CSR1000v Routing between subinterfaces doesnt work in GNS3

Hi all,

I am in the process of setting up a GNS3 environment to practice CCIE R&S labs using CSR1000v routers. I am having an issue with routing traffic between sub-interfaces on the CSRs.

Here is a summary of my setup:

  1. Install GNS3 server on ESXi server
  2. Download and import CSR1000v appliance into GNS3 running IOS-XE 3.17.
  3. Create a new project in GNS3 with 10 CSR1Ks and connect them all to the built-in switch in GNS3. The built-in switch ports are configured as dot1q trunk with VLAN 1 as the native vlan.
  4. I am creating sub-interfaces on the routers using dot1q encapsulation and trying to ping each other, but it isnt working.

See sample config:

On R1:

int g 1
no ip address
negotiation auto
int g 1.12
encapsulation dot1q 12
ip address 10.1.12.1 255.255.255.0

On R2:

int g 1
no ip addres
negotiation auto
int g 1.12
encapsulation dot1q 12
ip address 10.1.12.2 255.255.255.0

Ping from R1 to 10.1.12.2 should ideally work, but it doesnt.

I have looked at the packet capture on the links and i can see the ARP requests on the links between the switch and R1 and R2.

If i perform a debug arp, i can see the arp requests going through, but the ARP response never comes back.

I have been trying a few different things with no luck:

  1. Tried a different switch like 3725 with 16 port ESW instead of the built-in switch
  2. Tried a different IOS-XE version 16.2, but that had issues with the bootup of that image.

I guess my question is if anyone has seen this problem with GNS3 and CSR1k, and have any suggestions for me?

Cheers
JK.

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