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1751 Ethernet down, status shows up/up

1751 Router, 2 T-1 interfaces. This was working, it is in our lab being reconfigured for new link. Established connectivity to "core" router over test T-1 line, and a directly connected laptop on Ethernet port stated "lost connectivity". Router console had message "link down" followed by "link up". Looked at port on Router, no link lights, full-duplex, or 100Mb lights lit. Status shows link as UP/UP. I connected Router port into L2 switch, and the switch port does not come up.

Any thoughts? Is this a config issue, or did the Interface actually die?

No SmartNet on this router... :(

Hall of Fame Super Silver

Re: 1751 Ethernet down, status shows up/up


Does this router have no keepalive configured under the Ethernet interface? No keepalive will keep an Ethernet interface as reporting up/up even when nothing is connected to the interface and sounds like this may be part of your issue.

Of course getting the router to report the interface as up/down does not address the question of why it will not connect to a connected PC or to a layer 2 switch. That sounds like it might be an interface hardware problem.




Re: 1751 Ethernet down, status shows up/up

Keepalive default (10 seconds). Even with no cable attached, interface shows as Up/Up. (no status lights) Changed settings to Auto, 100Full, etc. no help.

Has anyone heard of an IOS issue that would cause this? (Running 12.4(13b))

I guess we use our last "spare", an older 1750.... hope this one keeps working...