From: Christian Hammers <ch@westend.com>
To: linux-kernel@vger.kernel.org
Subject: icmp_ratelimit seems to be too low (related to NAT?)
Date: Mon, 5 May 2003 11:35:23 +0200 [thread overview]
Message-ID: <20030505093523.GE15625@westend.com> (raw)
Hello
icmp_ratelimit has, as of kernel 2.4.20, a default of 100 (which unit
btw?). This seems to be too low as I have packet loss when doing two
"mtr" to the same 4 hops away host simultaneously. As this suggerates
packet loss on the network to the administrator, a too low limit will
certainly annoy network admins as it gives wrong information.
My tests gave the following results:
src. linux --> SNAT'ing linux router --> cisco1 --> cisco2 --> dst. linux
On the src linux host I opened _two_ mtr at the same time and watched
the packet loss at the first host after 30 rounds (seconds).
icmp_ratelimit | loss at hop1 for both mtr
0 0
10 0
20 0
40 0
80 34% and 37%
100 44% and 57% (default)
160 64% and 75%
320 87% and 83%
999 100% and 100%
For 2*(4*icmp_request + 4*icmp_timeexceeded/reply) = 16 packets per
second the loss seems to be a bit high at the default value of 100.
Is this related to any other setting? Maybe NAT?
My /proc/net/ip_conntrack only has 1200 lines and the max in
/proc/sys/net/ipv4/ip_conntrack_max is 32767.
bye,
-christian-
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Technik CISCO Systems Partner - Authorized Reseller
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next reply other threads:[~2003-05-05 9:23 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-05-05 9:35 Christian Hammers [this message]
2003-05-05 14:53 ` icmp_ratelimit seems to be too low (related to NAT?) Randy.Dunlap
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