On 2007/05/17 18:44, Alex Berdan wrote:
quoted text
> This is a nice feature which can be used in cases where you don't run
> any dynamic routing protocol over GRE/IPSec tunnel.
> If you have OpenBSD as VPN concentrator you can have SNMP traps when
> the tunnel is down and take any action etc.
>
> Here is the CISCO implementation:
>
> http://www.cisco.com/en/US/products/sw/iosswrel/ps1839/products_feature_guide09186a008...
>
> Hopefully someone will see this and eventually purpose a alternate
> solution or implement keepalives in the distribution.

I already found some pages about how to turn it on in IOS, but they
don't bother with any implementation details. Thanks to a kind person
who contacted me offlist, I now know how the hack works:

http://www.cisco.com/en/US/tech/tk827/tk369/technologies_tech_note09186a008040a17c.sht...