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Determining possible cause for TCP reset

asked 2019-03-01 02:22:11 +0000

Dr_Fambo gravatar image

Took a capture from my son's PC trying to connect to Apex Legends game servers. For some reason when he is connected behind my router he is unable to connect but if he is connected to the modem directly, it works as expected

I am not a WireShark or network expert but I do read and tinker in my free time. My home network is typical modem (purchased) connected to a router running OpenWRT

Using this filter tcp.flags.reset==1 and (ip.ttl==64 or ip.ttl==128 or ip.ttl==255)

I see a lot of tcp resets to the game servers with my son's PC as the source and the game servers as the destination with a ttl of 128

Any ideas what could be the culprit? This only happens with this game, any other Origin or Steam game works fine.

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After additional investigation my original question may not may not indicate a true problem

I decided to grab a tcpdump from my router and it shows my router sending an ACK back to the game server and then 11 to 14 seconds later my router sends and "Encrypted Alert" and then the connection breaks down with a RST

It looks like this

14.786405   my-router game-server   443 TCP 63  1160    4029    63132   37271 โ†’ 443 [ACK] Seq=1160 Ack=4029 Win=63132 Len=0
25.736395   my-router   game-server 443 TLSv1.2 63  1160    4029    63132   Encrypted Alert
25.736538   my-router   37271   game-server 443 TCP 63  1191    4029    63132   37271 โ†’ 443 [FIN, ACK] Seq=1191 Ack=4029 Win=63132 Len=0
25.794935   game-server 443 my-router   37271   TLSv1.2 235 4029    1192    32430   Encrypted Alert
25.795012   game-server 443 my-router   37271   TCP 235 4060    1192    32430   443 โ†’ 37271 [FIN, ACK] Seq=4060 ...
Dr_Fambo gravatar imageDr_Fambo ( 2019-03-29 01:08:09 +0000 )edit

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answered 2019-03-29 21:06:15 +0000

Ross Jacobs gravatar image

If you've isolated this problem to your OpenWRT router, I would contact their support forum to figure out why it's killing the connection.

Routers can (and do) drop and mangle packets, which looks to be the problem here.

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Asked: 2019-03-01 02:22:11 +0000

Seen: 394 times

Last updated: Mar 29 '19