Is an IOS version supporting IPSEC required to use GRE?

[aemr]

I have a 1720 with IOS 12.0.(7)T. Can I create a GRE tunnel with out upgrading the IOS to a 56bit IPSEC version? I don't have the flash or mem.

Also please provide a link to the shortcomings/vulnerabilities of GRE.

Thank you much!

Art

[gfullage]

You can use GRE in this image, you only need a crypto image if you want to use encryption on the tunnel.

GRE doesn't provide any data encryption, it only encapsulates the original packet into a GRE IP packet. The original data is still there for anyone with a Sniffer to look at.