Upgrade Cisco IOS on the 877W

Cisco LogoYesterday it struck me I was using a less secure wireless setup while the more secure was just a simple configuration change away. While adjusting the configuration I noticed the software version was pretty dated because my last IOS update (12.4.24T1) was from May 2009. To stay current I decided to upgrade my home router.

12.4.24T8 is the latest IOS in the 12.4T series. This version was released on 19 September 2012. I don’t have enough flash capacity to store the new 15.1.4 release, so I will stick with the 12.4.24 release. So I downloaded c870-advipservicesk9-mz.124-24.T8.bin from Cisco.

I have described the steps below so it will be a walk in the park next time.

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Improve wireless security on the 877W

cisco-877w-frontI just discovered my three year old Cisco wireless router was configured to do WPA encryption instead of the more secure WPA2 version, which is the standard nowadays. WPA uses TKIP (Temporal Key Integrity Protocol) while WPA2 is capable of using TKIP or the more advanced AES algorithm. Doing a search on Google it appears it’s just a IOS configuration option.


interface Dot11Radio0
no ip address
encryption vlan 2 mode ciphers tkip


interface Dot11Radio0
no ip address
encryption vlan 2 mode ciphers aes-ccm

If the option is not there, your IOS version does not support it. I’m currently using: C870 Software, Version 12.4(24)T1 (c870-advipservicesk9-mz.124-24.T1.bin).

Intermittent WiFi signal

I experienced a intermittent WiFi signal lately on multiple devices. Since I haven’t touched my router configuration for a while it had to be something different. Some time passed before I realized it could be a neighbor who was using the same frequency I was using. Looking into my router configuration it turned out I was using a fixed frequency (2462).  Below are the frequencies that can be configured.

Channel 1 : 2412 Mhz 11g
Channel 2 : 2417 Mhz 11g
Channel 3 : 2422 Mhz 11g
Channel 4 : 2427 Mhz 11g
Channel 5 : 2432 Mhz 11g
Channel 6 : 2437* Mhz 11g
Channel 7 : 2442 Mhz 11g
Channel 8 : 2447 Mhz 11g
Channel 9 : 2452 Mhz 11g
Channel 10 : 2457 Mhz 11g
Channel 11 : 2462 Mhz 11g
Channel 12 : 2467 Mhz 11g
Channel 13 : 2472 Mhz 11g

While thinking about which new frequency to choose I figured out there is an option to choose the least congested. That’s what I need in an area where there are at least 30+ different access-points.

router#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
router(config)#interface Dot11Radio0
router(config-if)#channel 2457
router(config-if)# channel ?
<1-2472>         One of: 1 2 3 4 5 6 7 8 9 10 11 12 13 2412 2417 2422 2427
2432 2437 2442 2447 2452 2457 2462 2467 2472
least-congested  Scan for best frequency

router(config-if)# channel least-congested

Now every WiFi enabled device in the house is happy again.