SSL
SSL Checker
Inspect a live website certificate, issuer, SAN coverage, TLS details, chain and expiry date.
Open toolFast, focused network checks
Diagnose faster.
Verify clearly.
A practical browser toolkit for addressing, DNS, SSL/TLS, HTTP security, reachability, public network data, and everyday engineering tasks.
29 utilitiesfree browser tools
9 task groupsorganized by engineering job
No setupopen and run a check
Showing all 29 tools and tests.
SSL
Bulk SSL Checker
Audit certificate verification, HTTPS status and expiry for up to 500 hostnames.
Open toolSSL
Certificate Decoder
Decode pasted PEM certificates and inspect public certificate fields without a live scan.
Open toolSSL
Certificate Chain Composer
Find missing intermediates and assemble a correctly ordered fullchain.pem.
Open toolHTTP Protocol
HTTP Header Checker
Inspect status, redirects, cache policy, cookies and response headers.
Open toolHTTP Protocol
HTTP Response & Timing Analyzer
Measure DNS, TCP, TLS, TTFB, content transfer and redirect overhead.
Open toolHTTP Protocol
CORS Tester
Test Origin, preflight, requested methods, headers, credentials and browser access policy.
Open toolHTTP Protocol
Security Headers Checker
Review HSTS, CSP, clickjacking, MIME, referrer and permissions headers.
Open toolHTTP Protocol
Regex Generator & Tester
Build and validate JavaScript regular expressions with live matches, groups, replacement previews, explanations, and examples.
Open toolTests
Networking Tests
Browse focused practice tests for CCNA, routing, switching, IPv6 and troubleshooting.
Open toolTests
Routing Practice Test
Test OSPF, BGP, EIGRP, RIP, route selection and troubleshooting knowledge.
Open toolIP Protocol Tools
IPv6 Compress & Expand
Validate IPv6 notation and convert between canonical compressed and full eight-group forms.
Open toolIP Protocol Tools
Subnet Calculator
Calculate network address, broadcast, usable hosts, masks and CIDR ranges.
Open toolIP Protocol Tools
Summary Address Calculator
Combine IPv4 networks into one covering CIDR and inspect the bitwise common-prefix calculation.
Open toolIP Protocol Tools
IP Location Finder
Check approximate location, ASN, ISP and organization for a public IP address.
Open toolIP Protocol Tools
IP Blacklist Checker
Check an IP address or mail infrastructure against configured DNS-based blacklists.
Open toolIP Protocol Tools
ASN Lookup
Find the route prefix, registry, ASN and network owner for an IP or hostname.
Open toolIP Protocol Tools
WHOIS Lookup
Inspect public RDAP and WHOIS ownership, allocation and registration data.
Open toolIP Protocol Tools
Ping & Latency Checker
Check public reachability, response time and packet loss with controlled limits.
Open toolIP Protocol Tools
Traceroute Tool
Trace a limited public network path and review responding hops and timeouts.
Open toolIP Protocol Tools
TCP Port Checker
Test one authorized public TCP port without ranges or bulk scanning.
Open toolIP Protocol Tools
Wildcard Mask Finder
Convert subnet and wildcard masks for ACL and routing configuration work.
Open toolOther Tools
Is Website Down? Checker
Check whether a public website responds and review status, timing, redirects and final URL.
Open toolOther Utilities
DNS Propagation Checker
Compare DNS answers, TTL, latency, and resolver consistency across public networks.
Open toolOther Utilities
Epoch Time Converter
Convert Unix timestamps to UTC, IST and readable date-time formats.
Open toolOther Utilities
AS Number Calculator
Convert autonomous system numbers between ASPLAIN and ASDOT notation.
Open toolOther Utilities
JSON Editor
Format, validate, search, edit and export JSON locally in your browser.
Open toolNo matching tools
Try a broader word such as DNS, IP, SSL or port, or choose All Tools.
Learn at your level
Choose your starting point
You do not need to know the tool name. Start with your situation and follow the short path.
I am new to networking
Learn what an address means before testing a live service.
- Use the Subnet Calculator with
192.168.1.10/24. - Open DNS Lookup and see how a name becomes an IP address.
- Try the Ping Checker to test basic reachability.
I am fixing a real issue
Move from the simplest question to the specific service.
- Check the hostname with DNS Lookup.
- Check the route with Ping and Traceroute.
- Check the service with the TCP Port Checker.
I manage websites
Check availability, trust and browser security separately.
- Confirm response and redirects with Website Down Checker.
- Verify trust and expiry with the SSL Checker.
- Review policy with the Security Headers Checker.
Problem-first guide
What are you trying to find out?
Each tool answers a different question. A successful ping does not prove that HTTPS works, and a valid certificate does not prove that the website is online.
“Is the website down?”
Start with Website Down Checker. If it responds, inspect HTTP headers and SSL next.
Check website status“Why does the name not resolve?”
Use DNS Lookup for the record, then DNS Propagation to compare public resolvers.
Inspect DNS records“Why is HTTPS showing a warning?”
Check the live certificate, hostname match, expiry date and certificate chain.
Check the certificate“Where does connectivity fail?”
Use ping for reachability, traceroute for the path and a port check for one service.
Start a connectivity check“Which subnet contains this IP?”
Enter the address and CIDR prefix to see the network, broadcast and usable range.
Calculate a subnet“Who owns or announces this IP?”
Compare IP Location, ASN and WHOIS data. Location is approximate; registry data is authoritative.
