We're Sorry, Full Content Access is for Members Only...

If you like to keep on reading, Become a Member Now! Here is Why:

  • Learn any CCNA, CCNP and CCIE R&S Topic. Explained As Simple As Possible.
  • Try for Just $1. The Best Dollar You've Ever Spent on Your Cisco Career!
  • Full Access to our 641 Lessons. More Lessons Added Every Week!
  • Content created by Rene Molenaar (CCIE #41726)


370 New Members signed up the last 30 days!


100% Satisfaction Guaranteed!
You may cancel your monthly membership at any time.
No Questions Asked!

Tags: , ,

Forum Replies

  1. Hi Rene! Your articles are awesome!!! You are doing a great job! Thank you. I have a question about this article. In this topology we have three routers with interfaces in one subnet, what is the point of having gre tunnel in this topology? We can run ospf (or other protocol) without gre tunnel.

  2. Hi Joey,

    It’s one or the other, the keyring is a replacement for the crypto isakmp key command where you can store all keys for different peers.


  3. Hi Rene,

    I am confused about the two term GRE over IPSec or IPSec over GRE . Both are same ??? if not then what is the difference between two. Many thanks


  4. Hello again Mohammad.

    Usually, when one uses the term GRE over IPSec, we are usually talking about IPSec tunnel mode. When we are referring to IPSec over GRE, it usually means using IPSec transport mode. But again, there is no clear cut definition in such terminology. For more information about tunnel and transport mode, take a look at this other post in which I responded to one of your posts.

    I hope this has been helpful!


  5. Rene,

    Good material in regards to GRE over IPSec. What does this command accomplish when dealing with GRE? Does this allow more bandwidth through the GRE tunnel?


    interface Tunnel40
    bandwidth 102400
    **show int tunnel40**
    Tunnel40 is up, line protocol is up
      Hardware is Tunnel
      MTU 17886 bytes, BW 102400 Kbit/sec, DLY 50000 usec,

18 more replies! Ask a question or join the discussion by visiting our Community Forum