raw packet capture based on offset

raw packet capture based on offset

[colorchip]

Hi,

I want to capture raw packets based on the ethernet source (mac) and a 16 bit identifier following the ethtype. I am unable to find a generic filter which gives me a freedom to filter the packet based on any bit length and offset from the beginning of the packet. Can anyone help?

-nks

Re: raw packet capture based on offset

[Alexey Toptygin]

On Thu, 22 Sep 2005 colorchip@sify.com wrote:

> I want to capture raw packets based on the ethernet source (mac) and a 
> 16 bit identifier following the ethtype. I am unable to find a generic 
> filter which gives me a freedom to filter the packet based on any bit 
> length and offset from the beginning of the packet. Can anyone help?

I think you want the u32 match from POM-ng.

 			Alexey

PPTP/IPSec multiple clients behind iptables NAT

[Salim]

I am using iptables 1.3.3

I had some problems with multiple clients behind NAT(a simple MASQUERADE
rule is set) connecting to the same VPN server. ONly one client can connect
at a time.
I have enables the CONFIG_IP_NF_PPTP and CONFIG_IP_NF_CT_PROTO_GRE options
in kernel.

I have read a few posts about this issue in the list from as early as in
2003. But could not find a conclusion.

Could you guys please clarify? Is this scenario supported by iptables? If
not, is there a way to get around this issue?

thanks
Salim

RE: PPTP/IPSec multiple clients behind iptables NAT

[Gary W. Smith]

PPTP requires a patching of the kernel and a recompile of the kernel and
iptables (against the new kernel headers) to make this work.  It also
matters which kernel version you are using.  There have been
miscellaneous problems with different kernels report.  I believe many
have been fixed though.

Gary Smith

> -----Original Message-----
> From: netfilter-bounces@lists.netfilter.org [mailto:netfilter-
> bounces@lists.netfilter.org] On Behalf Of Salim
> Sent: Thursday, September 22, 2005 6:58 PM
> To: netfilter@lists.netfilter.org
> Subject: PPTP/IPSec multiple clients behind iptables NAT
> 
> I am using iptables 1.3.3
> 
> I had some problems with multiple clients behind NAT(a simple
MASQUERADE
> rule is set) connecting to the same VPN server. ONly one client can
> connect
> at a time.
> I have enables the CONFIG_IP_NF_PPTP and CONFIG_IP_NF_CT_PROTO_GRE
options
> in kernel.
> 
> I have read a few posts about this issue in the list from as early as
in
> 2003. But could not find a conclusion.
> 
> Could you guys please clarify? Is this scenario supported by iptables?
If
> not, is there a way to get around this issue?
> 
> thanks
> Salim
> 

Re: PPTP/IPSec multiple clients behind iptables NAT

[Salim]

Thanks Gary.

My kernel is Red Hat 2.4.25.
Could you please give more details about the patch?

----- Original Message ----- 
From: "Gary W. Smith" <gary@primeexalia.com>
To: "Salim" <salim.si@askey.com.tw>; <netfilter@lists.netfilter.org>
Sent: Friday, September 23, 2005 10:03 AM
Subject: RE: PPTP/IPSec multiple clients behind iptables NAT


PPTP requires a patching of the kernel and a recompile of the kernel and
iptables (against the new kernel headers) to make this work.  It also
matters which kernel version you are using.  There have been
miscellaneous problems with different kernels report.  I believe many
have been fixed though.

Gary Smith

> -----Original Message-----
> From: netfilter-bounces@lists.netfilter.org [mailto:netfilter-
> bounces@lists.netfilter.org] On Behalf Of Salim
> Sent: Thursday, September 22, 2005 6:58 PM
> To: netfilter@lists.netfilter.org
> Subject: PPTP/IPSec multiple clients behind iptables NAT
> 
> I am using iptables 1.3.3
> 
> I had some problems with multiple clients behind NAT(a simple
MASQUERADE
> rule is set) connecting to the same VPN server. ONly one client can
> connect
> at a time.
> I have enables the CONFIG_IP_NF_PPTP and CONFIG_IP_NF_CT_PROTO_GRE
options
> in kernel.
> 
> I have read a few posts about this issue in the list from as early as
in
> 2003. But could not find a conclusion.
> 
> Could you guys please clarify? Is this scenario supported by iptables?
If
> not, is there a way to get around this issue?
> 
> thanks
> Salim
> 

RE: PPTP/IPSec multiple clients behind iptables NAT

[Gary W. Smith]

You need to down patch-o-matic but the problem is that RH 2.4 kernel is
a hybrid kernel (uses much of 2.6 in it).  I am running the patch on
RHES 4.