Look up the ASNComplete reference
Every tool and when to use it
Use this table when two tools sound similar. The example tells you what to enter; the last column tells you what the result actually means.
Show the complete tool reference29 tools with examples and result explanations
ToolUse it whenExample inputWhat you learn
SSL, certificates and HTTP
SSL CheckerA browser shows a certificate warning or renewal is due.
example.comIssuer, expiry, hostname match, TLS and chain health.Bulk SSL CheckerYou manage many approved domains and need one expiry view.
app.example.comHTTPS status and certificate dates for each hostname.Certificate DecoderYou already have a PEM certificate and need to read it.
-----BEGIN CERTIFICATE-----Subject, SANs, issuer, dates and fingerprints.Chain ComposerA server is missing an intermediate certificate.
server certificate PEMThe correct certificate order and a usable full chain.HTTP Header CheckerYou need status, redirects, caching or cookie details.
https://example.comThe response path and headers returned by the server.HTTP Timing AnalyzerA reachable site is slow and you need to locate the delay stage.
https://example.comDNS, TCP, TLS, TTFB, transfer and redirect timing.CORS TesterA browser application cannot read a cross-origin API response.
API URL + OriginOrigin, preflight, method, header and credential compatibility.Security Headers CheckerYou are reviewing basic browser-side protections.
https://example.comHSTS, CSP, frame, MIME, referrer and permissions coverage.Regex Generator & TesterYou need to match, capture or replace text safely.
\b\d{3}\bMatches, capture groups, replacements and an explanation.IP addressing and public network data
IPv6 Compress & ExpandYou need a readable or fully expanded IPv6 address.
2001:db8::1Valid compressed and eight-group forms.Summary Address CalculatorYou need one IPv4 aggregate for several networks.
172.16.0.0/24 + 3 moreSmallest covering CIDR, bit comparison, and manual commands.Subnet CalculatorYou are planning or checking an IPv4 network range.
192.168.1.10/24Network, broadcast, mask and usable host range.Wildcard Mask FinderYou are writing an ACL or routing network statement.
255.255.255.0The inverse mask and matching address range.IP Location FinderYou need a quick public-IP context check.
8.8.8.8Approximate country, ISP, organization and ASN.ASN LookupYou need to know which network announces an IP.
8.8.8.8ASN, route prefix, registry and network owner.WHOIS LookupYou need registration or allocation information.
example.comPublic registry dates, status and ownership records.IP Blacklist CheckerMail may be rejected because an IP has a bad reputation.
203.0.113.10Whether configured DNS blocklists currently list the IP.AS Number CalculatorYou need to convert between ASPLAIN and ASDOT.
65551Equivalent autonomous-system number notation.Connectivity, DNS and utilities
Ping & Latency CheckerYou need a first public reachability check.
example.comReplies, delay and packet loss from the test server.Traceroute ToolYou need to see where a public path changes or stops.
example.comResponding network hops and timeouts along one route.TCP Port CheckerA specific public TCP service may be blocked or closed.
example.com : 443Whether one authorized TCP port accepts a connection.Website Down CheckerA site does not open and you need an external check.
https://example.comHTTP status, response time, redirects and final URL.DNS LookupYou need the current record for a hostname or domain.
example.com / MXA, AAAA, MX, TXT, NS, SOA or CNAME answers.DNS Propagation CheckerA DNS change works in one place but not another.
example.com / AResolver answers, TTL and consistency across networks.Epoch Time ConverterA log contains a Unix timestamp.
1767225600The matching readable local and UTC date-time.JSON EditorAn API response is hard to read or may be invalid.
{"status":"ok"}Formatted data, syntax errors and a searchable structure.Practice and knowledge checks
Networking Tests HubYou want to choose a topic and measure your baseline.
Choose a subjectA focused practice path with immediate feedback.Routing Practice TestYou are studying OSPF, BGP, EIGRP or RIP.
Answer the quizWeak areas in routing behavior and path selection.Network Security TestYou are revising ACLs, VPNs, AAA and firewalls.
Answer the quizTopics to review before a lab or exam.Read results carefully
A practical four-step troubleshooting method
- Define one question.For example: “Does this hostname return the expected IP?” Avoid testing everything at once.
- Record the input and time.DNS, routes, certificates and reputation data can change. A timestamp makes comparison useful.
- Confirm with a second signal.Compare a public result with a local command, monitoring platform or another network.
- Change only after evidence.A timeout can mean filtering, rate limiting or a distant failure. It does not automatically prove the target is down.
Example: a website will not open
DNS Lookup returns the correct IP, Ping replies, but port 443 is closed. This narrows the problem to the HTTPS service or its firewall path—not DNS and not basic IP reachability.
Common questions
Network tools FAQ
Which tool should I use first?
Start with the symptom. For a website problem, check website status and DNS first. For an address-planning question, use the subnet calculator. For a certificate warning, use the SSL checker.
Why can an online result differ from my laptop?
The tool tests from the Netest server or a public data source. Your laptop may use a VPN, company firewall, private DNS view or different internet route.
Does a failed ping mean the server is down?
No. Many healthy systems block ICMP ping. Check the required application port and website response before reaching a conclusion.
Is IP geolocation exact?
No. IP location is an estimate for the network or service provider. It is not a precise device or home location.
Responsible and permitted use
Use these tools only on systems you own or are authorized to test. Do not submit passwords, private keys, internal-only hostnames or confidential customer data. Public results may be incomplete or stale, so keep raw logs and verify important findings before making a production change.