Best free open port check tools
AdminKit's open-port check scans only the public IP address you are connecting from, against a fixed list of nine high-risk IoT and OT ports, with the restriction enforced server-side; canyouseeme.org, yougetsignal.com, portchecker.co and ping.eu instead let you type in any host and, mostly, any port number, trading that built-in safety limit for far broader arbitrary coverage.
AdminKit is built by Netbase JSC. AdminKit is listed below; the other four tools are independent and not affiliated with AdminKit.
Two different jobs: a curated safety check vs. an arbitrary port scanner
AdminKit’s open-port check scans only the public IP address making the request — determined server-side, the same way the My IP tool reads it — and only after you click to start it, against a fixed list of nine TCP ports device makers commonly leave open by mistake (23 Telnet, 554 RTSP, 1883/8883 MQTT, 502 Modbus, 7547 TR-069, and 80/443/8080 admin web UIs). AdminKit’s Check API itself refuses a scan whose target isn’t the caller’s own IP; there is no field to type in someone else’s address. Several of these protocols appear on CISA’s Known Exploited Vulnerabilities Catalog, read 2026-11-03, when left reachable and unpatched, which is why these nine ports specifically were curated for this check.
The four tools compared here work the opposite way: each one, per its own page, lets you type in any IP address or hostname and (for three of the four) any port number, and runs the check against that target instead of your own connection. That’s a deliberate trade — AdminKit gives up arbitrary-target flexibility in exchange for an abuse-safety property none of the four general tools state they have.
What each tool’s own page says
canyouseeme.org, read 2026-11-03, describes itself as “a free utility for remotely verifying if a port is open or closed,” used to check port forwarding or whether a firewall/ISP is blocking a port. Its form checks one port per submission (a single “Port to Check” field, defaulting to port 80) against your own detected IP — the address field itself is a hidden, pre-filled value, not something you can type over, so like AdminKit it is restricted to your own connection, just one port at a time instead of a fixed curated set.
yougetsignal.com’s Open Port Check Tool, read 2026-11-03, states it tests “the state of ports on any IP address or domain using our servers around the world” — an explicit arbitrary-target design, aimed at verifying port forwarding, troubleshooting a server, or confirming a firewall rule from outside your own network.
portchecker.co, read 2026-11-03, is “a simple and free online tool for checking open ports,” defaulting to your own detected IP but, in its own words, letting you “change the IP input field to check for other IP addresses — remote clients and servers as well,” while asking users not to misuse that option. It accepts any port from 1 to 65535, with preset buttons for common services (FTP, SSH, HTTP and similar).
ping.eu’s port check, read 2026-11-03, states plainly it “tests if TCP port is opened on specified IP.” It’s part of a wider free network-tools page (ping, traceroute, DNS lookup, WHOIS and others) and requires solving a short CAPTCHA code before each check — the only one of the four with that extra step on its own page.
The honest angle
This isn’t a ranking of which tool is “best” overall — the five tools here don’t do the same job. If what you need is “did I just forward this one port correctly on my router” or “is my ISP blocking port 25,” any of the four general tools above will check an arbitrary host and port, something AdminKit’s check does not do and isn’t trying to. If what you need is a one-click look at whether your own internet connection is exposing any of the specific IoT/OT/admin ports that attackers actively target — without having to know which port to ask about, and without a way to accidentally (or deliberately) point the check at someone else’s address — that’s what AdminKit’s port check is for.
AdminKit’s narrower scope shows up in the per-port detail guides it links to once a scan runs: why Telnet and RTSP admin ports end up exposed, is port 23 (Telnet) exposed?, and similar pages for each of the other eight ports, none of which the four general tools’ own pages mention providing. None of them test UDP-based protocols either — AdminKit’s check doesn’t yet cover BACnet/IP or CoAP, and this comparison found no statement either way for yougetsignal.com or portchecker.co, so that point is marked unverified rather than assumed.
If an exposed MQTT broker or Modbus device turns up through any of these checks on a factory or building-automation asset, that’s exactly what AdminKit’s OT Remote Access is built to move behind a VPN/zero-trust tunnel instead of leaving reachable directly from the internet.
