RTACCT Utility <author>Robert Olsson <date>some_negative_number, 20 Dec 2001 <p> Here is some code for monitoring the route cache. For systems handling high network load, servers, routers, firewalls etc the route cache and its garbage collection is crucial. Linux has a solid implementation. <p> The kernel patch (not required since linux-2.4.7) adds statistics counters from route cache process into /proc/net/rt_cache_stat. A companion user mode program presents the statistics in a vmstat or iostat manner. The ratio between cache hits and misses gives the flow length. <p> Hopefully it can help understanding performance and DoS and other related issues. <p> An URL where newer versions of this utility can be (probably) found is ftp://robur.slu.se/pub/Linux/net-development/rt_cache_stat/ <p><bf/Description/ <p>The format of the command is: <tscreen><verb> rtstat [ OPTIONS ] </verb></tscreen> <p> <tt/OPTIONS/ are: <itemize> <item><tt/-h/, <tt/-help/ - show help page and version of the utility. <item><tt/-i INTERVAL/ - interval between snapshots, default value is 2 seconds. <item><tt/-s NUMBER/ - whether to print header line. 0 inhibits header line, 1 prescribes to print it once and 2 (this is default setting) forces header line each 20 lines. </itemize> </article>