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Trace Route on Linksys Routers

Several people have mentioned this so I thought I'd put up a short article about this.

On some of the old firmware for the Linksys WAG354G and also possibly the Linksys HG200 (which as far as anyone knows is a cut-down version of the Linksys WAG354G) there is a bug which causes the trace route tracert command to fail.

The main symptom of this is getting a tracert result similar to this example:

Tracing route to clarity.jolt.co.uk [195.149.21.11] over a maximum of 30 hops: 1 <1 ms <1 ms &th;1 ms 192.168.1.1 2 * * * Request timed out. 3 * * * Request timed out. 4 * * * Request timed out. 5 * * * Request timed out. 6 * * * Request timed out. 7 11 ms 12 ms 11 ms clarity.jolt.co.uk [195.149.21.11] Trace complete.




As you can see its not very useful - you're getting "Request timed out." instead of the usual information about each hop. As far as I know, this is because the router is filtering out the ICMP "TTL expired in transit" response code that the routers are sending back at each hop.

I've come across a lot of potential solutions that people have come up with to try and solve this. Usually people assume you are running some kind of firewall that is causing problems or you need to forward ports but this isn't the answer. Others have said that you need to change from PPPoA to PPPoE in the router's settings but this doesn't change anything either.

The only solution I found was to simply flash the firmware up to the latest version, which was 1.01.05 (Oct 20 2005) for me. I'm not sure if the tracert problem was a deliberate measure for security, or more likely just a bug that slipped though.

To get the latest firmware for your router you can go to the Linksys UK page - their site is a big strange so hopefully this URL will work for everyone:

Linksys Firmware Downloads

Just select your router from the list and follow Linksys's instructions about how to flash the firmware (you might want to refer to the original manual too, which you can also download).

Its probably worth noting that there is now a "WAG354G V2" on the download list that I'd not seen before. As far as I know, I have a "WAG354G V1", so I don't know if this bug exists in the V2 model. I've got no idea what changes have been made in the new model - the datasheet was in Spanish and listed the model as "WAG354G(SP)" but all of the specifications looked the same so I think it might be a Spain only model? The firmware for the V2 model hasn't had its source code released yet so I cant have a poke around until then!

Back 24.06.2006.