Re: iptables - resource temporary unavailable

["robee" <mlody@elpec.com>]

----- Original Message ----- 
From: "Philip Craig" <philipc@snapgear.com>
To: "robee" <mlody@elpec.com>
Cc: <netfilter@lists.netfilter.org>
Sent: Thursday, June 08, 2006 9:39 AM
Subject: Re: iptables - resource temporary unavailable

> On 06/08/2006 04:18 PM, robee wrote:
>>> (Not that I know the solution, but..) Iptables is a userspace utility to
>>> setup rules. Once the rule is setup, iptables itself terminates and
>>> Netfilter (kernelspace) will use the rule.
>>> Although you could add the same rule multiple times (which is a bit
>>> useless..), AFAICS there's no way to have Netfilter "running" multiple
>>> times.
>>> But you do have a point: is the OP flushing all rules/deleting all
>>> user-chains when he is restarting the firewall script ?
>>> Gr,
>>> Rob
>> yes, the first rules are:
>> iptables -F
>> iptables -F -t nat
>> iptables -F -t mangle
>> but, the same time firewall is restarting there also pppoe server
>> working.  if-up.local file contain iptables rules also and it might be
>> that iptables  lines from firewall and from if-up.local script are
>> running the same time.
> Yes, that is what I meant... the iptables userspace program has to use
> a kernel interface to install the rules.  If another instance of the
> iptables userspace program is currently installing some rules already,
> then the kernel interface will be in use, and you'll get this error.
> Or something like that; I haven't looked at the source code in detail.
> I've never seen this error myself, but I use locking around all calls
> to iptables.  You should be doing this anyway if you are using iptables
> rather than iptables-restore, since your script's operation isn't
> atomic if it calls iptables multiple times.

Could you tell me how do you lock around calls to iptables?


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