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TL-WA901ND 300Mbps Wireless N Access Point User Guide
Figure 4-33 Diagnostic
Diagnostic Tools - Click the radio button to select one diagnostic tool
•Ping - This diagnostic tool troubleshoots connectivity, reachability, and name resolution to a given host or gateway by using the Internet Control Message Protocol (ICMP) protocol's mandatory Echo Request datagram to elicit an ICMP Echo Response from a host or gateway. You can use ping to test both numeric IP address or domain name. If pinging the IP address is successful, but pinging the domain name is not, you might have a name resolution problem. In this case, ensure that the domain name you are specifying can be resolved by using Domain Name System (DNS) queries.
•Traceroute - This diagnostic tool determines the path taken to a given host by sending Internet Control Message Protocol (ICMP) Echo Request messages with varying Time to Live (TTL) values to the destination. Each gateway along the path is required to decrement the TTL in an IP packet by at least 1 before forwarding it. Effectively, the TTL is a maximum link counter. When the TTL on a packet reaches 0, the gateway is expected to return an ICMP Time Exceeded response to your device. Traceroute determines the path by sending the first Echo Request message with a TTL of 1 and incrementing the TTL by 1 on each subsequent transmission until the target responds or the maximum number of hops is reached. The maximum number of hops is 20 by default and can be specified in the field "Traceroute Max TTL". The path is determined by examining the ICMP Time Exceeded messages returned by intermediate gateways and the Echo Reply message returned by the destination. However, some gateways do not return Time Exceeded messages for packets with expired TTL values and are invisible to the traceroute tool. In this case, a row of asterisks (*) is displayed for that hop.
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