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<article>
<title>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>