Duplicate IPFW rules

Oliver Fromme olli at lurza.secnetix.de
Fri Dec 22 00:16:21 PST 2006

Václav Haisman wrote:
 > I have just noticed that ipfw list shows one rule twice. It could be that I
 > have run a script that adds it twice:

That's expected behaviour.  Rule numbers are not unique.
Think of the rule number as a tag attached to the rule.
It's perfectly legal that two rules can have the same
tag (number).

 > Shouldn't IPFW check before adding the same rule number again?

No.  However, it could be argued that ipfw(8) could check
if an existing rule number is added with the same rule
body.  In that case it would be redundant and have no
effect at all.  (It wouldn't really be an error either,
so ipfw(8) could simply exit successfully without actually
adding the rule.)  If someone submits a patch for that,
I think it would be comitted.

Best regards

Oliver Fromme,  secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing
Dienstleistungen mit Schwerpunkt FreeBSD: http://www.secnetix.de/bsd
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