Free Online Proxy Checker: HTTP, HTTPS, SOCKS4, SOCKS5 - With Real SOCKS5 UDP Testing
Most proxy checkers only tell you whether a proxy responds to a TCP connection. That is not enough. If you rely on SOCKS5 proxies for applications that need UDP - gaming, VoIP, torrenting, DNS - a proxy that "works" on a basic check can still silently fail your traffic. Localtonet's free proxy checker goes further: it tests actual UDP send/receive capability on SOCKS5 proxies, shows you exit IP and geolocation, measures latency, and checks HTTPS support - all in your browser, in parallel, in under 30 seconds.
What Is the Localtonet Proxy Checker?
The Localtonet Proxy Checker is a free, browser-based tool that validates proxy lists in bulk. Paste up to 50 proxies, in any supported format click Start Check, and within seconds you get a detailed results table showing connectivity status, protocol type, anonymity level, response time in milliseconds, real exit IP address, country flag, HTTPS support, UDP capability, and whether authentication is required.
Unlike simple ping-based checkers, Localtonet performs real protocol-level handshakes. For SOCKS5 proxies specifically, it goes beyond a TCP CONNECT test and actually attempts a SOCKS5 UDP ASSOCIATE handshake followed by real UDP packet send/receive. This is the only way to verify whether a SOCKS5 proxy genuinely supports UDP - a capability that matters enormously for gaming, DNS, WebRTC, and any application that is not purely TCP-based.
Why SOCKS5 UDP Support Actually Matters
SOCKS5 is the most capable proxy protocol available. Unlike HTTP proxies (which only handle HTTP/HTTPS traffic) and SOCKS4 (which only supports TCP), SOCKS5 supports both TCP and UDP connections, plus authentication. This makes SOCKS5 the right choice for applications that need to proxy any kind of network traffic.
The catch: supporting SOCKS5 and supporting SOCKS5 UDP are not the same thing. Many SOCKS5 proxy servers only implement the TCP CONNECT command and silently drop or reject UDP ASSOCIATE requests. If your application sends a UDP ASSOCIATE command to one of these proxies, one of two things happens:
| What the checker shows | What it means | UDP applications work? |
|---|---|---|
| UDP ✓ RT | Full SOCKS5 UDP support confirmed. The proxy accepted a UDP ASSOCIATE command, the checker sent real UDP packets, and received a response (round-trip). | ✅ Yes - DNS, gaming, VoIP, torrenting, WebRTC all work |
| UDP ✓ (no RT) | The proxy accepted the UDP ASSOCIATE command and returned a relay address, but no round-trip UDP response was confirmed. Partial UDP support. | ⚠️ Maybe - command accepted but full flow not verified |
| TCP only | The proxy is SOCKS5 but only supports TCP CONNECT. UDP ASSOCIATE was rejected or timed out. | ❌ No - UDP traffic will fail silently or error |
| No UDP | SOCKS4 proxy (UDP not part of the protocol) or HTTP proxy. | ❌ No - protocol does not support UDP at all |
A TCP-only check against a SOCKS5 proxy will show it as "working" even if UDP is completely broken. The checker connects, completes a TCP handshake, and marks the proxy online. Your application then uses UDP through that proxy, the packets are dropped, and you have no idea why. Localtonet's checker actually sends UDP data and waits for the return packet. A proxy marked UDP ✓ RT has proven real bidirectional UDP capability - not just an accepted handshake command.
Supported Proxy Input Formats
The proxy checker accepts up to 50 proxies per check, one per line. All common proxy list formats are supported, and you can mix formats in the same list:
# Basic (no authentication)
host:port
192.168.1.1:1080
# With credentials - colon-separated
host:port:user:pass
192.168.1.1:1080:myuser:mypassword
# With credentials - @ format
user:pass@host:port
myuser:mypassword@192.168.1.1:1080
# URL format - HTTP
http://user:pass@host:port
http://myuser:mypassword@192.168.1.1:8080
# URL format - SOCKS5
socks5://user:pass@host:port
socks5://myuser:mypassword@192.168.1.1:1080
# You can also import from a URL (raw text file)
# Click "Import from URL" and paste a direct link to your proxy listThe protocol type (HTTP, SOCKS4, SOCKS5) is auto-detected from the format. If you paste a plain host:port without a protocol prefix, the checker tries all supported protocols and reports whichever one responds. You can also use the sample buttons to populate the input with example HTTP or SOCKS5 proxies to see how the tool works before testing your own list.
