netfilter and kernel 2.5.* ipsec

netfilter and kernel 2.5.* ipsec

[Andreas Jellinghaus]

Hi,

using setkey I can create rules based on
 - src ip, dst ip, src port, dest port, proto

using netfilter I can create rules on (but not limited to)
 - src ip, dst ip, src port, dest port, proto, state,
   incoming interface, outgoing interface, ...

so netfilter is a lot better. but netfilter cannot set
requirements for ipsec?

Is there any guide how to combine these two?

I could allow more or less anything with iptables
(only filter bogus packets etc.), and restrict access
to certain ports in the SPD database.

But isn't there a nicer way to do that?
I have real trouble with the combination of
SPD and dynamic ip: 
  my machine has a dynamic ip, and of course I want
  restrict access to most ports, unless an ipsec
  connection is used. using spdadd I need to specify
  my IP as target, so that is quite ugly. e.g.

spdadd 0.0.0.0/0 192.168.0.10[25] -P in deny;

I would need to change that rule everytime my ip changes,
so I don't like doing that.

Also good security is always about shutting everything down
and then making small holes where necessary. I don't want
to have a big fat hole in my iptables config, but I don't see
how else I can allow access to certain ports, but restrict
the access to ipsec connections.

With kernel 2.4.* the ipsec0 interface was used in rules
to match whether a packet is coming in via ipsec or not.
Is there a similiar way to do the same thing?

Regards, 

Andreas