migration to iptables

migration to iptables

[Payal]

Hi all,
I used to use ipchains like 
ipchains -A forward -j MASQ 
to share internet connection. Now on Linux kernel 2.4.18 on Mdk 8.2 I want to 
try iptables for a while.
I just substitued ipchains in the above command with iptables 
iptables -A forward -j MASQ
iptables v1.2.5: Couldn't load target `MASQ':/lib/iptables/libipt_MASQ.so: 
cannot open shared object file: No such file or directory

I heard MASQ cannot be used like this here. How do I use iptables for the 
same purpose as for ipchains.
Thanks a lot in advance and sorry for the non-techinicality of the mail :)
Thanks and bye.
-Payal

Re: migration to iptables

[Antony Stone]

On Monday 10 June 2002 3:18 pm, Payal wrote:

> Hi all,
> I used to use ipchains like
> ipchains -A forward -j MASQ
> to share internet connection. Now on Linux kernel 2.4.18 on Mdk 8.2 I want
> to try iptables for a while.
> I just substitued ipchains in the above command with iptables
> iptables -A forward -j MASQ
> iptables v1.2.5: Couldn't load target `MASQ':/lib/iptables/libipt_MASQ.so:
> cannot open shared object file: No such file or directory

You need the appropriate FORWARD rules to allow the traffic through the box 
in the first place, but this is how you masquerade the source address behind 
your Internet link address:

iptables -A POSTROUTING -o $EXT_IF -j MASQUERADE

You might want to read:

http://www.netfilter.org/documentation/HOWTO/packet-filtering-HOWTO.html

http://www.netfilter.org/documentation/HOWTO/NAT-HOWTO.html

 

Antony.

Re: migration to iptables

[Payal]

Hi,
Thanks for the mails.

iptables -A POSTROUTING -o $EXT_IF -j MASQUERADE
Warning: wierd character in interface `-j' (No aliases, :, ! or *).
Bad argument `MASQUERADE'
Try `iptables -h' or 'iptables --help' for more information.

and this gave,
iptables -A forward -j MASQUERADE
iptables: No chain/target/match by that name

My aim is very simple, I just wanted the equivalent command for 
ipchains -A forward -j MASQ 
in iptables.
Thanks a lot in advance and eagerly waiting for the help.
-Payal
On Monday 10 June 2002 08:01 pm, you wrote:
> On Monday 10 June 2002 3:18 pm, Payal wrote:
> > Hi all,
> > I used to use ipchains like
> > ipchains -A forward -j MASQ
> > to share internet connection. Now on Linux kernel 2.4.18 on Mdk 8.2 I
> > want to try iptables for a while.
> > I just substitued ipchains in the above command with iptables
> > iptables -A forward -j MASQ
> > iptables v1.2.5: Couldn't load target
> > `MASQ':/lib/iptables/libipt_MASQ.so: cannot open shared object file: No
> > such file or directory
>
> You need the appropriate FORWARD rules to allow the traffic through the box
> in the first place, but this is how you masquerade the source address
> behind your Internet link address:
>
> iptables -A POSTROUTING -o $EXT_IF -j MASQUERADE
>
> You might want to read:
>
> http://www.netfilter.org/documentation/HOWTO/packet-filtering-HOWTO.html
>
> http://www.netfilter.org/documentation/HOWTO/NAT-HOWTO.html
>
>
>
> Antony.

Re: migration to iptables

[Axel Heinrici]

Hi

On Tuesday 11 June 2002 04:26, Payal wrote:
> Hi,
> Thanks for the mails.
>
> iptables -A POSTROUTING -o $EXT_IF -j MASQUERADE
> Warning: wierd character in interface `-j' (No aliases, :, ! or

Is it possible that EXT_IF is not set? This really looks like 
EXT_IF="". Try expicitly iptables -A POSTROUTING -o ppp0 -j 
MASQUERADE (or eth1 or whatever).
But I think it should be iptables -t nat -A POSTROUTING -o ..... -j 
MASQUERADE.

From info iptables:
  MASQUERADE
       This  target  is  only  valid  in  the  nat  table, in the
       POSTROUTING chain.


> *). Bad argument `MASQUERADE'
> Try `iptables -h' or 'iptables --help' for more information.

Same problem. May you should have a look at man iptables.

> and this gave,
> iptables -A forward -j MASQUERADE
> iptables: No chain/target/match by that name

Correct. MASQUERADE is not valid there.

> My aim is very simple, I just wanted the equivalent command for
> ipchains -A forward -j MASQ
> in iptables.
> Thanks a lot in advance and eagerly waiting for the help.
> -Payal


greetings 
	Axel