Examining network communication

Because the server is a network-based application, it can be valuable to observe the network communication that it has with clients. The server itself can provide details about its interaction with clients by enabling debugging for the protocol or data debug categories, but there can be a number of cases in which it is useful to view information at a much lower level. A network sniffer, like the tcpdump tool on Linux, can be used to accomplish this.

There are many options that can be used with these tools, and their corresponding manual pages will provide a more thorough explanation of their use. However, to perform basic tracing to show the full details of the packets received for communication on port 389 with remote host 1.2.3.4, the following command can be used on Linux:

It does not appear that the tcpdump tool provides support for LDAP parsing. However, it is possible to write capture data to a file rather than displaying information on the terminal (using "-w {path}" with tcpdump), so that information can be later analyzed with a graphical tool like Wireshark, which provides the ability to interpret LDAP communication on any port.

Note that enabling network tracing generally requires privileges that are not available to normal users and therefore can require root access.