Re: [LARTC] Gre Tunneling Problem

["Greg Scott" <GregScott@InfraSupportEtc.com>]

I tried an experiment a couple months ago, lifted the commands right out of
the HOWTO and
chzanged the IP addresses and it all worked just fine.  For a bunch of
unrelated reasons, I
didn't get to put mine into long term production, but I am confident that
the HOWTO works.

Here's what's been bugging me - I didn't see anything about shared secrets
or passwords or anything like that.  How does the security work?  What's to
stop any Joe Blow from
impersonating one of the IP Addresses in a Linux PPTP-GRE tunnel?  Is there
any encryption?

- Greg


----- Original Message -----
From: "glynn" <glynn@itextron.com>
To: "Joe Patterson" <jpatterson@asgardgroup.com>; "Christoph Simon"
<ciccio@kiosknet.com.br>
Cc: <lartc@mailman.ds9a.nl>
Sent: Sunday, January 06, 2002 10:04 PM
Subject: Re: [LARTC] Gre Tunneling Problem


> Hi Joe, I tried it and it wont work, same result, I could ping both but it
> wont result the internal ip addresses, it seems that it only resolves the
in
> the interfaces but it wont allow to forward. can you figure out again pls.
> Thanks.
>
> Glynn
>
>
> ----- Original Message -----
> From: "Joe Patterson" <jpatterson@asgardgroup.com>
> To: "glynn" <glynn@itextron.com>; "Christoph Simon"
<ciccio@kiosknet.com.br>
> Cc: <lartc@mailman.ds9a.nl>
> Sent: Tuesday, January 08, 2002 9:01 AM
> Subject: RE: [LARTC] Gre Tunneling Problem
>
>
> > I would suggest using a different network for the gre tunnel, like:
> >
> > Linux A
> > ip tunnel add netb mode gre remote 205.198.x.1 local 203.189.x.1 ttl 255
> > ip link set netb up
> > ip addr add 192.168.3.1/30 dev netb
> > ip route add 192.168.2.0/24 dev netb via 192.168.3.2
> >
> > Linux B
> > ip tunnel add neta mode gre remote 203.189.x.1 local 205.198.x.1 ttl 255
> > ip link set neta up
> > ip addr add 192.168.3.2/30 dev neta
> > ip route add 192.168.1.0/24 dev neta via 192.168.3.1
> >
> > Otherwise, it's just wierd.  Not that that's bad, it just sometimes
> doesn't
> > work...
> >
> > -Joe
> >
> >
> > > -----Original Message-----
> > > From: lartc-admin@mailman.ds9a.nl
[mailto:lartc-admin@mailman.ds9a.nl]On
> > > Behalf Of glynn
> > > Sent: Sunday, January 06, 2002 7:59 PM
> > > To: Christoph Simon
> > > Cc: lartc@mailman.ds9a.nl
> > > Subject: Re: [LARTC] Gre Tunneling Problem
> > >
> > >
> > > Hello Christoph, actually I havent done with netfilter rules and
> > > i dont have
> > > any restrictions applied for the linux, its a normal configuration, I
> also
> > > enable the forwarding under the /proc/sys/net/ipv4/ip_forward
> > > with the value
> > > of 1. can you figure out whats the problem? thanks
> > >
> > > Glynn
> > >
> > > ----- Original Message -----
> > > From: "Christoph Simon" <ciccio@kiosknet.com.br>
> > > To: "glynn" <glynn@itextron.com>
> > > Cc: <lartc@mailman.ds9a.nl>
> > > Sent: Monday, January 07, 2002 7:41 PM
> > > Subject: Re: [LARTC] Gre Tunneling Problem
> > >
> > >
> > > > On Sun, 6 Jan 2002 17:39:46 +0800
> > > > "glynn" <glynn@itextron.com> wrote:
> > > >
> > > > > Hello everyone, I have a problem regarding gre tunneling, I have
two
> > > > > linux box both of them has a private network and the linux A is
> > > > > connected to the internet via wireless radio and the other linux B
> is
> > > > > connected to the internet via lease line. Here is the setup of my
> two
> > > > > linux box
> > > > >
> > > > > Linux A
> > > > > eth0 = 203.189.x.1 (internet)
> > > > > eth1 = 192.168.1.1 (going to hub private network)
> > > > >
> > > > > Linux B
> > > > > eth0 = 205.198.x.1 (internet)
> > > > > eth1 = 192.168.2.1 (going to hub private network)
> > > > >
> > > > > here is my configuration in Linux A and B. I also load the modules
> > > > > needed (insmod ip_gre)
> > > > >
> > > > > Linux A
> > > > > ip tunnel add netb mode gre remote 205.198.x.1 local
> > > 203.189.x.1 ttl 255
> > > > > ip link set netb up
> > > > > ip addr add 192.168.1.1 dev netb
> > > > > ip route add 192.168.2.0/24 dev netb
> > > > >
> > > > > Linux B
> > > > > ip tunnel add neta mode gre remote 203.189.x.1 local
> > > 205.198.x.1 ttl 255
> > > > > ip link set neta up
> > > > > ip addr add 192.168.2.1 dev neta
> > > > > ip route add 192.168.1.0/24 dev neta
> > > > >
> > > > > I could ping both sides the eth0 and also the eth1 with is for the
> > > > > private network, here is my problem i couldnt ping the other
> > > private ip
> > > > > addresses which my eth1 is connected to the hub, anyone can help
me,
> > > > > whats my error. pls reply asap. thanks
> > > >
> > > > Do you have any netfilter rules not letting pass proto 47? You'll
also
> > > > have to allow forwarding.
> > > >
> > > > --
> > > > Christoph Simon
> > > > ciccio@kiosknet.com.br
> > > > ---
> > > > ^X^C
> > > > q
> > > > quit
> > > > :q
> > > > ^C
> > > > end
> > > > x
> > > > exit
> > > > ZZ
> > > > ^D
> > > > ?
> > > > help
> > > > .
> > > >
> > >
> > >
> > > _______________________________________________
> > > LARTC mailing list / LARTC@mailman.ds9a.nl
> > > http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO:
> http://ds9a.nl/lartc/
> > >
> >
> >
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http://ds9a.nl/lartc/
> >
>
>
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