How to resolve the proper IP address of a server?

Question

The server is "dlftp_int.danlawinc.com" tracert is only giving 192.168.x.x addresses. I want the proper IP address; which online tools cannot seem to provide because of the underscore in the name.

Answer 1

The server is dlftp_int.danlawinc.com

That is an invalid domain name - _ is not an allowed character.

That is why the online tools remove this character (and other not allowed characters) when you try and use them.

Using this character may work on private networks but will fail if the server needs to be exposed to the public internet.

According to RFC 1035 - Domain Implementation and Specification each part of a domain (or label) must start with a alpha character, end with an alpha or numeric character, and include only alpha, numeric or - (hyphen) characters.

See section 2.3.1 of RFC 1035:

<domain> ::= <subdomain> | " "

<subdomain> ::= <label> | <subdomain> "." <label>

<label> ::= <letter> [ [ <ldh-str> ] <let-dig> ]

<ldh-str> ::= <let-dig-hyp> | <let-dig-hyp> <ldh-str>

<let-dig-hyp> ::= <let-dig> | "-"

<let-dig> ::= <letter> | <digit>

<letter> ::= any one of the 52 alphabetic characters A through Z in
upper case and a through z in lower case

<digit> ::= any one of the ten digits 0 through 9

Note that while upper and lower case letters are allowed in domain names, no significance is attached to the case. That is, two names with the same spelling but different case are to be treated as if identical.

The labels must follow the rules for ARPANET host names. They must start with a letter, end with a letter or digit, and have as interior characters only letters, digits, and hyphen. There are also some restrictions on the length. Labels must be 63 characters or less.

The historical reason is that domain names are not case sensitive - and on many keyboards _ is the same as shift-