Re: [gentoo-user] IPTABLES syntax change?

[Pandu Poluan <pandu@poluan.info>]

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On Jan 3, 2013 4:40 AM, "Michael Orlitzky" <michael@orlitzky.com> wrote:
>
> On 12/30/12 22:21, Walter Dnes wrote:
> >   OK, here is version 2.  I had "an excellent adventure" along the way.
> >
>
> I'm doing the upgrade on our servers right now, and there's another
> possible gotcha: the newer iptables (requiring conntrack) requires
> NETFILTER_XT_MATCH_CONNTRACK support in the kernel. This is in contrast
> to the state matches which used NETFILTER_XT_MATCH_STATE.
>
> To minimize downtime during the switch, I'm doing,
>
>   1. Rebuild the kernel, enable conntrack and disable state.
>
>   2. Fix my iptables-config script to use the conntrack stuff
>
>   3. Create a dummy set of rules that allows me to SSH in (without
>      state matching)
>
>   4. Run and save those rules
>
>   5. Reboot to new kernel
>
>   6. SSH in and run iptables-config
>
>   7. Save the rules
>
>
> > [0:0] -A INPUT -s 192.168.123.248/29 -i eth0 -j ACCEPT
> > [0:0] -A INPUT -s 169.254.0.0/16 -i eth0 -j ACCEPT
> > [0:0] -A INPUT -i lo -j ACCEPT
> > [0:0] -A INPUT -m conntrack --ctstate INVALID,NEW -j UNSOLICITED
> > [0:0] -A INPUT -p tcp -m multiport --dports 0:1023,6000:6063 -j
BAD_DPORT
> > [0:0] -A INPUT -p udp -m multiport --dports 0:1023,6000:6063 -j
BAD_DPORT
> > [0:0] -A INPUT -s 69.63.176.0/20 -j FECESBOOK
> > [0:0] -A INPUT -s 69.220.144.0/20 -j FECESBOOK
> > [0:0] -A INPUT -s 69.63.176.0/20 -j FECESBOOK
> > [0:0] -A INPUT -s 69.171.224.0/19 -j FECESBOOK
> > [0:0] -A INPUT -s 200.58.112.0/20 -j FECESBOOK
> > [0:0] -A INPUT -s 213.155.64.0/19 -j FECESBOOK
> > [0:0] -A INPUT -s 10.0.0.0/8 -j PRIVATE_LOG
> > [0:0] -A INPUT -s 127.0.0.0/8 -j PRIVATE_LOG
> > [0:0] -A INPUT -s 172.16.0.0/12 -j PRIVATE_LOG
> > [0:0] -A INPUT -s 192.168.0.0/16 -j PRIVATE_LOG
> > [0:0] -A INPUT -p icmp -j ICMP_IN
> > [0:0] -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
>
> These rules will be evaluated in order. I have no evidence for this, but
> I suspect you're better off accepting the ESTABLISHED,RELATED stuff
> earlier in the chain so you don't slow down the packets that you want.
>

True. But you will want to filter out 'suspicious' packets beforehand.

In my previous employment, I had a Gentoo-based firewall with more than 100
lines of rules. Plus I also employ 'ipset' to allow on-the-fly manipulation
of blocking/routing.

If you want to see the whole nine yards, I can try asking my replacement to
send me the whole deal.

Rgds,
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