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Default Route Question


Can anyone tell me if there is a way to tell what traffic uses the default route?

I need this information because I am in the middle of a migration project. I need to remove the default route at the end of the project because of security concerns, however I want to be able to see if I am missing any routes by identifying what traffic is using the default route!

Is this possible?

Help well rated.


  • WAN Routing and Switching

Re: Default Route Question


You can combine the usage of ip cache flow and show ip route for this issue, and any Network not in table uses the default route for sure, but the point is if it is a security concerns then it should be done in a reverse way, and thus you should only have routes for the destinations granted access by your security policy.


Mohammed Mahmoud.

Re: Default Route Question

HI Gavin, [Pls rate if HELPS]

Static Routes:

Static routes are special routes that the Technician manually enters into the router configuration. You could build an entire network based on static routes. The problem with doing this is that when (not if!) a network failure occurs, the static route will not change without you performing the change.

Default Route:

Default route is one that is used when no matching routing table entry is found. It appears in the routing table as a route to network and you know it is set when the output of "sho ip route" contains an entry similar to the following entry at the top of the routing table:

Gateway of last resort is to network

Any packet whose destination address is not matched by any specific routing table entry will take the path to the gateway of last resort. The gateway of last resort is a router that has more complete routing information and can hopefully forward the packet to its destination. If there is no default route and the packets destination address is not found in the routing table, then the packet is dropped and an ICMP Destination or Network Unreachable is returned to the source IP address.

INFO:show ip route command will be helpful to understand the Traffic Pattern that uses your default Route.

Based on your Network Requirement & above Definition you could proceed further.

Pls Rate if Helps

Best Regards,

Guru Prasad R

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