Forcing a packet through an interface (OT?)

Mario Lobo mario.lobo at
Mon Jul 11 19:53:23 GMT 2005

Forgive me if this is off-topic.

How could I force a packet to go out through an interface, 
despite the default route?

Suppose I have two interfaces connected to the internet:

1) rl0 ( ---> ISP x

2) rl1 ( ---> ISP y

ISP y is just a backup link. ISP x is the working link. 
Don´t want to load-balance them.  Use 2) ONLY if 1) is out.

Suppose 1) is down. I switch to 2). But I have to keep testing 1)
to see when it comes back up. How could I force a packet (ping maybe?) 
to through 1), despite the default route being 2) ?

I am aready binding the ping packet to the IP I want but that´s not enough.

any suggestions?

   //|  //||
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-//--//---|| ARIO LOBO
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mario.lobo at

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