracerouting from and to are *not* running a
firewall that interferes with the way traceroute functions. (It's amazing 
how
many people block all ICMP, then wonder why traceroute doesn't work... ;)

Watching the wire with 'tcpdump' and/or 'ethereal' can also help....

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