[LARTC] DGD patch not detecting dead gateway

[Grant Taylor]

On 01/19/07 12:45, Manish Kathuria wrote:
> My experience has been mixed. The patch worked very well in many cases
> but in some it worked only if the first hop gateway was down and not
> any of the subsequent hops. So as you mentioned its happening since it
> can ping the switch / modem, it thinks the link is good. You can make
> a script which will keep on running in the background and check it the
> links are up or not and if any of the links is down, it can change the
> default route and provide a failover.

I have been tasked with writing such a script.  In my scenario, I'm 
taking it a bit further though.  I am planing on having my script test 
the actual service that I'm trying to connect to.  I.e. connect to port 
80 and request a page.  I'm having to go this route because I've had 
sporadic MTU issues in one of our (primary) paths.  The provider is 
suppose to be repairing the problem, however I need a solution before 
that can happen.

I am planing on writing a small daemon, probably in Perl, that will run 
the tests.  What I don't have a good way to do is alter the routing 
tables, short of shelling out and running ip directly.  I would like to 
know if any one knows of any other way to alter the routing tables / 
rules short of calling a shell command.



Grant. . . .