Modern WLANs incorporate various technologies to help secure the data on the WLAN: incorrect configuration of any of these can prevent communication. Some of the most common settings that are configured incorrectly include: the SSID, authentication and encryption.
1. The SSID is a case-sensitive, alpha-numeric string up to 32-characters. It must match on both the AP and client. If the SSID is broadcast and detected, this is not an issue. If the SSID is not broadcast, it must be manually entered onto the client. If the client is configured with the wrong SSID, it will not associate with the AP. Additionally, if another AP is present that is broadcasting the SSID, the client may automatically associate to it.
2. On most APs open authentication is configured by default, allowing all devices to connect. If a more secure form of authentication is configured, a key is necessary. Both the client and the AP must be configured with the same key. If the keys do not match, authentication will fail and the devices will not associate.
Encryption is the process of altering the data so that it is not usable by anyone without the proper encryption key. If encryption is enabled, the same encryption key must be configured on both the AP and the client. If the client associates with the AP but can not send or receive data, the encryption key may be the issue.
Determining if your computer is obtaining the correct IP address
If the physical connection to the wired or wireless host appears to be connecting as expected, then check the IP configuration of the client.
The IP configuration can have a major impact on the ability for a host to connect to the network. An integrated router, such as the Linksys wireless router, acts as a DHCP server for local wired and wireless clients and provides IP configuration, including the IP address, subnet mask, default gateway, and possibly even IP addresses of DNS servers. The DHCP server binds the IP address to a client's MAC address and stores that information in a client table. On the home Linksys wireless router, this table can be examined through the Status | Local Network page in the GUI.
The client table information should match the local host information, which can be obtained from the ipconfig /all command. Additionally, the IP address on the client must be on the same network as the LAN interface of the Linksys device. The LAN interface of the Linksys device should be set as the default gateway. If the client configuration information does not agree with information in the client table, the address should be released (ipconfig /release) and renewed (ipconfig /renew) to form a new binding.
If both the wired and wireless clients are obtaining the correct IP configuration, and can connect to the Linksys device, but are unable to ping each other, the problem is most likely occurring on the Linksys device. Check all configurations on the Linksys device to ensure no security restrictions could be causing the issue.