Originally Posted by chiragrk
If you have a pool of IP address assigned to you, you can find that IP address range by looking at the IP Address and Subnet mask.
Hence if your server IP address is 18.104.22.168/255.255.255.248 then you have pool of IP address 22.214.171.124 - 126.96.36.199 . To find out if they've been assigned to some other machines just ping each one of them and see if you get a reply - This of course will give false positives if you have firewall blocking ICMP protocol.
Not a good way to do it, where I work, we generally assign customers a single IP in a 255.255.255.xxx range, the IPs themselves are actually port and mac address locked for our dedicated servers so customers can't steal IPs from other dedicated servers but just because the 4th octet it isn't a 0 doesn't mean this is a pool for the customer. Also a server ISP are very unlikely to assign you more then 1 or 2 IPs unless you request more, and if they are doing it properly not until the IP usage has been justified in accordance to the IP regulatory body for the region. Like ARIN for North American or RIPE for Europe.
I have experience with this and know that if an ISP didn't do this, they could soon find out one of their rivals or a disgruntled customer could then report them to said regulatory body what could lead to IP auditing. Never had to experienec and audit thankfully but as one of the people who have this role as apart of their job, I am mindful about apathy in assigning IPs to the customers.