Enter up to 40 Domains (Each Domain must be on separate line)
Class C IP Checker resolves a list of domain names to IPv4 addresses and compares the first three octets of those addresses. It is useful when you need a quick technical view of whether several domains currently resolve to the same apparent /24 IPv4 prefix.
Enter one domain per line and run the check. The report displays each valid domain, its resolved IP address, and the three-part prefix derived from that address. Domains that show the same prefix can be identified easily in the results.
The name “Class C” is based on historical classful networking terminology. Modern internet routing uses Classless Inter-Domain Routing, commonly called CIDR. For that reason, the checker’s three-octet value is best understood as a convenient /24-style comparison, not proof that the address belongs to a formally assigned Class C network.
The checker processes the submitted domains individually. For every valid entry, it performs a DNS lookup, obtains the IPv4 address returned by the server, and creates a comparison value from the first, second, and third octets.
For example, if one domain resolves to 203.0.113.15 and another resolves to 203.0.113.92, both produce the prefix 203.0.113. That means their returned IPv4 addresses fall within the same apparent 203.0.113.0/24 range. It does not necessarily mean that the domains have the same owner, use the same physical server, or share the same hosting account.
The output is a DNS and IP comparison. It does not:
You can include protocol or www variations, but the tool normalises valid entries before resolving their hosts. Each non-empty line is processed separately. An invalid or non-resolving entry may not produce a useful result.
The domain column identifies the hostname that was accepted for the lookup. Confirm that it matches the domain you intended to test, especially when similar names or different subdomains are involved.
The IP address is the IPv4 value returned by the resolver at the time of the check. DNS records can change, and a domain may use multiple addresses. A later lookup from another location or resolver may therefore return a different result.
The prefix is created by removing the final octet from the returned IPv4 address. Matching prefixes show that the observed addresses are in the same apparent /24 block. Non-matching prefixes show that they are in different blocks at that comparison level.
A content delivery network can route a domain through shared edge infrastructure. Several unrelated domains may therefore resolve to the same network or IP address. The origin server may be hidden behind the CDN and cannot be identified from the public address alone.
A website can distribute traffic across several servers. DNS rotation, geographic routing, failover systems, or load balancers may return different addresses across requests. A single lookup is a snapshot rather than a complete inventory.
Shared hosting commonly serves many independent domains from the same infrastructure. A matching IP or prefix can indicate shared infrastructure, but it does not establish a business relationship between the websites.
When a site changes providers, moves to a CDN, or updates its origin, DNS records may point to a new address. Cached DNS information can also cause old and new results to coexist temporarily.
This checker’s comparison is designed around IPv4. A domain that uses only IPv6 may not produce the expected output. The tool also uses the address supplied by its resolver and may not list every address published for the domain.
A shared IPv4 address or matching three-octet prefix is not, by itself, evidence of an SEO problem. Shared hosting, cloud platforms, reverse proxies, and CDNs routinely place unrelated websites on common infrastructure. The IP comparison alone cannot show whether a page is useful, trustworthy, crawlable, or eligible to rank.
Do not assume that another website’s poor content automatically transfers a penalty to every domain using the same IP range. Search performance should be investigated through the website’s own content, technical accessibility, security, manual actions, indexing reports, and search performance data.
If a website experiences access or crawling problems, focus on measurable hosting conditions such as outages, slow responses, DNS failures, TLS errors, firewall blocks, rate limits, and server errors. These issues can affect users and crawlers directly. A matching prefix without such evidence is not a reason to move hosting.
These are starting points for investigation. Confirm important findings with DNS records, hosting documentation, server configuration, and information from the responsible provider.
Older IPv4 documentation divided address space into fixed classes, including Class A, Class B, and Class C. A traditional Class C network used 24 bits for the network portion and 8 bits for host addresses, which visually corresponds to comparing the first three octets.
Modern networks do not depend on those fixed classes. CIDR allows network prefixes of different lengths, written with slash notation such as /24, /22, or /28. Two addresses sharing the same first three octets may look like they share a /24, but the provider’s actual allocation and routing design may use a different prefix length.
For everyday comparison, “Class C IP Checker” remains a familiar tool name. Technically, however, the displayed value should not be treated as authoritative subnet or ownership information.
A matching prefix can arise for many reasons. Domains may share a host, use neighbouring addresses from one provider, sit behind the same CDN, or receive addresses from a large cloud platform. Conversely, related websites can appear on completely different prefixes because they use different regions, providers, or delivery networks.
IP evidence should therefore be combined with reliable administrative information. DNS records can show how a hostname is configured. Registration data may identify a registrar or nameserver provider, although privacy protection limits ownership conclusions. TLS certificates, HTTP headers, and hosting records can provide clues, but none should be used alone to claim common control.
No. It resolves only the domains you submit and compares their returned IPv4 addresses. It does not perform reverse-host discovery for every domain sharing an address.
No. Shared hosting, CDNs, and cloud providers can place unrelated websites within the same IP range. Matching results show network proximity at the chosen comparison level, not ownership.
No. A blacklist check requires querying specific reputation or blocklist databases. This tool performs domain resolution and prefix comparison only.
A shared address or prefix alone does not demonstrate a ranking penalty. Investigate your own website’s content, indexing, accessibility, security, and Search Console reports instead of assuming guilt by IP proximity.
The site may use load balancing, a CDN, geographic routing, dynamic infrastructure, or a new hosting provider. DNS updates and caching can also cause different results over time.
The displayed three-octet comparison is an IPv4 concept. It is not an IPv6 subnet calculator, and an IPv6-only domain may not produce the expected result.
Class C IP Checker provides a quick comparison of domains, resolved IPv4 addresses, and three-octet prefixes. It is useful for preliminary DNS and hosting observations, but it is not a reputation, security, backlink, ownership, or ranking tool. Treat every result as a time-specific technical snapshot and verify important conclusions through authoritative DNS and hosting information.