What are the allowed characters in a subdomain?

Question

What characters are you allowed to use in a subdomain?

Example: for someSub.example.com the someSub portion.

I know you can use le

Answer 1

Letters (except stressed à), Numbers 0-9 and Hyphen.

http://en.wikipedia.org/wiki/Domain_name excerpt: Valid characters that can be used in a domain name are:

a-z
0-9
- but not as a starting or ending character
. as a separator for the textual portions of a domain name

From http://tools.ietf.org/html/rfc1035

Various objects and parameters in the DNS have size limits. They are listed below. Some could be easily changed, others are more fundamental.

labels          63 octets or less
names           255 octets or less
TTL             positive values of a signed 32 bit number.
UDP messages    512 octets or less