Solved: C1841 fa0/0 up when unplug LAN cable

t.sriwetchasin · ‎12-20-2008

When I unplug LAN cable from interface fa0/0 why interface still up but protocol down ?

It is default ? or we can set ?

Thank you in advance.

scottmac · ‎12-20-2008

If you have keepalives disabled, then the link will stay up.

Check your config, under that interface, for a "no keepalive" statement

Also make sure you are looking at the right interface ....

Good Luck

Scott

View solution in original post

Richard Burts · ‎12-22-2008

teerapon

It is the default behavior of IOS routers such as the 1841 that if the FastEthernet interface is not plugged into some device then the interface will show as interface up and line protocol is down.

HTH

Rick

HTH

Rick

View solution in original post

scottmac · ‎12-20-2008

If you have keepalives disabled, then the link will stay up.

Check your config, under that interface, for a "no keepalive" statement

Also make sure you are looking at the right interface ....

Good Luck

Scott

t.sriwetchasin · ‎12-21-2008

Thank you Scott.

So, If I used "no keepalive" command under int fa0/0, interface and protocol will up both but I did not plug LAN cable into that interface.

I also check with another new router C1841. After completed boot and no shutdown the fastEthernet interface. FastEthernet interface is up without LAN cable connected.

It may be default of router? and How to make it down when we did not plug the LAN cable into interface ?

Environment

C1841

IOS c1841-ipbasek9-mz.124-23.bin

Thank you.

Richard Burts · ‎12-22-2008

teerapon

It is the default behavior of IOS routers such as the 1841 that if the FastEthernet interface is not plugged into some device then the interface will show as interface up and line protocol is down.

HTH

Rick

HTH

Rick