GRE and VPN

[PinkLips]

In Cisco, what is Generic Routing Encapsulation used for?
I know what building a VPN tunnel is, but how is that different from GRE?


Thanks,
Nicole

 

[lgarner]

It's typically used to encapsulate other protocols into IP. As I recall, the main difference is that it's not encrypted.

For example, I use it in addition to a VPN to make two routers which are on opposite ends of a Pix VPN appear as neighbors for the purpose of EIGRP.

 

[nedbert9]

GRE is the underlying protocol for IPSec.

nedbert9
A+, CCNA, CNE 3-5, MCSE NT4, MCP 2003
A leisurely lifestyle is a sign of wisdom and maturity - Aristotle

 

[nedbert9]

Correction.

As LGARNER says it's an encapsulation protocol for IP routing other protocols.

It can be used to encapsulate traffic like IPsec.

nedbert9
A+, CCNA, CNE 3-5, MCSE NT4, MCP 2003
A leisurely lifestyle is a sign of wisdom and maturity - Aristotle

 

[nedbert9]

ARRGGGG!

Today I am doubly wrong!

PPTP, Point to Point Tunneling Protocol, is based on GRE.

Different, but based on it.

Don't listen to me today!

Here's a VPN, PPTP and GRE info for you. Hopefully, this will redeem myself.

http://www.microsoft.com/windows200...chinfo/reskit/en-us/intwork/inbe_vpn_NAXE.asp

nedbert9
A+, CCNA, CNE 3-5, MCSE NT4, MCP 2003
A leisurely lifestyle is a sign of wisdom and maturity - Aristotle

 

[Jynxx]

We use GRE to encapsulate traffic for VPN/PRN links, so that we can have full OSPF routing/adjacency.

Impossible without GRE tunnels.