• Looking for some advice on using DHCP with wireless. I've run into two cases recently where if I set up a client to use DHCP it will find the AP, but DHCP never completes. However, if I set a static IP in both cases, standing in the same location, the wireless works fine. I'm sure that since DHCP is a connectionless protocol that its either timing out or the frame with the DHCP information is getting dropped somewhere. Would boosting the gain on the antenna solve the problem, or is there a better solution.

    Both cases involve using wireless to provide public Internet access, so DHCP is a must. Both cases use a Cisco 1242 AG access point. One is an outdoor solution (kind of) at a motel providing internet access to the rooms. Brick facade, but room is wood construction with a plaster ceiling. Other case is an old courthouse with 18" thick stone walls.

    Any ideas would be appreciated. Thank you in advance.


  • Its not a wireless problem. Wireless is layer 2 and doesn't distinguish between DHCP and any other upper layer protocols.

    Wire yourself to your router. Do you get an IP address from DHCP? I suspect that it is a router problem. Let us know!

  • I would just like to humbly inject that this is becoming a common problem for some reason. On a different forum this is a regular troubleshooting exercise that I go through.

    The end results are typically as Gene mentioned that you have a router/DHCP server issue. Sometimes I have resolved it by reconfiguring the scope, but in more cases than not the device had to be replaced.

  • Will definitely try that and let you know the results.

    I guess my point was that since DHCP is a UDP protocol if the frames containing the DHCP information got dropped or significantly slowed down due to going through brick/stone there is no handshaking going on to let the other side know to re-send the information. Whereas like with HTTP which uses TCP if packets are lost, there is a mechanism in place to re-request packets.


  • You can check that theory out with a packet sniffer. I have not seen that as an issue. I have had the two devices right next to each other and seen the same results. Quite strange to say the least. I even had on where the router was issuing correct DHCP scope information to wired devices but not wireless ones. Replaced the router and everything worked fine.

  • I even had on where the router was issuing correct DHCP scope information to wired devices but not to some wireless ones. The laptop which I was trying to connect some how didn't get the IP from DHCP even though I enter the WEP 128bit key correct. I changed the security settings to WPA and it worked like a charm.

Page 1 of 1
  • 1