03-24-2003 01:00 AM - edited 03-02-2019 06:04 AM
How I can configure NAT over backup interface ISDN BRI?
03-24-2003 08:27 PM
Here is the url for sample config for isdn BRI backup using "backup interface"
http://www.cisco.com/warp/public/793/access_dial/backup_11047.html
Once you have that, you can use following link as a sample config to configure NAT over bri line
03-25-2003 06:54 AM
Thank you for you interest, but it doesn't solve my problem. I have two interfaces, the first one is primary (int. serial), the second one is backup (ISDN BRI), here is the configuration:
!
interface FastEthernet0
ip address 192.xxx.xxx.xxx 255.255.255.0 (private)
ip nat inside
!
interface Serial0
backup delay 10 10
backup interface BRI0
ip address xxx.xxx.xxx.xxx 255.255.255.252 (public)
ip nat outside
!
interface BRI0
ip address xxx.xxx.xxx.xxx 255.255.255.0 (public)
ip nat outside
encapsulation ppp
dialer string 971100811
dialer load-threshold 1 either
dialer-group 1
service-policy output term
isdn switch-type basic-net3
no cdp enable
ppp authentication chap pap callin
ppp chap hostname IBM
ppp chap password 7 xxxxxxxxxxxxxxx
ppp pap sent-username IBM password 7 xxxxxxxxxxxxxxx
ppp multilink
!
ip nat inside source nonat interface Serial0 overload
ip nat inside source list 1 interface Serial0 overload
!
ip route 0.0.0.0 0.0.0.0 Serial0
ip route 0.0.0.0 0.0.0.0 BRI0
!
access-list 1 permit 192.168.0.0 0.0.0.255
!
When the primary interface goes down, the backup goes up. That's good, but the privite network (PC) can't go to the Internet! NAT doesn't function. You can't set up second ip nat command. How I can solve this problem?
Thank you for your answer !!!
Jakub Chytracek
03-25-2003 08:44 PM
First of all you need to add following command as i don't see it in the config.
ip nat inside source list 1 interface bri0 overload
Once you have that NAT over bri should work fine. Once the serial interface is down, the default route to serial interface will be flushed from the routing table and willbe replaced by default route to bri0 interface.
03-25-2003 11:24 PM
Of course I tried it before, but it also doesn't work, because if you set second NAT command, you overwrite the first one.
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