How to Use the Proxy Checker - Step by Step
Open the tool
Go to localtonet.com/tools/proxy-check. No account or login required for basic usage.
Paste your proxy list
Paste up to 50 proxies into the input box on the left, one per line. Any supported format works - mix HTTP, SOCKS4, and SOCKS5 in the same list. The counter shows how many proxies are loaded (e.g. 43 / 50). Alternatively, click Import from URL and paste a direct link to a raw proxy list file.
Click Start Check
The checker runs all proxies in parallel. The Session panel on the left shows live progress: Status (Running → Completed), Mode (Parallel), Protocol (AUTO), and elapsed time. Results appear in the table in real-time as each proxy is checked.
Read the results table
Each row shows: Address, Type (HTTP/SOCKS4/SOCKS5), Status (OK/FAIL), Anonymity, response time in milliseconds, Exit IP, country flag, HTTPS support, UDP support, and Login (whether authentication was used). Sort any column by clicking the header.
Filter and export
Use the dropdown filters at the top - All types, All status, All countries - to narrow down results. Then click Export Working Proxies to download a clean list of only the proxies that passed. Multiple export format options are available from the dropdown arrow.
Understanding the Results Table
| Column | What it shows | What to look for |
|---|---|---|
| Address | The proxy IP address and port | As entered in your list |
| Type | Protocol detected: HTTP, SOCKS4, SOCKS5 | SOCKS5 is most capable. SOCKS4 for TCP-only. HTTP for web traffic only. |
| Status | Green OK = proxy responded and passed checks. Red FAIL = timed out or rejected connection. | Only OK proxies are functional. FAIL proxies are dead, offline, or blocking the check source. |
| Anonymity | Elite = your real IP is hidden, no proxy headers forwarded. Anonymous = IP hidden but proxy headers present. Transparent = your real IP is visible to target servers. | Elite for maximum privacy. Transparent proxies provide routing only, no anonymity. |
| MS | Round-trip latency in milliseconds | Under 100ms is fast. 100-500ms is acceptable. Over 500ms will feel sluggish for browsing. 0ms means the check did not complete a meaningful timing measurement. |
| Exit IP | The actual IP address that destination servers see when traffic exits through this proxy | Should differ from the proxy address for properly configured proxies. Shows the real geographic origin of outbound traffic. |
| GEO | Country flag and name for the exit IP | Use the country filter to export only proxies from specific regions for geo-targeting use cases. |
| HTTPS | HTTP only = proxy can only handle plain HTTP traffic. HTTPS = proxy supports HTTPS tunneling via CONNECT. | HTTPS support is required for modern web browsing, API calls, and any encrypted traffic. |
| UDP | UDP ✓ RT = full UDP confirmed with real round-trip. UDP ✓ = UDP ASSOCIATE accepted, no round-trip. TCP only = SOCKS5 but UDP rejected. No UDP = protocol does not support UDP. | Require UDP ✓ RT for gaming, DNS, VoIP, and torrenting. TCP only SOCKS5 proxies will silently fail UDP applications. |
| Login | Whether the proxy requires authentication | A dash (–) means no authentication needed. Shows N/A if auth could not be determined. |
HTTP vs SOCKS4 vs SOCKS5: Which Proxy Type Do You Need?
