TCP zero windows

Yet another reason downloads can fail… Issue : Large file is being downloaded (eg an ISO running above 500MBs). The file starts off downloading fine, but eventually stops downloading, leaving the file incomplete. Cause (in this case) : TCP zero windows caused the server to reset the connection Troubleshooting : In wireshark, run the following … Continue reading TCP zero windows

TIME_WAIT and “port reuse”

Lately during some support work, a customer raised an interesting case regarding what was referred to as "port reuse". This lead to quite a nice investigation on the effect of the MSL and TIME_WAIT characteristics of TCP. So first we should define these terms and what exactly they mean. Getting an exact definition can be … Continue reading TIME_WAIT and “port reuse”