[Xorp-users] static qualified next-hop-router problem

[Pavlin Radoslavov]

Adam Greenhalgh <a.greenhalgh at cs.ucl.ac.uk> wrote:

> Tuan,
> 
> You didn't say whether you were running any routing protocols.
> 
> Adam

My interpretation of Tuan's email is that the used protocol is
"static routes".

The obvious solution would be to use a dynamic protocol like RIP or
OSPF. Though, if your ISPs don't let you run any, then this is not
an option for you.

The StaticRoutes solution can't track the status of remote
gateways on its own; this is why there are dynamic protocols.

One possible work-around hack is to use an external script that
helps StaticRoutes tracking the status of the gateways.

The script will run a periodic ping to the primary gateway. If the
ping fails, then the script will use xorpsh to reconfigure XORP by
changing the next-hop address to the secondary gateway.

Hope that helps,
Pavlin

> On 09/01/2008, Tuan Hoang <tuan.hoang at agilecommunications.com> wrote:
> >
> >
> >
> > Hi,
> >
> > I'm using a XORP 1.4 under CentOS 4.5.  I have a router connected to two
> > ISP's and want to detect when my primary gateway is down on eth1 (Note:
> > ethernet link is still up but gateway is unreachable) and then switch over
> > my default route to my other ISP's gateway on eth2.
> >
> > I have the static route configured with the a simple next-hop-router to eth1
> > with ISP1's GW and also a qualified next-hop-router to eth2 with ISP2's GW.
> > When I turn off my cable modem to ISP1, XORP does not change my default
> > route's GW to ISP2's GW on eth2.  The only way I've gotten this to work is
> > by removing the eth1 ethernet cable to cause the interface flags to change.
> >
> > FWIW, I've made sure that the ARP cache is flushed for the ISP1 GW.
> >
> > Thanks,
> > Tuan
> >
> > P.S.  Please reply all since I am not subscribing to the list.
> > _______________________________________________
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> >
> >
> 
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