IP tools: what they're really for
Understanding an IP address helps solve most network incidents. An IP tells you who owns it, where it seems to come from and sometimes what hostname is associated with it. With these three angles, you identify a blockage, abuse or simple misconfiguration faster. You also know what to give to technical support so they can act without wasting time.
Identify the address holder
IP WhoIs displays the organization responsible for an address range. You read the block in CIDR notation, the operator or company name and useful contacts like abuse, noc or admin. Practical for opening a ticket, reporting abuse or confirming that an IP really belongs to a specific cloud. When a redirect exists, RDAP takes over and provides the updated structured record.
Associate a name with the address
PTR reverse lookup starts from the address and goes back to a hostname. For IPv4, it translates the address into a zone name under in-addr.arpa, for IPv6 under ip6.arpa, then reads the PTR record. The interest is twofold: make your logs readable and prove the consistency of a sender server, especially in messaging. A good reverse returns a name that itself resolves in A or AAAA to the original address.
Calculate the subnet mask
The IPv4 netmask calculator accepts an address or CIDR and immediately returns the network address, broadcast, dotted-decimal mask and wildcard entry used by many ACLs. It computes usable hosts while handling edge cases such as /31 or /32 ranges. Ideal when you need to size an address plan, feed a firewall object or document a migration playbook.
See your network output
My IP address instantly displays your public IPv4 and IPv6 if your access offers them. You confirm the active version, the detected ISP and sometimes an approximate location. Useful for whitelisting an address, checking the effect of a VPN or understanding why a service sees you from another country.
Analysis method and use cases
Quick diagnosis
A site refuses you access? Start by reading your public IP, then launch a WHOIS to find the contact and the concerned block. If you send mail, check the PTR reverse resolution of the outbound address: a missing or inconsistent PTR is enough to degrade deliverability. For an application service, check that the name returned by PTR actually has an A or AAAA that points to the same address.
Security and abuse
In case of attack or spam, IP WHOIS gives you a dedicated abuse address. Attach the time, source address and log excerpts. A speaking PTR helps to quickly sort events by host rather than by number sequences. Keep in mind that an IP can be shared behind a NAT or proxy: don't confuse seen address and real author.
Operations and migrations
Before an infrastructure switch, note the outbound IP of your components and validate the reverse for MTAs that send emails. After the change, rerun "My IP address" from the concerned environments and compare. If your provider assigns you a new range, IP WHOIS confirms ownership and contacts. For a security upgrade, create explicit names on the PTR side, for example smtp01.example.net, and align the direct zones.
IPv4, IPv6, dedicated or shared
IPv4 remains ubiquitous. IPv6 progresses and becomes the default path in many networks. Seeing an IPv6 on the "My IP" page is a good sign: your network stack is ready. Many services accept both. Certain network paths, CDNs or filtering apply different rules depending on the version: testing both clarifies many situations.
A dedicated address is assigned to a single connection. It facilitates whitelists and hosting services accessible from the Internet. A shared address, typically under CGNAT at a consumer ISP, suits browsing but complicates entries from outside and blurs fine responsibility attribution. Anticipate this point for your email sending environments, your VPNs and your ACLs.
IP geolocation remains indicative. It depends on third-party databases updated at variable rates. A VPN, proxy or CDN can mask the real origin. Use this data as a signal, not as proof.
Round-trip consistency: a simple rule
For messaging and clean audits, aim for consistency: the address returns a name via PTR, and that name resolves to the same address via A or AAAA. Document everything. If you change a server's IP, remember to update the reverse and direct zone. Set a reasonable TTL: short during transition, longer once validated.
What's coming soon in IP Tools
Next improvements focus on extending the netmask engine to IPv6 with prefix compression and expanded notation, plus helpers that convert IPv4 ranges to integers for quick comparisons. Additional utilities will follow to automate routine lookups without leaving your browser.
In summary, IP Tools bring together three complementary views on an address: who owns it, what name it announces and what yours is when you test. With these elements, you make short diagnoses, contact the right team first time and keep readable logs. The rest becomes a matter of method.