Duplicate ICMP replies from Xbox

[NH_X4S_AC2600]

Was trying to troubleshoot some network errors after my spouce had TWC "assist" with the cable modem.

After sorting out the issues TWC caused (Side rant here: (reset the modem, disabled firewall, removed ip filtering, and turned on a DHCP service despite being a bridge modem, reset password to the default, and generally left everything wide open) I noticed that I was getting duplicate icmp from my XBox one. 

64 bytes from 10.10.1.90: icmp_seq=418 ttl=128 time=4.973 ms

64 bytes from 10.10.1.90: icmp_seq=418 ttl=128 time=4.996 ms (DUP!)

When I pull up more detail in wire shark I can see the replies as duplicates to the request.  From my review of the details the only differences in the duplicate request is the message identification, which makes sense as it is a separate reply. 

More troubleshooting steps I have taken trying to isolate the issue:

- Created XBox specifc port forwarding and then removed. 

- Cleared arp aches on all networked devices with tables 

- Removed all other devices from the network

- Reset the Xbox

- Changed dhcp ip reservation schemes

- Turned UpNP on/off

- Restarted all devices (had to say it)

Am stumped.  What am I missing?

[NH_X4S_AC2600 · Accepted solution]

The DUP! error occurred wired or wireless.  

Also isolated the cause on the XBox client identifying the symptoms only occurred during a multi-player game and not during one player connection or background downloads.

I think I narrowed it down to the MTU size on the netgear router.  To make it work for one client device reducing the mtu size for the entire router seems silly.   Perhaps NG will come out with a variable/dynamic sizing in the future.

To identity the issue I sent pings using -D and -s and reduced packet size unit I had the largest multiple of 8 that did not produce an error. 

[ElaineM]

Hello @NH_X4S_AC2600

Welcome to the community!

How is the Xbox connected, wired or wireless?

How many Xboxes are connected?

See this link if it will help.

[NH_X4S_AC2600 · Accepted solution]

The DUP! error occurred wired or wireless.  

Also isolated the cause on the XBox client identifying the symptoms only occurred during a multi-player game and not during one player connection or background downloads.

I think I narrowed it down to the MTU size on the netgear router.  To make it work for one client device reducing the mtu size for the entire router seems silly.   Perhaps NG will come out with a variable/dynamic sizing in the future.

To identity the issue I sent pings using -D and -s and reduced packet size unit I had the largest multiple of 8 that did not produce an error. 

[ElaineM]

So adjusting the MTU helped?