SRX Services Gateway
Reply
Contributor
radius
Posts: 19
Registered: ‎12-29-2009
0

SRX210-H Failover between 2 ISPs with fallback

Hello, I have setup my SRX210 to use as default router a 'static route 0.0.0.0/0 qualified-next-hop [IP-A]' and as next-hop [IP-B]. This crates the conditions for a failover in case the interface/line/device with IP-A falis.

The failover works fine even if the ethernet interface is up but the connectivity due to line problem is down. Therefore -as expected- all traffic from gateway with IP-A is re-routed to gateway with IP-B. The second gateway device is a prototype Juniper wipipe CX-111 device that offers 3G wireless backup. This device works like a charm. As soon as it senses incoming traffic it enables the 3G interface and the failover is almost seamless. The wipipe device is able to sense when it is no longer needed and it shuts down the expensive 3G link after a defined pperiod of inactivity going to stand-by till the next time that it will be needed. All these are great, but my problem is this: I look for a way to make the SRX sense that the initial (qualified) line is back up again and therefore change the default route back to IP-A, in turn letting the wipipe device unused to shut down after some time of inactivity.

Is there a way to make the SRX monitor the line status and change the default router? With my current setup after the failover there is no fallback evidently because there is no mechanism to sense that line with IP-A is up again.

 

Current setup:

routing-options {
    static {
        route 0.0.0.0/0 {
            next-hop [IP-B];
            qualified-next-hop [IP-A];
        }
    }
}

Any ideas are welcome.

Thanks.

Visitor
jochr
Posts: 3
Registered: ‎09-13-2010
0

Re: SRX210-H Failover between 2 ISPs with fallback

Did you find a fix to this problem? I'm searching for a solution to a similar problem.

 

Jo Christian

Visitor
routeruser
Posts: 8
Registered: ‎12-17-2009
0

Re: SRX210-H Failover between 2 ISPs with fallback

you can solve this problem using a junos event script.

 

here is a link to how to write one ....

 

http://www.juniper.net/us/en/local/pdf/day-one-guides/7100110-en.pdf

 

The logic would be to to do a ping sourced from ISP-A interface to a know IP. This ping will fail as long as ISP-A is down. Once the ping works, you can change the routing table extries/preference.

 

Ofcourse this should be the logic of the script and the script will change the routing table entry once the ping works.

Contributor
FLOW
Posts: 16
Registered: ‎01-09-2011
0

Re: SRX210-H Failover between 2 ISPs with fallback

Did some one finished an effctive event script ?

 

Grüße

FLOW

Super Contributor
colemtb
Posts: 312
Registered: ‎09-30-2009
0

Re: SRX210-H Failover between 2 ISPs with fallback

The CX111 had a script available for DL that does just this if I understand the situation correctly...  I might not but...

 

http://www.juniper.net/us/en/local/pdf/app-notes/3500184-en.pdf

 

Read Page 10. 

 

Script.

 

www.juniper.net/support/products/cx/#sw

 

 

Copyright© 1999-2013 Juniper Networks, Inc. All rights reserved.