Re: MASQ not resetting.

From: Rogier Wolff (R.E.Wolff@harddisk-recovery.nl)
Date: Sun Jul 23 2000 - 17:20:02 EST


Thorsten Kranzkowski wrote:
> On Sun, Jul 23, 2000 at 03:51:33PM +0200, Rogier Wolff wrote:
> >
> > It seems as if the masq table entry has an IP address entry. Shouldn't
> > this be a reference to "the IP addr of that interface"? Thus when the
> > interface goes down and comes back up, the new addr is used?
>
> According to the NAT HOWTO (see www.samba.org/netfilter) a _masqueraded_
> connection's table entry will be dropped when the interface goes down.
 
> I assume you use an ISDN dialup (you mention the IP-up script). The

No, I'm using regular PPP. Doesn't that have an IP-up script? Anyhow,
I'm using "sleep 60;<do stuff> " instead of the IP-up script. Call me
a fool.

> problem is (I think) that the interface (ippp0) is _NOT_ going
> down. Only the ISDN link is, but interface, routing (and NAT
> entries) are kept 'up' so dynamic dialling can work. Of course old
> NAT entries are useless with a new connection.

Problem COULD be that these are UDP "connections", which officially
aren't connections at all.

> Probably a solution is to insert 'ifconfig ippp0 down; ifconfig ippp0 up'
> along with a possible 'route -add ...' into your IP-down script.

If they really should be dropped on the interface going down, then
I've found a problem (i.e. docs do not conform with practise).

> > (it is wrong to take the masq entry down with the interface: Then
> > people with fixed-ip will see their masqed connections go down, over a
> > power-cycle of their modem)
>
> People with fixed ip-address should use SNAT not MASQUERADE. SNATed entries
> aren't dropped.

OK. So when my PPP interface goes down, my masq entries aren't dropped!

                                Roger.

-- 
** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2137555 **
*-- BitWizard writes Linux device drivers for any device you may have! --*
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