Gary

> -----Original Message-----
> From: Salim [mailto:salim.si@askey.com.tw]
> Sent: Thursday, September 22, 2005 7:24 PM
> To: Gary W. Smith; netfilter@lists.netfilter.org
> Subject: Re: PPTP/IPSec multiple clients behind iptables NAT
> 
> Thanks Gary.
> 
> My kernel is Red Hat 2.4.25.
> Could you please give more details about the patch?
> 
> ----- Original Message -----
> From: "Gary W. Smith" <gary@primeexalia.com>
> To: "Salim" <salim.si@askey.com.tw>; <netfilter@lists.netfilter.org>
> Sent: Friday, September 23, 2005 10:03 AM
> Subject: RE: PPTP/IPSec multiple clients behind iptables NAT
> 
> 
> PPTP requires a patching of the kernel and a recompile of the kernel
and
> iptables (against the new kernel headers) to make this work.  It also
> matters which kernel version you are using.  There have been
> miscellaneous problems with different kernels report.  I believe many
> have been fixed though.
> 
> Gary Smith
> 
> > -----Original Message-----
> > From: netfilter-bounces@lists.netfilter.org [mailto:netfilter-
> > bounces@lists.netfilter.org] On Behalf Of Salim
> > Sent: Thursday, September 22, 2005 6:58 PM
> > To: netfilter@lists.netfilter.org
> > Subject: PPTP/IPSec multiple clients behind iptables NAT
> >
> > I am using iptables 1.3.3
> >
> > I had some problems with multiple clients behind NAT(a simple
> MASQUERADE
> > rule is set) connecting to the same VPN server. ONly one client can
> > connect
> > at a time.
> > I have enables the CONFIG_IP_NF_PPTP and CONFIG_IP_NF_CT_PROTO_GRE
> options
> > in kernel.
> >
> > I have read a few posts about this issue in the list from as early
as
> in
> > 2003. But could not find a conclusion.
> >
> > Could you guys please clarify? Is this scenario supported by
iptables?
> If
> > not, is there a way to get around this issue?
> >
> > thanks
> > Salim
> >

Re: PPTP/IPSec multiple clients behind iptables NAT

[Salim]

PPTP multiple client passthrough is working now, with the patch. Thatz
great.
IPSec do not have any patch for NAT, it seems. Any info on how to go about
that?

----- Original Message -----
From: "Gary W. Smith" <gary@primeexalia.com>
To: "Salim" <salim.si@askey.com.tw>; <netfilter@lists.netfilter.org>
Sent: Friday, September 23, 2005 10:23 AM
Subject: RE: PPTP/IPSec multiple clients behind iptables NAT


You need to down patch-o-matic but the problem is that RH 2.4 kernel is
a hybrid kernel (uses much of 2.6 in it).  I am running the patch on
RHES 4.

Gary

> -----Original Message-----
> From: Salim [mailto:salim.si@askey.com.tw]
> Sent: Thursday, September 22, 2005 7:24 PM
> To: Gary W. Smith; netfilter@lists.netfilter.org
> Subject: Re: PPTP/IPSec multiple clients behind iptables NAT
>
> Thanks Gary.
>
> My kernel is Red Hat 2.4.25.
> Could you please give more details about the patch?
>
> ----- Original Message -----
> From: "Gary W. Smith" <gary@primeexalia.com>
> To: "Salim" <salim.si@askey.com.tw>; <netfilter@lists.netfilter.org>
> Sent: Friday, September 23, 2005 10:03 AM
> Subject: RE: PPTP/IPSec multiple clients behind iptables NAT
>
>
> PPTP requires a patching of the kernel and a recompile of the kernel
and
> iptables (against the new kernel headers) to make this work.  It also
> matters which kernel version you are using.  There have been
> miscellaneous problems with different kernels report.  I believe many
> have been fixed though.
>
> Gary Smith
>
> > -----Original Message-----
> > From: netfilter-bounces@lists.netfilter.org [mailto:netfilter-
> > bounces@lists.netfilter.org] On Behalf Of Salim
> > Sent: Thursday, September 22, 2005 6:58 PM
> > To: netfilter@lists.netfilter.org
> > Subject: PPTP/IPSec multiple clients behind iptables NAT
> >
> > I am using iptables 1.3.3
> >
> > I had some problems with multiple clients behind NAT(a simple
> MASQUERADE
> > rule is set) connecting to the same VPN server. ONly one client can
> > connect
> > at a time.
> > I have enables the CONFIG_IP_NF_PPTP and CONFIG_IP_NF_CT_PROTO_GRE
> options
> > in kernel.
> >
> > I have read a few posts about this issue in the list from as early
as
> in
> > 2003. But could not find a conclusion.
> >
> > Could you guys please clarify? Is this scenario supported by
iptables?
> If
> > not, is there a way to get around this issue?
> >
> > thanks
> > Salim
> >