From: Michael Breen (mbreen@xxxxxxxxx)
Date: Mon Jun 03 2002 - 22:02:58 GMT-3
IPSec protected GRE tunnels are used when doing site to site VPNs across the
Internet. For instance, if you were running a site to site VPN across the
Internet, a GRE tunnel would pass multicast traffic (routing updates ).
However, It's probably not a good idea to allow people on the Internet to
SEE your routing updates. This is where IPSec comes in. By encrypting the
GRE tunnel with IPSec, you now have a way to pass routing updates without
anyone being able to see them because they are encrypted.
--MB
-----Original Message-----
From: Tom Young [mailto:gitsyoung@yahoo.co.jp]
Sent: Monday, June 03, 2002 6:13 PM
To: mbreen@cisco.com
Cc: ccielab@groupstudy.com
Subject: RE: IPSec&GRE
Michael,
It is great ! I knew it, thanks alot.
You said IPSec&GRE protects Multicast? I don't know what
is it means. If the internet has the protocol of OSPF and
BGP,etc. Could I make a IPSec%GRE through it? And some
thing I have to pay attention?
Thanks again
Young
--- Michael Breen <mbreen@cisco.com> $B$+$i$N%a%C%;!<%8!'(B
> IPSec is a encrypted tunnel that protects packets.
> GRE is an unencrypted tunnel that passes Multicast
> traffic.
> An IPSec protected GRE tunnel is an encrypted tunnel
> that protects Multicast
> packets.
>
> --MB
>
> -----Original Message-----
> From: nobody@groupstudy.com
> [mailto:nobody@groupstudy.com]On Behalf Of Tom
> Young
> Sent: Monday, June 03, 2002 9:24 AM
> To: elping
> Cc: ccielab@groupstudy.com
> Subject: Re: IPSec&GRE
>
>
> Thanks for your reply, would you teach me further,
> when
> could I use IPSec, when could I use GRE and when
> could I
> use the combine of IPSec&GRE?
>
> Thanks
>
> Young
>
>
>
> --- elping <elping@acedsl.com> $B$+$i$N%a%C%;!<%8!'(B
> > you will notice it is a tunnel if you do a trace
> > across ipsec
> > it will be one hop
> >
> >
>
-----r1(ipsec)-------r2-------r3--------r4-------(ipsec)r5
> > if you trace from r1 to r5 it will show one hop
> >
> > Tom Young wrote:
> >
> > > A question about the IPSec and GRE, I want to
> know
> > when I
> > > use the GRE combine with IPSec, When I only use
> > IPSec is
> > > ok. Does IPSec has the function of making a
> > tunnel?
> > >
> > > Thanks
> > >
> > > Young
> > >
> > >
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