I want to validate hostnames (ie x.y.z format). Currently I'm using the regular expression below, but it is not working.
It accepts x.y.z.a etc. I want to restrict it to only accept x.y.z. Does anyone know how I can fix it?
/^([a-z0-9]+(-[a-z0-9]+)*\.)+([a-z]{2,12})$/i
Just replace the + modifier with {1,2}:
/^([a-z0-9]+(-[a-z0-9]+)*\.){1,2}([a-z]{2,12})$/i
And, if you don't need the capture groups:
/^(?:[a-z0-9]+(?:-[a-z0-9]+)*\.){1,2}[a-z]{2,12}$/i
If you want exactly 3 parts (x.y.z), use {2} instead of {1,2}
/^(?:[a-z0-9]+(?:-[a-z0-9]+)*\.){2}[a-z]{2,12}$/i
This will do the job. Above regex will match only x.y.z format
^([a-z0-9]\.){2}[a-z0-9]$
Two times x. format with a x at the end.
