From: "René Pfeiffer" <lynx@luchs.at>
To: netfilter@lists.netfilter.org
Subject: Re: ICMP types to allow
Date: Thu, 22 Dec 2005 01:29:05 +0100 [thread overview]
Message-ID: <20051222002905.GI25728@nightfall.luchs.at> (raw)
In-Reply-To: <FAC4E024BF776842876169173CE2F01313B722@mailbox.vikus.com>
[-- Attachment #1: Type: text/plain, Size: 957 bytes --]
On Dec 21, 2005 at 1336 -0500, Derick Anderson appeared and said:
>
> After reading the ICMP state machine section of the Netfilter tutorial
> [http://iptables-tutorial.frozentux.net/iptables-tutorial.html#ICMPCONNE
> CTIONS] it appears that ICMP traffic related to existing TCP and UDP
> connections falls under the RELATED,ESTABLISHED rules.
This is true. However you need some inbound ICMP in order to support
things like Path MTU discovery. I often allow the inbound ICMP message types
time-exceeded, destination-unreachable and parameter-problem. This
covers messages that deal with packet fragmentation. You might want to
disallow some of the destination-unreachable messages.
Best,
René.
--
)\._.,--....,'``. Let GNU/Linux work for you while you take a nap.
/, _.. \ _\ (`._ ,. R. Pfeiffer <lynx at luchs.at> + http://web.luchs.at/
`._.-(,_..'--(,_..'`-.;.' - System administration + Consulting + Teaching -
[-- Attachment #2: Type: application/pgp-signature, Size: 189 bytes --]
next prev parent reply other threads:[~2005-12-22 0:29 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-12-21 18:36 ICMP types to allow Derick Anderson
2005-12-21 18:48 ` John A. Sullivan III
2005-12-22 0:29 ` René Pfeiffer [this message]
2005-12-22 2:08 ` Chris Brenton
2005-12-22 11:03 ` René Pfeiffer
2005-12-22 8:50 ` lst_hoe01
-- strict thread matches above, loose matches on Subject: below --
2005-12-21 19:12 Derick Anderson
2005-12-21 16:31 Peter E. Fry
2005-12-21 13:45 Derick Anderson
2005-12-21 14:16 ` lst_hoe01
2005-12-21 16:27 ` Georgi Alexandrov
2005-12-21 19:22 ` Cedric Blancher
2005-12-21 22:01 ` Chris Brenton
2005-12-22 0:32 ` René Pfeiffer
2006-01-03 7:33 ` Jan Engelhardt
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20051222002905.GI25728@nightfall.luchs.at \
--to=lynx@luchs.at \
--cc=netfilter@lists.netfilter.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.