After restarting an interface, im not able to ping that interface

[bobbychoi021]

As the title said, i used OSPF in my network to do routing. Theres a router that is directly connected to the internet side with 2 straight through wire. One wire is used for the primary route to the Internet, and the other is used as a backup link.

I am able to do a ping to the internet via the main link; I am able to ping the internet after shutting down the primary interface which is done via the backup route.

However, after doing a no shut on the primary interface, end devices that were used to the ping test are not able to do a ping via the primary link, but is able to do so with the backup link. 

End devices that were not used to do the ping test are able to ping the primary interface after the primary interface was restarted, but same issue occur if i were to do a ping test to the internet via the primary link again.

Is there any suggestion as to why this is happening?

I have attached the packet tracer and i would greatly appreciate if anyone could give me any advice or any help! Thank you 

[paul driver]

Hello
Probably due to nat table entries for the backup interface, try the following
clear ip nat translation * force, if thats work then decrease you nat tcp timoeut value.

ip nat translation tcp-timeout 300

[bobbychoi021]

Hi! Thanks for your reply!

I have tried your solution, but unfortunately it does not work..

[Georg Pauwen]

Hello,

I have opened your file. Which IP address on the Internet are you pinging ? And are we talking about IPv4 or IPv6 (since you have both configured) ?

There are a lot of redundancies in your network (dual OSPF processes, (floating) static routes etc.). What are the requirements, what instructions are you following ?

I have 'cleaned up' your network a bit (removed static routes/redundant OSPF/ISP 2 link to OSPF passive/enabled ip cef on all routers). 

Check if that makes a difference...

[bobbychoi021]

Hi! Thanks for trying in helping me to solve this problem!

To address your questions

1) If ISP 1 link is up, end devices will route to the internet via the g0/0/0 interface (100.1.0.1). If it is down, ISP 2 link will back it up via g0/0/2 interface (101.1.0.1).

2) So far, i have only done everything via IPV4, IPV6 does not route to internet.

3) Every network needs to have an extra route it can take in case if one network is down, hence the multiple redundancies.

4) I'm actually a student currently enrolled in a networking course. The network topology was given to us as it is and we have to make sure the requirements are met which are:

• ensure redundancies
• ospf routing
• 2 isp line, 1 for main route, 1 for backup
• able to route to WWWisp (DNS server) (ping 100.1.2.3, or www.isp.com)

I appreciate you trying to help me with my own work, but the configuration you had done for me does not work. A thing i have noticed is that - all my ip static routing done will be removed once i restart the packet tracer.

For context, I added in 2 static routes in Router1 to ensure all network is able to exit out of the network, and access to the internet. These are

ip route 0.0.0.0 0.0.0.0 100.1.0.1 (ISP1 ip address)

ip route 0.0.0.0 0.0.0.0 101.1.0.1 50 (ISP2 ip address)

Regardless of adding in an AD or not, the routes will still be cleared after a restart of the packet tracer application, and doing a show run gives me a default static route of

S* 0.0.0.0/0 [254/0] via 101.1.0.1

                    [254/0] via 100.1.0.1