- /* mtuprobes == 0..89: initial discovery, send bursts with 1 second interval, mtuprobes++
- mtuprobes == 90: fix MTU, and go to -1
+ /* mtuprobes == 0..19: initial discovery, send bursts with 1 second interval, mtuprobes++
+ mtuprobes == 20: fix MTU, and go to -1