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Muhammed-RummanehFlag for Syrian Arab Republic

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ISDN backup solution ?

HI Experts

I need your help ?

I have two Branches as following ....

- Head Office ( SHDSL Router + ISDN Router ) and those two routers connected to main server

- Branch : there is router with two type of connections ( SHDSL + ISDN )

i need to configure Branch Router ( SHDSL as main connection and ISDN as backup connection ) if first connection down the router automatically will dial-up ISDN connection

Please ...give me an advice how i can do this , and i need document for cisco router configuration

Avatar of Istvan Kalmar
Istvan Kalmar
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you need floating static route.... what tyepe of router do you have?
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Thanks for your fast response ...

Head Office : Cisco router 3845 ( for SDHSL ) and Cisco Router 2821 ( ISDN Router )
Branch : Cisco Router ( 2811 )

Thanks Again ( Istvan )

I advise to use routing protocoll for primary lines, and floating route to isdn:

route x.x.x.x 200

where is the 200 is a metric, you need to advertise default route with routing protocoll!

Best regards,

Ok .. i will try it tomorrow and i will give you a Feed back

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How is main server connected to two routers?

maain server has two network cards with different IP address

IP :
IP :

Thanks all i will try it tomorrow and  i will give you feed back

If you have a switch between main server and two routers in head office, then it is better to configure HSRP toward the main server (with tracking of route to IP subnet of workstations in Branch Office), and IGP (EIGRP, OSPF) on the WAN segment. Also you may use teaming on the server interfaces, for high availability, and use standby IP of HSRP group as default gateway of main server.