Re: 3 iptables accounting questions

[Etienne Ledoux <etienne@unix.za.org>]

**ninja-bow**

On Tuesday 06 July 2004 23:55, Alexander Samad wrote:
> On Tue, Jul 06, 2004 at 11:07:25AM +0200, Etienne Ledoux wrote:
> > super answer! tx!
> >
> > 1)
> > Should I change the 10.168.0.2/32 to 0.0.0.0/0 ? Would that catch
> > everything on eth0 ? My internal lan is 192.168.0.0/24. But mail is
> > delivered directly to the fw which wont pass to the internal network but
> > is also part of the internet traffic. So I guess I have to types of
> > internet traffic. 192.168.0.0/24 which is the internal network doing the
> > usual stuff on the internet like browsing etc. and mail which is going
> > to/from 10.168.0.2 which is the external ethernet of the firewall.
> >
> > 2) iptables-save -c ACCT
> > Unknown arguments found on commandline
> >
> > I guess I'm doing something stupid here. What would the right syntax be ?
> >
> > e.
> >
> > On Tuesday 06 July 2004 10:45, Antony Stone wrote:
> > > On Tuesday 06 July 2004 9:17 am, Etienne Ledoux wrote:
> > > > Greetings,
> > > >
> > > > 1) I have a firewall and would like to count all the traffic
> > > > entering/leaving the external interface (I want to count only
> > > > internet traffic, which is the traffic entering/leaving the external
> > > > if). Is this rule right ?
> > > >
> > > > iptables -N ACCT
> > > > iptables -I FORWARD -j ACCT
> > > > iptables -I INPUT -j ACCT
> > > > iptables -I OUTPUT -j ACCT
> > > > iptables -A ACCT -s 10.168.0.2/32 -d 0.0.0.0/0 -o eth0
> > > > iptables -A ACCT -s 0.0.0.0/0 -d 10.168.0.2/32 -i eth0
>
> why not something like
>
> iptables -t mangle -N ACCT
> iptables -t mangle -I PREROUTING 1 -i eth0 -j ACCT
> iptables -t mangle -I POSTROUTING 1 -o eth0 -j ACCT
>
> iptables -A ACCT -i eth0
> iptables -A ACCT -o eth0
>
>
> This should capture every thing entering and leave via eth0
>
> > > > 10.168.0.2 is my external interface ip and is also the ip which my
> > > > internal network is natted behind.
> > >
> > > You want to count traffic addressed *to this machine* from the
> > > Internet, and traffic addressed *from this machine* to the Internet,
> > > yes?   In that case these rules will work, but there is no point in
> > > jumping to the ACCT chain from the FORWARD chain.
> > >
> > > Remember that FORWARD is *only* for traffic going through the machine,
> > > and INPUT and OUTPUT are *only* for traffic to/from the machine (ie:
> > > *never* for traffic going through it).
> > >
> > > If you want to count traffic addressed *to any machine on your internal
> > > network* from the Internet, and traffic addressed *from any machine on
> > > your network* to the Internet, then you should use your subnet address
> > > in the -s and -d options, not the address of your firewall.
> > >
> > > At a guess this subnet is going to be 10.168.0.0/24, but I don't know
> > > what netmask you're using.
> > >
> > > > 2) I would like to save/restore only this accounting rule. I thought
> > > > 'iptables-save -c -t ACCT' would work but it doesn't.
> > >
> > > No, ACCT is not a table (like filter, nat and mangle are) - it is a
> > > chain (like FORWARD, INPUT and OUTPUT are).   Don't use -t
> > >
> > > > 3) How do I flush the accounting stats.
> > >
> > > iptables -Z ACCT, or iptables -L -Z ACCT -nvx if you want to see the
> > > counters immediately before zeroing them.
> > >
> > > Regards,
> > >
> > > Antony.