Cisco IP accounting support provides basic IP accounting functions. By enabling IP accounting, users can see the number of bytes and packets switched through the software on a source and destination IP address basis. Only transit IP traffic is measured and only on an outbound basis; traffic generated by the software or terminating in the software is not included in the accounting statistics. To maintain accurate accounting totals, the software maintains two accounting databases: an active and a checkpointed database.
Cisco IP accounting support also provides information identifying IP traffic that fails IP access lists. Identifying IP source addresses that violate IP access lists alerts you to possible attempts to breach security. The data also indicates that you should verify IP access list configurations. To make this functionality available to users, you must enable IP accounting of access list violations using the ipaccountingaccess-violations interface configuration command. Users can then display the number of bytes and packets from a single source that attempted to breach security against the access list for the source destination pair. By default, IP accounting displays the number of packets that have passed access lists and were routed.
Show and Clear Commands for IOS Sockets
The Show and Clear Commands for IOS Sockets feature introduces the showudp, showsockets, and clearsocketscommands. These new commands are useful for monitoring and managing the Cisco IOS Socket library.
In Cisco IOS software, sockets are a per process entity. This means that the maximum number of sockets is per process and all sockets are managed on a per process basis. For example, each Cisco IOS process could have a socket with file descriptor number 1. This is unlike UNIX or other operating systems that have per system file descriptor allocations.
The showand clear commands operate on a per process basis to be consistent with the current functionality. Thus, any action taken by the commands will be applicable only to a particular process at a time as selected by the process ID entered on the CLI.
Many applications have a need for show and clearcommands, which primarily aid in debugging. The following scenarios provide examples of when these commands might be useful:
The application H.323 is using sockets for voice calls. According to the current number of calls, there is still space for more sockets. However, no more sockets can be opened. You can now use the the showsockets command to find out if the socket space is indeed exhausted or if there are unused sockets available.
An application is waiting for a particular socket event to happen. A UDP segment was seen, but the application never became active. You can use the showudp command to display the list of events being monitored to determine if a UDP socket event is being monitored or if the socket library failed to activate the application.
An application wants to forcibly close all the sockets for a particular process. You can use the clearsockets command to close both the sockets and the underlying TCP or UDP connection or Stream Control Transmission Protocol (SCTP) association.
