How to wireless Internet access to the problem of IP address

In fact, the failure of DHCP (Dynamic Host Control Protocol) after wireless negotiation is a common problem. Wireless negotiation establishes a data link. Once the connection is established, the base station can transmit and receive data frames. At this point, most base stations send a DHCP request: A UDP packet is sent from 67 to 68 ports. If a local area network can access the DHCP server, the server evaluates and responds to the request, usually assigning an IP address to the requesting base station. So if wireless Internet access does not have access to IP address, what is the problem?

First, the base station cannot establish a connection with the access point. Even if the signal is strong, the access point can reject the base station link or the identity request. For example, an access point may be too busy or a supported speed rate or security parameter mismatch (for example, the base station may not have the correct WEP key). Check that your wireless card does not match the access point's functionality and security settings and use your Access point log to verify that a contact intermediate system (IS) has been established.

Second, the access point may still not be connected to the base station where the connection is to be established. For example, an access point may be set up with a Mac access control table, without an IP address containing a base station. or the base station may not be identified by WPA-PSK or WPA (802.1X). Using the WPA-PSK protocol, a base station that did not present the correct preshared key looked like it was connected, but never got an IP address. With WPA (802.1X), a base station may be able to contact for approximately 1 minutes and disconnect after a 802.1X swap failure. Carefully observe the connection status of the base station and repeatedly check the identification settings. If you use Windows XP SP2, use the "netsh ras set tracing" command to start the Wzctrace.log Network Trace logging feature.

Third, the base station that is actually connected to an access point is still unable to connect to the DHCP server. The wireless router usually has a built-in DHCP server, but that server may be shut down. The wireless access point typically requires that the DHCP server be located somewhere in the upper part of the Ethernet connection to the access point. Verify that there is a DHCP server in your local area network (or virtual local area network) and access to that DHCP server from your access point. Another possibility (unlikely) is that the DHCP server is blocked by the wireless base station's personal firewall or blocked by the IP filter of the access point. If you suspect a DHCP problem, look at the data packets that use Ethernet, including the packets on the base station and the packets on the wired LAN. On the Windows platform, when you observe, you can use the "Ipconfig/release" and "ipconfig/renew" commands to send DHCP repeatedly.

Finally, the DHCP server must be willing to release an IP address to the base station. We usually think this is certain, but if you exclude other possibilities, check the logs on your DHCP server to verify that the base station's request was received and that the address was assigned. For example, a DHCP server that is typically busy may temporarily reject a request when an IP address segment is exhausted.

The first and second issues mentioned above are the most common. Especially if your base station is running the Windows XP SP2 operating system and has an enabled/active connection, but if the report says the connection is restricted or not connected, then you are likely to encounter a second problem.