Cisco IOS Upgrade issue

[zkuthubdeen]

We hve upgraded one of router IOS ver to 12.4 & had a following problem.

WAN interface is configured before as 192.168.1.1/30 after upgrading to 12.4 it has change to 192.168.1.1/24. if we change manually to 192.168.1.1 /30 it is giving bad subnet mask /30. Please advice

[mohammedmahmoud · Accepted solution]

hi,

Its so weird, kindly check that these 2 commands are in the configuration:

ip subnet-zero

ip classless

Hope that helps.

[zkuthubdeen]

Thank you mohammed for your reply. In fact we have tried 'ip classless', but no luck.We ll try ip 'subnet-zero' and let you know the outcome. mean time please can you advice alternative troubleshooting if above solution didnt work. Appricated your support

Zaheed

[mohammedmahmoud]

Zaheed,

Can you please issue show version to make sure that the router loaded with the new IOS.

[zkuthubdeen]

Moahmmed,

After upgrading we have checked show version and router has loaded with correct IOS.But at the movement we rollback to old version, pls find below current (with old IOS) show version out put,

DialNet-Main-Router#sh ver

Cisco Internetwork Operating System Software IOS (tm) 3700 Software (C3725-I-M), Version 12.3(15a), RELEASE SOFTWARE (fc2) Technical Support: http://www.cisco.com/techsupport Copyright (c) 1986-2005 by cisco Systems, Inc.

Compiled Fri 22-Jul-05 00:22 by dchih

Image text-base: 0x60008AF4, data-base: 0x60DEE000

ROM: System Bootstrap, Version 12.2(8r)T2, RELEASE SOFTWARE (fc1)

ROM: 3700 Software (C3725-I-M), Version 12.3(15a), RELEASE SOFTWARE (fc2) DialNet-Main-Router uptime is 2 weeks, 1 day, 21 hours, 1 minute System returned to ROM by power-on System image file is "flash:c3725-i-mz.123-15a.bin"

cisco 3725 (R7000) processor (revision 0.1) with 251904K/10240K bytes of memory.

Processor board ID JHY0846K0U0

R7000 CPU at 240MHz, Implementation 39, Rev 3.3, 256KB L2 Cache Bridging software.

X.25 software, Version 3.0.0.

2 FastEthernet/IEEE 802.3 interface(s)

4 Serial network interface(s)

DRAM configuration is 64 bits wide with parity disabled.

55K bytes of non-volatile configuration memory.

31360K bytes of ATA System CompactFlash (Read/Write) Configuration register is 0x3922

DialNet-Main-Router#

Please advise

Zaheed

[Richard Burts]

While you are running the old IOS and it works correctly there is not much advice or solution that we can find. If you load the new IOS it would be helpful to post the output of show version, and the content of the interface configuration. Perhaps attempt the configuration, capture and post the terminal session including the configuratin command and the error message.

In my experience the bad mask error message is usually the result of attempting to configure addresses in subnet zero and having ip subnet-zero not enabled (it has been enabled by default for a very long time) or it is the result of attempting to configure an address that is the subnet address or the subnet broadcast address.

So if we knew some specifics about what you are attempting to configure it would help us understand the problem.

HTH

Rick

[zkuthubdeen]

Hi Rick,

Thank you for your support.

Finally its working with ip subnet-zero command. many thanks to you and mohammed