On 29/10/2012 13:26, Jerry Geis wrote: >> ck your duplex. I have had two recent problems with duplex: >> >> One, with a Cisco router - it auto-negotiated every time to half duplex, even >> though it really -was- full. Use mii-tool to find out. >> Just a note, auto-negotiation of 10/100 links will not work reliably unless both sides of the link are set to auto-negotiate. If one side is set to 100/full, and the other side is set to auto negotiate, then it will try to negotiate, the side that is hard coded 100/full will _NOT_ negotiate and negotiation will fail, the side that was set to auto negotiate will fail back to a 'fail-safe' 10/half duplex link. My rule of thumb, static link (e.g. those to servers, inter switch links, switch to router links etc...) should just be hard coded. Links that might have a variety of devices connected to them, e.g. the access layer ports - set them to auto-negotiate. -- Regards, Giles Coochey, CCNA, CCNAS NetSecSpec Ltd +44 (0) 7983 877438 http://www.coochey.net http://www.netsecspec.co.uk giles at coochey.net