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Community Member

2600 series router can't detect interfaces

my 2600 series router can't detect it's interfaces both serial and fastethernet.when i enter the command interface fa0/0 or fa0/1 or interface s0/0, in global config mode. it returns an invalid command output. i installed a new serial port module so that i can reload a new ios via tftp by connecting it to another router, but it still did not detect the new card. anyone with an idea on what to do? the warranty period has elapsed. so i can't return it to my the cisco reseller i bought it from.

Cisco Employee

Re: 2600 series router can't detect interfaces

Hi Friend,

Somehow I don't think all ports can go bad at a same time and hardware failure should atleast let you enter into interface config mode.

Can you just try entering command "interface fa0" or "interface s0"



Re: 2600 series router can't detect interfaces


can you share output of "show version" and "show ip interface brief" command from this router?

Re: 2600 series router can't detect interfaces

I had the same problem one year ago. I bought a used 2620 from ciscokit, but when i received it, I can't see any interface by typing "show ver" and "show ip int brief":

Cisco Internetwork Operating System Software

IOS (tm) C2600 Software (C2600-IS-M), Version 12.0(21a), RELEASE SOFTWARE (fc1)

Copyright (c) 1986-2002 by cisco Systems, Inc.

Compiled Sat 02-Feb-02 02:01 by nmasa

Image text-base: 0x80008088, data-base: 0x808FA740

ROM: System Bootstrap, Version 12.1(3r)T2, RELEASE SOFTWARE (fc1)

Router uptime is 4 minutes

System restarted by power-on

System image file is "flash:c2600-is-mz.120-21a.bin"

cisco 2600 (MPC860) processor (revision 0x600) with 53248K/12288K bytes of memory.

Processor board ID JAD0601066D (266423927)

M860 processor: part number 0, mask 49

Bridging software.

X.25 software, Version 3.0.0.

32K bytes of non-volatile configuration memory.

16384K bytes of processor board System flash (Read/Write)

Configuration register is 0x2102

Router>show ip interface brief

Interface IP-Address OK? Method Status Protocol


Please check the above info and see whether it is exactly the same case you have. If so, let me know, I can tell you how to fix.



Community Member

Re: 2600 series router can't detect interfaces

it's the same thing, please can u share your methods.( please note when i entered the show controllers command it returns a blank output).

thank you.... hope to hear from u.


Community Member

Re: 2600 series router can't detect interfaces

Are you sure the version of IOS on your router supports the interfaces?

The 26xx w/ fast ethernet can boot earlier IOSes designed for ethernet versions but it won't recognise the fast ethernet hardware.

You can always upload a new image onto the device over the serial line through rommon. Just remember to set the serial speed to 115200 or you'll be waiting a while.

Community Member

Re: 2600 series router can't detect interfaces

This is pureply in IOS related issues. Pls. try the following options to upload a new IOS suitable IOS which can resolve the present issues.

usage: tftpdnld [-r]

Use this command for disaster recovery only to recover an image via TFTP.

Monitor variables are used to set up parameters for the transfer.

(Syntax: "VARIABLE_NAME=value" and use "set" to show current variables.)

"ctrl-c" or "break" stops the transfer before flash erase begins.

The following variables are REQUIRED to be set for tftpdnld:

IP_ADDRESS: The IP address for this unit

IP_SUBNET_MASK: The subnet mask for this unit

DEFAULT_GATEWAY: The default gateway for this unit

TFTP_SERVER: The IP address of the server to fetch from

TFTP_FILE: The filename to fetch


PS1=rommon ! >







You can use the XMODEM option to get the new IOS uploaded on the router.


Community Member

Re: 2600 series router can't detect interfaces

Dear brother, pls read this URL link article, and update me.

Thanks and kind regards, AK

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