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New Member

Help with routing problem


I have a routing problem

the esenarios are the following:

I have 2 Links to internet, the first is a v.35 link with 512kbps include a IP LAN pool, and the second is a ADSL link with dynamic IP.

The first link is used for a VPN L2L, Client VPN and some static nat's.

The second link is used for a internet navigation (NAT).

I have 2 different's NAT's (Dialer interface and Pool).

no have a routing protocol, all is with static routing.

I have a problem if I configure 2 route default for the different's links and different's the NAT, because all traffic exit by the serial interface

ip route Dialer1

ip route

and I have a problem if I configure a route-map for nat because the VPN's fails, I don't know if I am configuring bad the route-map's or I need configure aditional parameter in the VPN, NAT or general configuration.

I need a configuration so that router it makes the decision to send traffic by the correct interface, depending on the characteristics of the traffic's, and if it is possible to establish a configuration so that in case of fault of the ADSL link, navigation uses a backup NAT and exit by the serial interface.

I Attach the actual configuration and diagram, with this configuration if the ADSL fails, all VPN clients fails, don't have backup nat and the VPN client traffic return, exit by the dialer interface


Re: Help with routing problem

A route-map should do it, but I don't even think you need that. Am I right to say that if destination is a specific internet address then it should go via Dialer1 (ADSL), else it should go via s0/0/0?

ip route [destination subnet & mask] Dialer1

ip route serial0/0/0

A possible backup route:

ip route Dialer1 200

New Member

Re: Help with routing problem

I need that both connections work at the same time but with crossing different traffics.

The first connection is due to use for VPNs and Static NAT's for public services FTP, HTTP (serial 0/0/0).

the second connection is only for navigation (dialer 1).

The backup that I need is in case the navigation connection fails (dialer 1), the traffic of navigation leaves by the first connection (serial 0/0/0).

Additionally I have a problem when fails the second connects ISP-2, the VPN clients and Statics Nat's not operate.

New Member

Re: Help with routing problem


Unfortunately you task very complex and have many detail. I think, to solve it is require access for config & troubleshoute.

I give you example config for simple case with 2 ISP connection. Hope this help.

Example (multi-homing to 2 ISPs):

Switch to redundant ISP2 if main ISP1 fail.

For simplicity assume only outbond internet traffic exist.

!You should config 2 routes-

ip route

! Next route is backup

ip route 250

ip nat inside source route-map isp1-nat interface overload

ip nat inside source route-map isp2-nat interface overload

route-map isp1-nat permit 10

match interface

route-map isp2-nat permit 10

match interface


ip nat inside


ip nat outside


ip nat outside


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