[c-nsp] eigrp question

Kern, Tom tkern at CHARMER.COM
Wed Jan 5 15:57:01 EST 2005


so if i open ipsec in my firewall, will that allow a gre tunnel from my internet router to my internal router to pass eigrp info?
thanks
-----Original Message-----
From: Serguei Bezverkhi [mailto:sbezverkhi at hotmail.com]
Sent: Wednesday, January 05, 2005 2:19 PM
To: Kern, Tom
Subject: RE: [c-nsp] eigrp question


To be able to deal with IPSec you will need to enable 

UDP port 500 - isakmp negotiation
ESP protocol type 50 

you do not really need it but FYI:

PPTP uses TCP port 1723
GRE protocol type 47

Unfortunately I do not know sonicwall, I work only with Cisco. Using PIX it
is very easy to accomplish.



Serguei

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Kern, Tom
Sent: Wednesday, January 05, 2005 1:37 PM
To: Cisco List 2 (E-mail)
Subject: RE: [c-nsp] eigrp question

the sonicwall has a built in ipsec(esp) rule however it seems to use ip
ports 0 and 50. it also has a ike rule and pptp. the pptp rule uses ports
1723 and ip port 6? I thought pptp IS gre?
shouldn't it use ip port 47?
thanks

-----Original Message-----
From: Serguei Bezverkhi [mailto:sbezverkhi at hotmail.com]
Sent: Wednesday, January 05, 2005 1:16 PM
To: Kern, Tom
Subject: RE: [c-nsp] eigrp question


You can also try to encrypt GRE tunnel using IPSec tunnel mode, so your
firewall will se only IPSec traffic. Hopefully your firewall will allow
IPSec pass through.

Serguei

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Kern, Tom
Sent: Wednesday, January 05, 2005 1:01 PM
To: Cisco List 2 (E-mail)
Subject: RE: [c-nsp] eigrp question

there is a router outside the firewall. its the stub router and only has
static routes.
i looked into SAA probes but my ios(12.2(6)) doesn't support it and the one
that does is too big for my flash and of course the powers that be don't
want to shell out any $$$ for a new flash card.

finally, i think i'm screwed because the sonicwall pro 100 in the remote
site doesn't have any pre built services for gre and doesn't have an option
to create a rule based on IP ports only tcp/udp.
sigh....

-----Original Message-----
From: barney gumbo [mailto:barney.gumbo at gmail.com]
Sent: Wednesday, January 05, 2005 12:53 PM
To: Kern, Tom
Subject: Re: [c-nsp] eigrp question


Is there a router beyond (outside) the firewall?  If so, GRE over
EIGRP will get the EIGRP packets through the firewall.  In other
words, build a GRE tunnel through the firewall and add the GRE network
(on both routers) into EIGRP.  Be careful not to redistribute the
external routing protocol (if there is one) into EIGRP and vice-versa.

BGP is actually quite simple on a basic level.  It get's tricky when
you need to exchange routes between BGP and an IGP, in this case
EIGRP.

However, it sounds like you don't have a router on the outside of the
firewall.  In this case you can set up policy-routing which will ping
a network, if the ping fails, the policy-routing will kick in and
change the route you need changed.

Check these links-

http://www.cisco.com/en/US/about/ac123/ac114/ac173/Q2-04/department_techtips
html

http://www.cisco.com/warp/public/784/packet/apr04/pdfs/dept_tt_scenarios.pdf

I use these features in my network.  Specifically I ping a destination
host that we're not exchanging routes with.  When that ping test
fails, policy-routing kicks in and the backup route is injected.  Once
the pings start working again, the original route is re-injected. 
Works quite well.

--Barn

On Wed, 5 Jan 2005 12:29:58 -0500, Kern, Tom <tkern at charmer.com> wrote:
> I'm trying to set up an internet redudancy plan. i have 3 sites all
connected via T1's. each site has its own internet connection(frame relay)
and i'd like to set it up so if one site's firewall(sonicwall and
watchguard) go down or the internet link goes down, internet traffic will
automagically be rerouted via one of the other site's internet connection.
> i'm avoiding bgp because i have no experince with it.
> all my routers run eigrp. i thought using "ip default-network" would work.
but if eigrp neighbors need to be on the same subnet, this won't help me.
also eigrp would only work if the whole router went down(rare). i want the
routes to change if the serial link is down.
> 
> does anyone know of a way to make this work? is it possible?
> thanks
> 
> -----Original Message-----
> From: Michel Py [mailto:michel at arneill-py.sacramento.ca.us]
> Sent: Wednesday, January 05, 2005 12:20 PM
> To: Kern, Tom
> Subject: RE: [c-nsp] eigrp question
> 
> > would an eigrp neighbor relationship be formed between
> > 2 routers if they are on seperate subnets?
> 
> No. (I would be very interested in this if it could work). So far the
> only thing I got to route across a firewall is either a tunnel (which
> defeats having a firewall) or BGP.
> 
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