HTTPS web page not loading

[LewisD1]

Hello All, 

I am experiencing a weird issue in my Multipod ACI Deployment. 

We will have 2 machines part of the same EPG/BD. 

Machine 1 and Machine 2

Machine 1 is in Pod 1

Machine 2 is in Pod 2

From machine 1 we can ping, ssh, telnet and telnet on port 443  to machine 2 without issue. When we try to load machine 2 in a web browser on port 443 we just get this page cannot be displayed. If machine 1 and machine 2 are in the same pod it all works perfectly. 

We are running version 5.2(3f)

We are not restricting Intra-EPG traffic 

I have tried disabling VRF enforcement to rule that out but still the same. 

I am drawing up a blank. 

Thanks

[LewisD1]

@Robert Burns 

I kept digging i could not get anything past over 1450MTU. It turns out that the Subinterfaces of the IPN devices had the default MTU of 1500. All other interfaces has 9126. I have changes the sub interfaces which then brought everything into life. 

You hit the nail on the head. 

Thank you for your help. 

Lewis

[Robert Burns]

Great to hear.  Since telnet worked fine (lower payload) figured a full web connection would exhibit this symptom if there was fragmentation.

Cheers,

Robert  

[Sergiu.Daniluk]

Since we are talking about unicast traffic (https), not sure why focus should be on mcast config in IPN.

@LewisD1  I would continue with the packet captures on ACI Leaf/Spines (use ELAM Assistant) and confirm first where the traffic is seen/not seen.

Since you already confirmed that the EP from Pod2 receives and responds, then continue with a captures in Pod2 (direction EP->Leaf->Spine, Source EP-Pod2 Destination EP-Pod1). Then make the same captures on Spines/Leafs in Pod1.

Cheers,

Sergiu