Got an Interesting Question Today

10Linefigure

Hello Everyone!

I was as an interesting question today. Can you use keepalives on encrypted GRE tunnels. My first thought was "yea of course". But when they walked away I started searching and am quite confused now.

1. "Note: GRE keepalives are not supported together with IPsec tunnel protection under any circumstances. This document discusses this issue." source: https://www.cisco.com/c/en/us/support/docs/ip/generic-routing-encapsulation-gre/118370-technote-gre-00.html

2. "When GRE is used with IPsec, the keepalives are encrypted like any other traffic" Source: https://www.cisco.com/c/en/us/td/docs/ios/12_2sb/feature/guide/sb_gretk.html < this one is along the lines of my initial response.

Note: The 2nd option is from 2006. And the first from 2017. Trust the newer documentation?

Can someone help me make sense of this please

craterman

I think if you use IOS 12 then you should trust to old document. I think if you use IOS 15 or any IOS XE then you should trust to new document. But as practice shows, it's better to check this in real environment.