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Errors on a 3640 router

We have a router outside a firewall that seems to be the source of connectivity issues. FA0/0 connects to a firewall that is under our control, FA0/1 connects to a network that is outside our control. The errors are on FA0/0. SSH sessions to this router are slow, as are ssh sessions to servers behind this router. Some NTP traffic going through the router seems to be dropping.

Here is the show int:

sh int fa0/0

FastEthernet0/0 is up, line protocol is up

Hardware is AmdFE, address is 0010.7b84.2fc0 (bia 0010.7b84.2fc0)

Internet address is

MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

reliability 255/255, txload 1/255, rxload 2/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Full-duplex, 100Mb/s, 100BaseTX/FX

ARP type: ARPA, ARP Timeout 04:00:00

Last input 00:00:00, output 00:00:00, output hang never

Last clearing of "show interface" counters 00:58:47

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue: 0/40 (size/max)

5 minute input rate 971000 bits/sec, 189 packets/sec

5 minute output rate 138000 bits/sec, 149 packets/sec

696420 packets input, 467071241 bytes

Received 1 broadcasts, 0 runts, 0 giants, 0 throttles

341 input errors, 0 CRC, 0 frame, 341 overrun, 0 ignored

0 watchdog

0 input packets with dribble condition detected

550225 packets output, 110026505 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

0 babbles, 0 late collision, 0 deferred

0 lost carrier, 0 no carrier

0 output buffer failures, 0 output buffers swapped out

This is on a 3640 running 12.4(8).

What could be at the source of the problems?


Re: Errors on a 3640 router

Lot of input errors are seen. Reason could be bad cabling, Duplex mismatch or bad NICS

Try changing the cable connecting to your firewall.



Re: Errors on a 3640 router


This interface has had 341 'Input errors'. An input error includes runts,

giants, no buffer, CRC, frame, overrun, and ignored counts. Other input-related

errors can also cause the input error count to be increased. Some datagrams can

have more than one error. Therefore, this sum may not be equal to the sum of

enumerated input error counts.

341 'overruns' have been reported, 0.04894% of the total input traffic.

This is because, the input rate exceeds the ability of the receiver to handle


So as said below you can try by changing cable or duplex settings....

Rate if it does,