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fmarshall
Beginner

RV042 ICMP Redirect

I don't know when RV042 started sending LAN clients ICMP Redirect messages.

It drove me nuts today trying to figure out what was going on!!

I want to disable it.  How?

Here is the situation:

For years, we've interface our subnets with RV042 routers (using an interim subnet in the common connections).

One subnet / primary site / normally contains the internet gateway.  The other subnets get internet traffic from this primary internet connection.

Their default packets get sent via the RV042s to the primary site.  

At the secondary sites, the RV042 is also the default/internet gateway.

Also, the RV042s carry intersite traffic.  So there is a static route in the RV042 for each other site.

This works fine.

We have configured a "standby" RV024 for each of the secondary sites in the case that the main site loses internet service.

(Each of the secondary sites have their own internet service).

The job for the standby RV042 router is to:

- Replace the "normally used" RV042 at that site.

- Continue to direct inter-subnet packets to the intersite connection as always.

- Direct outgoing internet traffic arriving from the LAN clients to the site's internet firewall / secondary gateway.

 

I was testing new firmware on these standby RV042s and, to my surprise, they wouldn't work for the subnet-to-subnet intersite traffic!  Now, I figured that the router had to be the problem but found if I could reboot a client, it would then be able to reach the other subnets.

A traceroute revealed that the next hop was NOT the RV042 as intended.  Rather, it was the secondary gateway providing internet service.  Intersite packets intended for the RV042 were skipping it!!  And, thus intersite traffic was stopped.

I found that rebooting the client computer would fix the problem - but this is NOT a good production solution!

 

Wireshark helped us see that the client was using the secondary gateway as THE gateway!!

It appears that ICMP redirect was sent from the RV042 to the client - that's what seems to cause this.

So, we want to turn it off.

How?

 

 

 

 

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