openstack team mailing list archive

[Mark McLoughlin <markmc@xxxxxxxxxx>]

On Mon, 2011-10-10 at 12:58 +0100, Mark McLoughlin wrote:
> On Mon, 2011-10-10 at 12:29 +0100, Kiall Mac Innes wrote:
> > Hi Mark,
> > 
> > That part I understand :) Consider these rules (nabbed from forum posting
> > here<http://www.zeroshell.net/eng/forum/viewtopic.php?p=655&sid=76f8a08777176b9f939642734f2b23d0#655>
> > ):
> > 
> > iptables -t nat -A prerouting_rule -d WAN_IP -p tcp --dport 80 -j DNAT --to
> > > 192.168.0.10
> > > iptables -A forwarding_rule -p tcp --dport 80 -d 192.168.0.10 -j ACCEPT
> > > iptables -t nat -A postrouting_rule -s 192.168.0.0/24 -p tcp --dport 80 -d
> > > 192.168.0.10 -j MASQUERADE
> > 
> > 
> > Some pretty "basic" iptables based router distro's like pfSense etc call
> > this hairpin NAT or NAT reflection..
> 
> Ah, I see - hairpin is basically adding a rule which snats (as well as
> the standard dnat) connections from the private network to the public IP
> 
> > And, I'm wondering if a similar technique is possible with the rules
> > OS generates?
> 
> It seems perfectly possible to me - you'd need to add something similar
> to that last rule in ensure_floating_forward() in linux_vnet.py
> 
> The only tricky bit is that you'll need to pass the fixed IP network's
> cidr down from init_host_floating_ips() - I'm guessing it's available by
> something like floating_ip['fixed_ip']['network']['cidr']
> 
> If you've any trouble getting it working, at least file a bug in
> launchpad - it sounds like a useful feature

Hah, I see you filed a similar bug against Euca some time ago :)

  https://bugs.launchpad.net/eucalyptus/+bug/676167

Cheers,
Mark.