From: Mark Vevers <mark@vevers.net>
To: Jet <yenjet.chan@eglobal.com.my>,
"netfilter@lists" <netfilter@lists.netfilter.org>
Subject: Re: TCP flags
Date: Wed, 6 Nov 2002 12:30:03 +0000 [thread overview]
Message-ID: <200211061230.05922.mark@vevers.net> (raw)
In-Reply-To: <005401c2856b$099aa5c0$0bc8c80a@dolphin>
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
On Wednesday 06 Nov 2002 08:03, Jet wrote:
> Can anyone just explain what is this means?
>
> iptables -A INPUT -p tcp --tcp-flags SYN,FIN SYN,FIN -j DROP
>
> I don't quite understand why there is a white space between SYN,FIN and
> SYN,FIN.
Yup - it means inspect the SYN and FIN flags and if they are both set drop the
packet. i.e. just look at the SYN and FIN flags - don't worry about any
others when doing the test to see if the rule matches.
The first pair are the flags to inspect, the second pair (after the space) are
the state of the flags to test.
Mark
- --
Mark Vevers. mark@ifl.net / mark@vevers.net
Principal Internet Engineer, Internet for Learning,
Research Machines Plc. (AS5503)
- --
GPG Key: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0xB08F3CA3
Fingerprint: 85BA 30C4 9EC8 1792 4C8C C31E 58B5 3D1C B08F 3CA3
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.0.6 (GNU/Linux)
Comment: For info see http://www.gnupg.org
iD8DBQE9yQtLWLU9HLCPPKMRAp8iAKCKQP6xrcuvP6UfglVcf0dl2owthwCfcKpU
7tz1W4J2UBkGvYH/dMTsZWU=
=FNMb
-----END PGP SIGNATURE-----
next prev parent reply other threads:[~2002-11-06 12:30 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-11-06 8:03 TCP flags Jet
2002-11-06 12:12 ` Maciej Soltysiak
2002-11-06 12:30 ` Mark Vevers [this message]
-- strict thread matches above, loose matches on Subject: below --
2003-12-23 15:05 TCP Flags zippo
2003-12-23 15:14 ` Antony Stone
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=200211061230.05922.mark@vevers.net \
--to=mark@vevers.net \
--cc=netfilter@lists.netfilter.org \
--cc=yenjet.chan@eglobal.com.my \
/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.