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Re: Log file (fwd)

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  • Subject: Re: Log file (fwd)
  • Date: Wed, 16 May 2001 14:19:44 -0600
"Brian S. Miller" wrote:
> 
> Anne-
> Every now and then I get a "ICMP checksum is wrong" when I run a traceroute.
> 
> [root@ldm /root]# traceroute amelia.geol.iastate.edu
> traceroute to amelia.geol.iastate.edu (129.186.230.79), 30 hops max, 38 byte
> packets
> Icmp checksum is wrong
> 1 rtr-sc.icaen.uiowa.edu (128.255.140.1) 1.884 ms 0.823 ms 0.827 ms
> 2 rtr-core-lc.uiowa.edu (128.255.16.1) 1.028 ms 0.926 ms 0.926 ms
> 3 rtr-border-lc.uiowa.edu (128.255.2.129) 1.307 ms 1.071 ms 0.949 ms
> 4 aads.gw.iastate.edu (198.49.182.18) 4.053 ms 3.858 ms 3.849 ms
> 5 b31gb1.gw.iastate.edu (192.245.179.129) 4.231 ms 4.170 ms 4.054 ms
> 6 e01sr1-lan254-128.tele.iastate.edu (129.186.254.140) 4.438 ms 4.140 ms
> 4.062 ms
> 7 amelia.geol.iastate.edu (129.186.230.79) 4.237 ms 4.153 ms 4.118 ms
> 
> When I do multiple traceroute's it works great.  It is only the first one
> that I do (when I wait a few minutes between)
> Brian
> 

Hi Brian,

I've been discussing this with our system administrator.  A checksum
error usually means a corrupt packet.  He's wondering if there's a
problem in a router somewhere.  I have a few questions for you:

Do you get the checksum error if you traceroute to a machine on your own
local network and/or your campus subnetwork?

Do you get the checksum error if you traceroute elsewhere?  Try a
traceroute to my machine: imogene.unidata.ucar.edu.

You've characterized this as occuring when you first connect, but
subsequent rapid connections are ok.  What if you traceroute to one host
then immediately traceroute to a different host - does the problem
occur?

Anne

-- 
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Anne Wilson                     UCAR Unidata Program            
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                                  Boulder, CO  80307
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