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2020-05-05 13:34:50 +0000 commented answer Client and Server see different lowest MSS?

Thanks Sake. based on https://www.imperva.com/blog/mtu-mss-explained/ , this could be a valid setting when the routing i

2020-05-05 13:32:34 +0000 marked best answer Client and Server see different lowest MSS?

I am learning to use wireshark to analyze a TCP traffic and I saw something weird to me:

client capture: ( public ip 166.1.1.1, private ip 172.16.8.4 )

1        172.16.8.4     40.1.1.1     TCP   [SYN] Seq=0 Win=65535 Len=0 MSS=1460 WS=64 TSval=1963683730 TSecr=0 SACK_PERM=1
2        40.1.1.1     172.16.8.4     TCP   [SYN, ACK] Seq=0 Ack=1 Win=28960 Len=0 MSS=1440 SACK_PERM=1 TSval=568182194 TSecr=1963683730 WS=128

Server capture: ( public ip 40.1.1.1, private ip 10.240.1.10)

1        166.1.1.1   10.240.1.10     TCP   [SYN] Seq=0 Win=65535 Len=0 MSS=1452 WS=64 TSval=1963683730 TSecr=0 SACK_PERM=1
2        10.240.1.10   166.1.1.1     TCP   [SYN, ACK] Seq=0 Ack=1 Win=28960 Len=0 MSS=1460 SACK_PERM=1 TSval=568182194 TSecr=1963683730 WS=128

My question is about MSS. Client send MSS 1460, Server see it as 1452; Server send 1460, client see it as 1440. I understand MSS can be changed by a router between them, but is it normal MSS is changed to different value?

Now server will use MSS 1452 and client will use MSS 1440. I thought this could break the communication immediately since server will send tcp payload with MSS 1452, which could be dropped if the router between server and client only allow MSS 1440, but it didn't happen.

Is this normal?

2020-05-05 13:32:34 +0000 received badge  Scholar (source)
2020-05-05 13:32:29 +0000 commented answer Client and Server see different lowest MSS?

Thanks Sake. based on https://www.imperva.com/blog/mtu-mss-explained/ , this could be a valid setting when the routing i

2020-05-04 15:25:24 +0000 answered a question So im using windows 7 and i keep getting no interface found

I had same issue on Windows 10, I guess it could also happen on Windows 7. The fix is run wireshark as administrator. F

2020-05-04 14:29:12 +0000 edited answer The server sent many TCP Dup ack to client

I am new to TCP traffic analyze so I will just put my understanding here, might not be correct. Yes it will slow down

2020-05-04 14:28:51 +0000 edited answer The server sent many TCP Dup ack to client

I am new to TCP traffic analyze so I will just put my understanding here, might not be correct. Yes it will slow down

2020-05-04 14:27:46 +0000 received badge  Rapid Responder (source)
2020-05-04 14:27:46 +0000 answered a question The server sent many TCP Dup ack to client

I am new to TCP traffic analyze so I will just put my understanding here, might not be correct. Yes it will slow down

2020-05-04 12:06:54 +0000 received badge  Editor
2020-05-04 12:06:54 +0000 edited answer Client and Server see different lowest MSS?

Found a article mentioned similar case: https://www.imperva.com/blog/mtu-mss-explained/ So it could happen the client a

2020-05-04 11:48:13 +0000 received badge  Rapid Responder
2020-05-04 11:48:13 +0000 answered a question Client and Server see different lowest MSS?

Found a article mentioned similar case: https://www.imperva.com/blog/mtu-mss-explained/ So it could happen the client a

2020-05-04 01:25:56 +0000 asked a question Client and Server see different lowest MSS?

Client and Server see different lowest MSS? I am learning to use wireshark to analyze a TCP traffic and I saw something

2020-04-28 20:10:57 +0000 asked a question MacOS and TCP segmentation offload ( TSO)

MacOS and TCP segmentation offload ( TSO) I am wondering if anyone can help me to to confirm if tcpdump on MacOS can sho