Solved

GRE tunnel with crypto statement matching source and destination

Posted on 2007-03-26
4
402 Views
Last Modified: 2008-02-01
Conceptually trying to understand something with IPSec.  Just want to know if what I'm thinking is correct...

I have two endpoints 1.1.1.1 and 1.1.1.1.2.  The local networks on those two networks are 192.168.1.1 and 192.168.2.1 respectively.  

I setup a GRE tunnel to match the two external IPs.  I setup a cryptomap over this GRE tunnel, but in my crytpo statements I only match the gre traffic.  

I route to each network via the GRE tunnel, but that GRE tunnel is encrypted?  Normally, I would match my local networks in my crypto statement so that they are encrypted (show crypto ipsec sa), but I saw a configuration like this the other day and it got me scratching my head.  If I only match on GRE traffic, I'm seting up an IPSEC Gre tunnel but is my local traffic passing over it still secure?  

 
0
Comment
Question by:neowolf219
  • 2
  • 2
4 Comments
 
LVL 32

Expert Comment

by:rsivanandan
ID: 18793684
You're probably looking at the typical ipsec tunnel where the tunnel is encrypted only between the end points and the local networks behind each endpoints are not even aware that their traffic is getting encrypted.

This is quite possible in site-to-site lan.

Cheers,
Rajesh
0
 
LVL 3

Author Comment

by:neowolf219
ID: 18794428
Hey Rajesh, that is correct.  My question was, those local networks are not matched in my access-list that defines interesting traffic for my crypto statement.  The only access-list for interesting traffic was as follows

access-list XXX permit gre host 1.1.1.1 host 1.1.1.2

So, the GRE traffic is what is being encrypted under IPSec, whereas my local networks are routing over the specific GRE tunnel.

Does that make sense?  Can I look at this as, well the GRE tunnel is IPSec encrypted, so therefore my local traffic going over GRE is also encrypted?

0
 
LVL 32

Accepted Solution

by:
rsivanandan earned 500 total points
ID: 18797409
Looks a little different to me, would it be possible for you to post the configuration ? (sanitized configuration-> take off the passwords part and remove the first octect of your public ip )

Cheers,
Rajesh
0
 
LVL 3

Author Comment

by:neowolf219
ID: 18803190
Below link is actually exactly what I'm looking at and makes sense.  Thanks for the responses though.  You get the points cause you were teh only one that bothered to even try to answer.  

http://www.cisco.com/en/US/tech/tk583/tk372/technologies_configuration_example09186a008009438e.shtml

0

Featured Post

PRTG Network Monitor: Intuitive Network Monitoring

Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
implementing stronger VPN connection protocols 7 34
iptables limit connection per ip correct way ? 2 199
How setup ip cams with cloud 7 145
SRX240 SYSLOG Setting 6 120
Do you have a windows based Checkpoint SmartCenter for centralized Checkpoint management?  Have you ever backed up the firewall policy residing on the SmartCenter?  If you have then you know the hassles of connecting to the server, doing an upgrade_…
How to set-up an On Demand, IPSec, Site to SIte, VPN from a Draytek Vigor Router to a Cyberoam UTM Appliance. A concise guide to the settings required on both devices
With Secure Portal Encryption, the recipient is sent a link to their email address directing them to the email laundry delivery page. From there, the recipient will be required to enter a user name and password to enter the page. Once the recipient …
In an interesting question (https://www.experts-exchange.com/questions/29008360/) here at Experts Exchange, a member asked how to split a single image into multiple images. The primary usage for this is to place many photographs on a flatbed scanner…

831 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question