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The window scale factor and the TCP window as a whole have nothing to do with MTU discovery. TCP reception window has to do with memory buffer at the recipient side while MTU has to do with frame size on various network segments along the path, where encapsulations (PPPoE, VPNs) occupy part of the Ethernet frame so a smaller part remains available for the payload.

There is no way to see that something (like e.g. the icmp "packet too big" message) is missing in the capture - you may find out by symptoms, i.e. that smaller packets do get through (means get acknowledged in case of TCP) while larger don't. If you have some possibility to manipulate the MTU or MSS on sending side, you can reduce it there and if that helps, you can be almost certain that the icmp "packet too large" doesn't pass through somewhere on the network path between your equipment and the remote server. If you have issues with any server, your ISP is most likely the guilty one.

The window scale factor and the TCP window as a whole have nothing to do with MTU discovery. TCP reception window has to do with memory buffer at the recipient side while MTU has to do with frame size on various network segments along on the path, where path between the two endpoints (client and server). E.g., some encapsulations (PPPoE, VPNs) occupy part of the Ethernet frame so a smaller part of it remains available for the payload.

There is no way to see that something (like e.g. the icmp "packet too big" message) is missing in the capture - you may find out by symptoms, i.e. that smaller packets do get through (means get acknowledged in case of TCP) while larger don't. If you have some possibility to manipulate the MTU or MSS on sending side, you can reduce it there and if that helps, you can be almost certain that the icmp "packet too large" doesn't pass through somewhere on the network path between your equipment and the remote server. If you have issues with any server, your ISP is most likely the guilty one.

The window scale factor and the TCP window as a whole have nothing to do with MTU discovery. TCP reception window has to do with memory buffer at the recipient side while MTU has to do with frame size on various network segments on the path between the two endpoints (client and server). E.g., some encapsulations (PPPoE, VPNs) occupy part of the Ethernet frame so a smaller part of it remains available for the payload.

There is no way to see that something (like e.g. the icmp "packet too big" message) is missing in the capture - capture. But you may find that out by symptoms, i.e. that smaller packets do get through (means get acknowledged in case of TCP) while larger don't. If you have some possibility to manipulate the MTU or MSS on sending side, you can reduce it there and if that helps, you can be almost certain that the icmp "packet too large" doesn't pass through somewhere on the network path between your equipment and the remote server. If you have issues with any server, your ISP is most likely the guilty one.