| Protocol | Traffic support | UDP | Authentication | Best for |
|---|---|---|---|---|
| HTTP | HTTP and HTTPS traffic only (via CONNECT tunnel for HTTPS) | No | Basic (user:pass in header) | Web browsing, web scraping, HTTP API calls. Does not work with non-HTTP applications. |
| SOCKS4 | Any TCP traffic | No | Username only (no password) | TCP applications that do not need UDP. Older protocol, limited authentication. |
| SOCKS5 (TCP only) | Any TCP traffic | No (partial implementation) | Full username + password | All TCP applications. Better than SOCKS4 for auth, but UDP will fail despite being SOCKS5. |
| SOCKS5 (UDP ✓ RT) | Any TCP and UDP traffic | Yes - fully tested | Full username + password | Gaming, DNS queries, VoIP, BitTorrent, WebRTC, and any application using UDP transport. |
A very common mistake: you find a SOCKS5 proxy list, verify the proxies are "online," configure your application to use SOCKS5, and then experience random failures or connection drops. The proxies are alive - but they only handle TCP, and your application's UDP traffic is being silently dropped. The Localtonet checker's UDP column tells you immediately which SOCKS5 proxies have full UDP support and which are TCP-only, so you can match the proxy to your application's actual requirements.
Common Use Cases for Proxy Checking
Frequently Asked Questions
What is the difference between "UDP ✓ RT" and "UDP ✓" in the results?
UDP ✓ RT means the proxy completed a full real-world UDP round-trip: the checker sent the UDP ASSOCIATE command, the proxy accepted it and returned a relay address, the checker sent actual UDP packets to that relay, and received response packets back. This is the strongest possible confirmation of UDP support - the proxy has proven it can carry real UDP traffic in both directions.
UDP ✓ (without RT) means the proxy accepted the UDP ASSOCIATE command and provided a relay endpoint, but the actual UDP packet exchange did not complete a confirmed round-trip. The proxy may still work for UDP in practice, but it could not be fully verified. For reliable UDP applications, prefer proxies marked UDP ✓ RT.
Why does a proxy show OK but still fail in my application?
The most common reason is a UDP mismatch: your application needs UDP, but the proxy is SOCKS5 with only TCP support. The checker marks it OK because TCP connectivity works, but your application's UDP traffic fails. Check the UDP column - if it shows TCP only, the proxy will not work for UDP-dependent applications even though it is technically online.
Other reasons include: the proxy IP-whitelists certain sources (it responds to the checker's IP but blocks your IP), the proxy has bandwidth limits that only appear under sustained traffic, or the application protocol uses features the proxy does not support (such as specific SOCKS5 auth methods).
Does the checker store or log my proxies?
No. Proxies are not stored on Localtonet's servers. Each check is processed in real time and discarded. Credentials in authenticated proxy formats (user:pass) are used only to test connectivity and are never logged or retained. Results are visible only to you during your browser session.
Why do some working proxies show 0ms response time?
A 0ms reading indicates that the latency measurement could not be completed, even though the proxy responded successfully to the protocol-level check. This can happen with proxies that pass authentication but do not send measurable response timing data, or proxies that are behind intermediate relay layers that obscure timing. The proxy is functional - the 0ms is a measurement artifact, not a sign of exceptional speed.
What does "Elite" anonymity mean versus "Anonymous"?
Elite (also called high-anonymous) proxies do not forward any identifying headers to destination servers. The target server sees only the proxy's IP and has no indication that a proxy is involved. Anonymous proxies also hide your real IP, but they include headers such as X-Forwarded-For or Proxy-Connection that reveal a proxy is in use (though not your real IP). Transparent proxies pass your real IP to the destination in headers - they only provide routing, not anonymity. For privacy-sensitive use cases, use Elite proxies.
Can I check more than 50 proxies at once?
The current limit is 50 proxies per check session. For larger proxy pools, split your list into batches of 50 and run multiple checks. The Export Working Proxies function lets you collect results from each batch. Since checking runs in parallel and completes in under 30 seconds for most lists, even a pool of several hundred proxies can be validated in a few minutes using multiple batches.
Check Your Proxies - Free, No Account Required
Paste your proxy list, click Start Check, and get full results in under 30 seconds. HTTP, HTTPS, SOCKS4, SOCKS5 - with real UDP round-trip testing for SOCKS5 proxies. No registration, no data stored.
Check Your Proxies Now →