Trademarks belong to their respective owners; AdminKit is not affiliated with canyouseeme.org, yougetsignal.com, portchecker.co or ping.eu.
| Feature | AdminKit | canyouseeme.org | yougetsignal.com | portchecker.co | ping.eu |
|---|---|---|---|---|---|
| Scans only the IP address you're connecting from — no field to type in a different host | ✓ | ✓ | ✗ | ✗ | ✗ |
| Checks a fixed, curated list of high-risk IoT/OT/admin ports in one click — no port number to type | ✓ | ✗ | ✗ | ✗ | ✗ |
| Lets you check an arbitrary custom port number of your choice | Fixed 9-port list only, by design | ✓ | ✓ | ✓ | — |
| Free, no account required | ✓ | ✓ | ✓ | ✓ | ✓ |
| Requires solving a CAPTCHA before each check | ✗ | — | — | — | ✓ |
| Explains what an open result on this specific port means, with a link to fix guidance | ✓ | — | — | — | — |
AdminKit vs canyouseeme.org
Checks a fixed, curated list of high-risk IoT/OT/admin ports in one click — no port number to type
Lets you check an arbitrary custom port number of your choice
Requires solving a CAPTCHA before each check
Explains what an open result on this specific port means, with a link to fix guidance
AdminKit vs yougetsignal.com
Scans only the IP address you're connecting from — no field to type in a different host
Checks a fixed, curated list of high-risk IoT/OT/admin ports in one click — no port number to type
Lets you check an arbitrary custom port number of your choice
Requires solving a CAPTCHA before each check
Explains what an open result on this specific port means, with a link to fix guidance
AdminKit vs portchecker.co
Scans only the IP address you're connecting from — no field to type in a different host
Checks a fixed, curated list of high-risk IoT/OT/admin ports in one click — no port number to type
Lets you check an arbitrary custom port number of your choice
Requires solving a CAPTCHA before each check
Explains what an open result on this specific port means, with a link to fix guidance
AdminKit vs ping.eu
Scans only the IP address you're connecting from — no field to type in a different host
Checks a fixed, curated list of high-risk IoT/OT/admin ports in one click — no port number to type
Lets you check an arbitrary custom port number of your choice
Requires solving a CAPTCHA before each check
Explains what an open result on this specific port means, with a link to fix guidance
Frequently asked questions
Does AdminKit's port check let me scan someone else's IP, like these other tools?
No, by design. AdminKit's Check API itself refuses a `ports` scan whose target isn't the IP address the request came from — there is no field to type in a different host. canyouseeme.org works the same way (its port-check form only ever uses your own detected IP, with no editable address field); yougetsignal.com, portchecker.co and ping.eu all let you type in any IP address or domain, per their own pages.
Why does AdminKit only check 9 ports instead of letting me pick any port, 1-65535, like portchecker.co?
It's a deliberate scope limit, not a missing feature. AdminKit's list curates the TCP ports most often left open by mistake on routers, cameras, NAS boxes and small-office IoT/OT gear — several of which appear on CISA's Known Exploited Vulnerabilities Catalog when reachable and unpatched — and interprets what an open result on each one means. A general scanner that accepts any port number is more flexible for ad-hoc troubleshooting (checking a game server port or a custom app), but doesn't curate or explain risk the way AdminKit's fixed list does.
Do canyouseeme.org, yougetsignal.com, portchecker.co and ping.eu test UDP ports as well as TCP?
Unverified for two of them. ping.eu's own page states plainly it "tests if TCP port is opened," and canyouseeme.org's own copy only ever refers to TCP-style services (FTP, SSH, HTTP, RDP); neither page mentions UDP. yougetsignal.com's and portchecker.co's own pages don't state which transport protocol they test at all, so this comparison marks that point as unverified rather than assuming either way. AdminKit's port check is TCP-only today, stated plainly on its own tool page.
Is this page ranking these tools from best to worst?
No. The four general tools and AdminKit's check solve different problems — pick any arbitrary host/port versus a curated, consent-scoped IoT/OT exposure check — so a single best-to-worst order would misrepresent what each one is for. The table below states what each tool's own page confirms, so you can match the tool to your actual need.
I need to check a port on a server I own that isn't my own public IP, like a VPS. Can AdminKit do that?
Not today — AdminKit's port check only ever scans the IP address making the request. For a port on a different host you control, one of the general tools in this comparison (or a manual check with `nc`, as described on AdminKit's own port-check page) is the right tool, since none of them restrict the target the way AdminKit's does.
Does this page use canyouseeme.org's, yougetsignal.com's, portchecker.co's or ping.eu's logo or brand assets?
No. All four names are used only to identify and compare publicly available services (nominative use). AdminKit is not affiliated with or endorsed by canyouseeme.org, yougetsignal.com, portchecker.co or ping.eu.
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