Hostname vs. IP - address

Question

I am currently implementing openssl into my application. My problem arose when I had to set the hostname, IP - address, and port of the BIO. I have always known ip and hostname to be the same thing. Could someone please explain the difference.

Solution

A host name is a combination of the name of your machine and a domain name (e.g. machinename.domain.com). The purpose of a host name is readability - it's much easier to remember than an IP address. All hostnames resolve to IP addresses, so in many instances they are talked about like they are interchangeable.

Comments

[trnelson]

Just wanted to add that a host name resolves to an IP address by DNS. Not fully relevant to the question but kind of brings this answer full circle.

[Admin]

You saying that a hostname resolves to an IP makes me think that they are the same again

[Jim Davis]

Say your name is Steve and your phone number is 555-1212. DNS is the phonebook. I can "call steve" or I can "call 555-1212" and get the same result. One's a name, one's an address.

[ChristophK]

Downvote for "A host name can have multiple IP addresses, but not the other way around". It's possible, see serverfault.com/questions/65781/multiple-reverse-dns-entries‌​.

[Paul Whipp]

They are not the same: The hostname is a mapping to the IP address. Over time the same hostname could map to a different IP address. This might be done where a web service is rebuilt on a different machine for example. In Jim's example, Steve might change his phone number but he would still be Steve.