Comment 9 for bug 1868232

+1 on this case. I worry about extending hostnames too as that typically has been a problem in the past at 63 chars disappear quickly.
In reviewing the RFC on hostnames[1] it makes sense to single minus/dash replace non-conforming characters and make sure first and last hostname chars are stripped if '-'.

The only alternative I could think of was replacing a leading or trailing '-' with an arbitrary 0 to avoid collisions with other hostnames that don't start or end with '-' if we strip characters.