How to check if static Internet IP resolves to Host

cassis asked 1 year ago

My ISP is free.fr (in France) and some years ago I was assigned a static IP 85.56.185.XX.

Lately I have encountered a problem logging in to an FTP server at Fasthosts in the UK. I consulted Fasthosts and they say the issue is because my current IP does not resolve to a Host Name. We have pursued many avenues to get to this conclusion!

Free.fr (like all French Internet Service Providers) are inordinately stubborn in denying responsibility, so I wish to determine for sure that the problem is with the Free server not resolving my IP address correctly.

In order to check if my IP address resolves to a Host Name I have used Command Prompt nbtstat -A81.56.185.40 with the following result:

The same check carried out by Fasthosts gave similar results (in English):

I think that altogether this indicates that there is a problem with my Internet IP Host Name but is this definitely the case, or are there further checks?

2 Answers
Shnerdly Staff answered 1 year ago

Thanks for your question cassis.

The tests you ran will not usually show the "Resolved Name".

I used a simple freeware program called IPNetInfo provided by nirsoft to get the following result.

[img] http://www.shnerdlys.com/gallery/cassis01.jpg%5B/img%5D

The IP does indeed not have a resolved name. Many large sites block access from ip's that don't have resolved names. AOL is good for that.

If you are paying for the static IP, you should be able to have your ISP register a name for the IP. Only your ISP can do this.

MoonPoint answered 1 year ago

Your ISP needs to create a [URL="https://en.wikipedia.org/wiki/List_of_DNS_record_types#PTR"]PTR record[/URL], which is a type of [URL="https://en.wikipedia.org/wiki/Domain_Name_System"]Domain Name System (DNS)[/URL] entry used for [URL="https://en.wikipedia.org/wiki/Reverse_DNS_lookup"]reverse DNS lookups[/URL], for the IP address they assigned to you.

[QUOTE]Informational RFCs (RFC 1033, RFC 1912 Section 2.1) specify that "Every Internet-reachable host should have a name" and that such names match with a reverse pointer record, but it is not a requirement of standards governing operation of the DNS itself.[/QUOTE]

[URL="https://en.wikipedia.org/wiki/Request_for_Comments"]Request for Comment (RFC)[/URL] documents are the mechanism for setting Internet standards.

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