Class C IP Checker
Use this free Class C IP Checker to quickly see whether multiple domains are hosted on the same Class C IP range. That insight helps SEOs, network admins, and site owners detect shared hosting footprints, risky neighbors, and patterns in backlink networks.
Coderstool is a collection of fast, browser-based tools for developers, SEOs, DevOps, and IT teams, so you can run checks like this without installing anything.
What is a Class C IP Address?
In IPv4, an IP address is written as four numbers (octets) separated by dots, like 203.0.113.42. A Class C IP is a traditional way to group IPv4 addresses:
- Class C range: 192.0.0.0 – 223.255.255.255
- Typical subnet size: up to 254 usable host addresses per Class C network
- A “Class C block” is usually represented by the first three octets, for example:
- IP:
203.0.113.42 → Class C block: 203.0.113.*
When we talk about “same Class C IP,” we mean domains whose IPs share those first three octets (e.g., 203.0.113.10 and 203.0.113.50).
Why Check Class C IPs?
1. SEO footprint and link networks
Search engines try to detect artificial link schemes, such as Private Blog Networks (PBNs) or link farms. If many of your backlinks come from sites on the same Class C IP, it may indicate that those sites are controlled by the same owner or hosted in a tightly related block. That doesn’t automatically mean a penalty—but it weakens the appearance of diversity.
Using a Class C IP checker helps you:
- See whether your backlink sources are concentrated on the same Class C networks
- Spot suspicious link patterns (e.g., 20 domains on the same Class C IP linking to you)
- Audit client link-building campaigns for risk
2. Shared hosting neighbors
On shared hosting, many domains often sit on the same IP (and thus the same Class C block). If one of those sites is spammy, hacked, or blacklisted, it can sometimes affect:
- Email deliverability (shared mail servers / IP reputation)
- How certain security tools or filters treat traffic from that address range
- Risk level in network or firewall rules
A quick Class C check helps you understand who you’re sharing hosting resources with.
3. Network, security, and forensic analysis
For network engineers or security teams, checking Class C IPs is useful when:
- Investigating phishing or malware campaigns hosted across a narrow IP range
- Mapping infrastructure used by a particular provider or organization
- Grouping log entries or firewall events by Class C block
How to Use the Class C IP Checker
The Coderstool Class C IP Checker Tool lets you check whether several domains share the same Class C range.
- Enter domain names
- Paste 2–5 domain names
- Put one domain per line in the input box (e.g.,
example.com, example.net).
- Run the check
- Click the button to start the Class C IP test.
- The tool performs a DNS lookup and gathers IP information for each domain.
- Review the results
For each domain, you’ll typically see:- Domain / Host – the domain you entered
- IP Address – the resolved IPv4 address
- Class C IP / Block – the first three octets (e.g.,
203.0.113.*) - Status / Match indicator – whether domains share the same Class C IP range
- Interpret matches
- If multiple domains share the same Class C block, they’re more closely related at the network level (shared host, same provider node, or part of a tight subnet).
- If domains are on different Class C blocks, they’re more network-diverse.
Example Use Cases
1. Backlink audit for SEOs
- Export a list of linking domains from your SEO tool.
- Sample a subset and run them through the Class C IP Checker.
- Check if many links come from domains on the same Class C IP.
- Flag those groups as lower-diversity or potential PBN clusters.
2. Vetting a new hosting provider
- Enter your primary domain and a few competitor or test domains.
- See if you’re on the same Class C block as obvious spam or low-quality sites.
- If many suspicious domains share your block, consider upgrading to better hosting or a dedicated IP.
3. PBN and network mapping
- When investigating a potential PBN, paste several domains suspected to be connected.
- If they share the same Class C IP range, that’s one more data point suggesting common ownership or infrastructure.
4. Security and incident analysis
- From firewall or IDS logs, collect domains/IPs involved in suspicious traffic.
- Use the Class C checker to identify clusters in the same Class C block.
- Use those clusters for additional blocking rules or deeper investigation.
Tips and Best Practices
Combine with other IP & DNS tools
For a more complete picture of your network or SEO footprint, combine this Class C IP Checker with other Coderstool network tools:
- Domain to IP Converter – quickly resolve domains to their IP addresses.
- MAC Address Lookup – see vendor and range info for MAC addresses (useful on local networks).
- Network Tools hub – find utilities to check IP ranges, browser info, DNS records, and more.
You can also cross-reference with Security Tools and Web Page Tools to evaluate performance, headers, SSL, and surface-level SEO issues on the same site.
Don’t rely on Class C alone
- Class C IP similarity is only one signal.
- Always combine it with content analysis, WHOIS data, DNS records, backlink patterns, and traffic signals.
- Having multiple domains on the same Class C block is normal for many hosts; what matters is the overall pattern and intent.
Keep context: shared hosting is common
If you’re on budget shared hosting, it’s normal to see lots of unrelated domains on the same IP or Class C range. Instead of panicking, look for:
- Clear spam / adult / malware neighbors
- Very large clusters of interlinking domains with thin content
- Patterns of unnatural anchor text from those neighbors
Frequently Asked Questions (FAQ)
What is a Class C IP checker?
A Class C IP checker is an online tool that analyzes domains or IP addresses and tells you whether they share the same Class C IP block (the first three octets). It’s commonly used in SEO, hosting analysis, and network diagnostics.
How many domains can I check at once?
The Coderstool Class C IP Checker is designed for small batches. Paste a minimum of 2 and up to around 5 domains, one per line, for a quick comparison.
Does sharing the same Class C IP hurt SEO?
Not automatically. Many legitimate sites share hosting and Class C ranges. Issues arise when:
- Most of your backlinks come from domains on the same Class C block, and
- Those domains look like low-quality, spammy, or obviously connected PBN sites.
Use the tool to identify patterns, then dig deeper.
How is this different from checking exact IP matches?
- An exact IP match means two domains are literally on the same server IP.
- A Class C match means their IPs share the first three octets (e.g.,
203.0.113.10 and 203.0.113.55), suggesting they’re on the same subnet or hosting node.
Both are useful, but Class C gives a slightly wider view of network clustering.
Can I use this to choose safer hosting?
Yes. While no tool can guarantee a “perfect neighborhood,” a Class C IP checker helps you see if you’re sharing a block with lots of questionable domains. Combined with uptime, support quality, and SSL/security checks, it’s one more factor in choosing or upgrading hosting.
Related Coderstool Tools
Use the Class C IP Checker alongside other Coderstool utilities to build a fuller view of your site’s technical and SEO health:
Use these tools together to quickly troubleshoot hosting environments, investigate networks, and keep your SEO footprint as clean and diversified as possible.