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3Com DHCP Issues

bretcollins
Level 1
Level 1

We have a Cisco Wireless network using a variety of Cisco Access Points (1231G, 1120B, 1121G, Light Weight 1010). We are using 3Com wireless bridges to connect or older printers to the wireless network. I upgraded the 3com devices to firmware 2.1.7 so they would support LEAP and I was able to get several working. Depending on where I place them (what AP they connect to) some of them won't get a DHCP address and the printers connected to them won't get a DHCP address. We are using Windows 2000 server DHCP. Our other devices have no problem getting DHCP on the same wireless networks. If I hardcode an address on the bridge and the printer then everything works. Does anyone have any ideas why DHCP wouldn't work when it works with other devices? Once I manually assign it an address it works so I don't think it's a LEAP issue, and it works on some of the AP's (mostly the older ones). Thanks for any suggestions.

6 Replies 6

globalnettech
Level 5
Level 5

Hello,

a couple of questions:

Can you specify which access points do work when connecting the 3COM's, that is, with which AP's your devices do get a DHCP address ? Which IOS versions are the successful AP's runing, and which the ones that are not working ? Also, did this work before upgrading the firmware ?

Regards,

GNT

sorry for the delayed response.

The 1120B, 1121G and 1231G access points are all running 12.3.8-JA2. The bridges seem to be working with all of those models. The light weight access points are all running 3.2.78.0 and DHCP does not work with those APs.

Before upgrading the firmware on the 3Com's they did not support LEAP so they did not work at all. Thanks

I upgraded our wireless lan controller to 4.0.155.5 but the problem still persists.

I kind of fixed this problem. The 3Com bridges have a setting for client mode. There are two options "support multiple wired ethernet clients" or "support single wired ethernet client". If you choose the support single wired ethernet client option you can choose the MAC option with three choices, capture, dynamic or built-in. I tested all of these settings and found that DHCP works if the bridge is set to support single wired ethernet client with the mac option set to disabled. That fixed the original problem. The problem I have now is that I can no longer get to the web interface page of the bridge so if I need to make any changes I have to plugin to the ethernet port.

All said these bridges have been nothing but a huge pain. Is there a recommended device to enable non-wireless clients (like printers) using LEAP? Thanks.

I'm having similar issues with the 3Com bridges. In fact, I haven't found a good bridge on the market that works well with Cisco lightweight using enterprise class authentication. My latest issue is that the 3Com bridge seems to disassociate every 30 seconds and then reassociate. 3Com support hasn't been the best as they don't really resolve anything and they update their firmware very slowly and with only a couple fixes per release.

We ended up running cable to replace all of the 3Coms. We never got a resolution and we couldn't continue spending so much time trying to get them to work.

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