[nSLUG] Router won't do 100mbps locally

Dop Ganger nslug at fop.ns.ca
Thu Feb 4 11:18:47 AST 2010

On Thu, 4 Feb 2010, Mike Spencer wrote:

> So, with ethtool, I force both cards to "autoneg off duplex full speed
> 100".  The blinkenlights on the router go into continuous twiddle
> mode.  No packets are detected by tcpdump.  So the cards are trying to
> establish a 100Mbps connection with the router at the Ethernet level
> (right?)  and failing (right?).

My vote is for duff cables too, with an outside chance of corrosion on the 
connectors on the NIC or cable. Try a crossover cable between the two 
machines and see if that works to rule out the switch?

Autonegotiation isn't necessarily all it's cracked up to be, either. The 
general recommendation for most applications in the enterprise world is to 
hard code the speed on the NIC and the switch rather than relying on 

Cheers... Dop.

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