NET INSIGHT · NETWORK DIAGNOSTICS
See what your network is saying.
Find your public IP, inspect its network signals and compare DNS answers from independent resolvers. Real data, with its limits shown.
- IPv4 & IPv6
- Sources & timestamps
- Exportable results
DIAGNOSTICS
Pick a check.
Address
7- 01
What Is My IP Address? See the Address This Site Sees
Your public IP address, its network owner and its approximate location, looked up automatically as the page loads and shown with its source and query time.
Open → - 02
IP Purity Check: The Signals, and the Rule Behind Each One
See which observations an address carries, what each one can and cannot prove, and the published rule that produced every line of the result. No composite score.
Open → - 03
IP Reputation Check: Compare the Sources Instead of Trusting One
Check an address and see which reputation provider produced each observation, why the providers disagree, and what a provider's own risk number actually represents.
Open → - 04
IP Blacklist Check: Which List, Why, and How It Comes Off
Blocklists are separate organisations, not one database. See which lists exist, what each records, the published removal route, and how to read an abuse signal.
Open → - 05
ASN Lookup: Whose Network Is This Address On?
Look up an address and read its autonomous system, the organisation that announces it, and what the ownership actually tells you about a website or a mail server.
Open → - 06
IPv6 Test: Which Address Family Your Connection Actually Used
See whether this connection arrived over IPv4 or IPv6, whether the device holds a global IPv6 address, and what each of those two observations does and does not prove.
Open → - 07
NAT Type Check: What Your Router Does to Outbound Connections
Run a local STUN probe to see the public address your router presents, whether translation is happening at all, and when the result should honestly say not measurable.
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DNS
5- 01
DNS Resolver Comparison
Compare A, AAAA, MX, TXT and other DNS answers from Cloudflare and Google, including TTL and DNSSEC status.
Open → - 02
DNS Propagation Checker: What Two Resolvers Answer Right Now
Compare Cloudflare and Google for the same name, see where they differ, read the TTL that decides your wait, and compare against the previous run on this device.
Open → - 03
Reverse DNS Lookup: PTR Records and Forward-Confirmed Names
Look up the PTR record for an address, check whether the name it claims resolves back to the same address, and see why that pair matters for mail.
Open → - 04
WHOIS Lookup Alternative: What the DNS Reveals About a Domain
Read the naming servers, zone contact and SOA serial a domain must publish, understand why registration records come back redacted, and open the registry lookup that holds them.
Open → - 05
DNS TTL Explained, With a Calculator for the Wait After a Change
Work out the longest time a cached answer can still be served after a DNS change, and read why lowering the TTL afterwards does not shorten a wait that has already started.
Open →
- 01
SPF Record Checker: Inspect Top-Level DNS Terms
Read the top-level SPF formula and default result. Compare DNS observations; recursive include limits and real sending-IP authentication are not evaluated.
Open → - 02
DMARC Record Checker: Live DNS Lookup and Tag Inspector
Check the TXT record at _dmarc, compare resolver evidence or inspect a pasted record. Read current DMARC tags without claiming an inbox delivery result.
Open → - 03
DKIM Checker: Probe the Selectors and Size the Published Keys
Try the selectors senders use most often, read the key each one publishes, and understand why a private selector is indistinguishable from no DKIM at all.
Open → - 04
MX Record Check: Where Mail Goes and What Fails First
List the mail exchangers for a domain with their preferences, spot the single point of failure, and check the host senders try first for the alias and reverse-record rules.
Open → - 05
Email Deliverability Test: Mail DNS Preflight and Limits
Inspect MX, top-level SPF, exact-name DMARC and common DKIM selectors. Keep failed lookups unknown and choose a next step from real message evidence.
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TLS
2- 01
CAA Record Checker & DNSSEC Record Lookup
Look up CAA, DS and DNSKEY records. Separate empty answers from resolver failures, and calculate a certificate validity window from dates you paste.
Open → - 02
HTTP Header Check: Paste a Response and Audit It Offline
Paste a response block and get a header-by-header audit covering transport security, framing, referrer leakage, cookie flags and version disclosure — parsed locally.
Open →
HOW IT WORKS
What each result does and does not prove.
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A Practical Network Diagnostics Guide
Separate DNS resolution, IP ownership and website reachability before deciding what is broken, with the checks to run in the order that avoids chasing the wrong layer.
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How to Get Off an Email Blacklist, and How to Know If You Are On One
Find out whether a sending address is listed, understand that delisting is only half the job, and follow the order that stops the same address being relisted.
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VPN and Proxy Detection Explained: What the Signals Really Show
How providers infer that an address belongs to a VPN, a data centre or a proxy, why their answers disagree, and why a flag is an observation rather than a fact about a person.
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IP Reputation Guide: Why There Is No Single Score
How reputation data about an address is produced, why providers disagree, what each type of observation does and does not support, and why a clean result is not a pass.
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DNS Record Types Explained, and Which Ones You Can Ignore
A working reference to A, AAAA, CNAME, MX, TXT, NS, SOA, CAA, DS and DNSKEY records: what each one does, what it cannot prove, and when it matters.
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Why Legitimate Email Goes to Spam, and What Actually Changes It
Separate the four things that decide where your mail lands — authentication, reputation, engagement and content — and find out which ones you can change and which you cannot.
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DMARC Policy Guide: Review Alignment Before Tightening Policy
A staged rollout from p=none to p=reject: what each state does, how to read aggregate reports, why alignment is the part that breaks, and the checks to run before tightening.
Pages on this site
Update and accuracy policy
Each page here answers one diagnostic question and shows the evidence behind the answer: which resolver was asked, when it answered, and what the result does not prove. Where a third-party database is involved, its limitation is stated on the same page rather than left implicit.
Diagnostic results are timestamped; guidance is dated. A page describing a check is revised when a source changes its behaviour or its data, and superseded text is removed rather than left standing next to the new version. If a result here disagrees with your own tooling, the contact form reaches a person.