Supported characters in a host name

[surendar prabu]

I am using javax.net API to make a connection to a remote server. I dont want to use the IP address but only the host name. Is there any characters that are not supported by the API , which I have to avoid while naming my server?

regards,
Surendar Prabu

[Nicholas Jordan]

/* RFC2396 specifies precisely which characters are permitted in the
* various components of a URI reference. The following categories, most of
* which are taken from that specification, are used below to describe these
* constraints:
*
*
* alpha
* The US-ASCII alphabetic characters,
* 'A'through'Z'
* and 'a'through'z'
* digit
* The US-ASCII decimal digit characters,
* '0'through'9'
* alphanum
* All alpha and digit characters
* unreserved
* All alphanum characters together with those in the string
* "_-!.~'()*"
* punct
* The characters in the string ",;:$&+="
* reserved
* All punct characters together with those in the string
* "?/[]@"
* escaped
* Escaped octets, that is, triplets consisting of the percent
* character ('%') followed by two hexadecimal digits
* ('0'-'9', 'A'-'F', and
* 'a'-'f')
* other
* The Unicode characters that are not in the US-ASCII character set,
* are not control characters (according to the {@link
* java.lang.Character#isISOControl(char) Character.isISOControl}
* method), and are not space characters (according to the {@link
* java.lang.Character#isSpaceChar(char) Character.isSpaceChar}
* method)(Deviation from RFC 2396, which is
* limited to US-ASCII)
*/