This post is still related or somewhat helpful to our virtual web hosting/how to start a blog series of post. The Reverse IP Domain Lookup tool will help you determine information about your shared web server.
If you do a quick Google search for ‘reverse IP domain lookup‘, you’ll see that there are more than a couple of websites that offer such a tool.
The specific website I’ll be mentioning here is The Same IP, which is also the same as the commercial type.
THE SAME IP
What The Same IP do basically is to check the multiple PTR record for a particular domain on it’s authoritative domain name server.
While most rDNS entries only have one PTR record, it is perfectly legal to have many different PTR records. However, having multiple PTR records for the same IP address is generally not recommended unless there is a specific need. For example, if a webserver supports many virtual hosts, there can be one PTR record for each host and some versions of name server software will automatically add a PTR record for each host.
Multiple PTR records can cause a couple of problems, including triggering bugs in programs that only expect there to ever be a single PTR record and, in the case of a large webserver, having hundreds of PTR records can cause the DNS packets to be much larger than normal.