MTU, briefly
2026-10-17
The maximum transmission unit is the largest packet a link will carry in one piece. When something along the path has a smaller limit and the signal that would tell the sender gets lost, large packets disappear while small ones get through.
The symptom is memorable: connections open fine, small pages load, and anything big hangs forever. Once you have seen it, you recognise it within a minute; the first time, it can eat an afternoon.