Cisco router interface not FDX


I have a cisco 1841 router and one fastethernet interface connected to a switch onlu half duplex... not full.


See the attached code.

interface FastEthernet0/1
 description $ETH-WAN$$FW_OUTSIDE$
 ip address xxxxxxxxxxxxxxxx
 ip access-group 103 in
 ip verify unicast reverse-path
 no ip redirects
 no ip unreachables
 no ip proxy-arp
 ip nbar protocol-discovery
 ip flow ingress
 ip flow egress
 ip nat outside
 ip virtual-reassembly max-reassemblies 75
 speed 100
 snmp trap ip verify drop-rate
 no mop enabled
 crypto map cmap-dele

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dazm_2000Connect With a Mentor Commented:
You need to make the switch and the router interface the same ie

Both 100/full or
both auto / auto

The issue you have right now is because you have a mismatch of fixed and auto configuration.

Change the 1841 to auto speed and auto duplex or if its easier change the switch to 100 full and duplex full.

On the 1841 become enabled


conf t
int FastEthernet0/1
speed auto
duplex auto
wri mem

Just bear in mind that if you aren't plugged into the console port you might cut yourself off if the line protocol on the FastEthernet0/1 drops as you are making your changes if you are connecting to the router via connectivity that uses FastEthernet0/1

Cheers daz
Can you confirm your switchport is set for  - speed 100 and duplex full?.

If you cannot manage the switch then set your 1841 interface to

speed auto
duplex full

Please note the cable from the 1841 to the switch should also be a straight through cat5

Cheers darren
heze54Author Commented:

The switch is auto port 10/100 fdx

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heze54Author Commented:
I´ll do those changes.....
heze54Author Commented:
changes done

reboot is  requiered?
heze54Author Commented:
Lovely...It works

Thanks a lot
Cool glad to be of assistance
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