ipfw question

Giorgos Keramidas keramida at freebsd.org
Mon Sep 20 08:13:42 PDT 2004

On 2004-09-20 22:43, adrian kok <adriankok2000 at yahoo.com.hk> wrote:
> 1/ Recently, my mrtg graph showed many spikes
> "Incoming" in outer interface of the router.
> ls it possible to log them and check?

It is.  A better approach is to block everything that you don't really
need and then start logging legitimate connections only if the problems
with ``traffic spikes'' continue.

> If I log everthing, I am afraid to slow down the
> network. What is the best way to do it?

Don't do it.  It will truly slow down things a lot.

> 2/ I read some firewall docs. they said that it is
> good to allow 5% bandwidth for icmp only
> ls it true?

I don't know what docs you read about firewalls.  The Handbook has a
fairly good section on firewalls.  Have you read that?  If not, you
should definitely give it a look.

For an early chance to read what the ``Firewalls'' section will soon be
replaced with, you might also want to read this:


I'm working with a few other guys to get this into the Handbook as the
new ``Firewalls'' section before 5.3-RELEASE, but if it does help you
should definitely read it.  Joseph J. Barbish has written a couple of
excellent firewall tutorials and guides that I've read so far, and this
one is really worth a careful read.

Just note that the text at the above URL is probably going to change a
bit during the next couple of days, so be patient if you see changes
going in :-)

> how can I do it?

See above.


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