1
Username:password
- How the proxy identifies you
Proxy-Authorizationheader or SOCKS5 login- Best for
- Laptops, cloud jobs, any changing source IP
- Watch out for
- Special characters must be URL-encoded in proxy URLs
G2
4.7/5Excellent
Trustpilot
TrustpilotWhat Is Proxy Authentication?
Proxy authentication is how a proxy server checks that a connection belongs to a customer before forwarding it. The two common methods are a username and password sent in the Proxy-Authorization header, and IP whitelisting, where the proxy accepts connections only from registered addresses.
- Session Control
- High Speed
- Privacy First
how it works
How proxy authentication works
HTTP defines a challenge and response for proxies in RFC 9110. When a request arrives without valid credentials, the proxy answers 407 Proxy Authentication Required with a Proxy-Authenticate header naming the scheme it accepts, usually Basic. The client then repeats the request with a Proxy-Authorization header.
Under the Basic scheme (RFC 7617), the header value is Basic followed by the Base64 encoding of username:password. Base64 is an encoding, not encryption. Most clients send the header up front when the proxy URL contains credentials, so the 407 round trip only appears when something is wrong. SOCKS5 has its own username and password exchange during the handshake, so the same credentials work there without any HTTP header.
IP whitelisting
- How the proxy identifies you
- The source IP of the connection
- Best for
- Fixed servers and tools that cannot send proxy credentials
- Watch out for
- Stops working when your public IP changes
- 3
Gateway username options
- How the proxy identifies you
- The username also carries settings such as country or session
- Best for
- Rotating residential and mobile pools
- Watch out for
- The format is provider-specific
why it matters
Why the method matters for proxy users
The method you choose decides what can break. Credentials travel with every connection, so they work from any machine but leak if you paste proxy URLs into logs or shared scripts. Whitelisting keeps secrets out of your code but ties access to an address you may not control, such as a home connection with a dynamic IP or behind CGNAT.
CleanProxies static ISP proxies support username:password over HTTP(S), IP whitelisting of 1 to 20 IPv4 addresses, or SOCKS5 with the same username and password; rotating residential and mobile proxies use username:password only.
Proxy authentication: what it means for you
- If a proxy works in curl but not in your app, compare how each sends credentials. Some tools cannot send
Proxy-Authorizationat all and need IP whitelisting. - Repeated 407 responses mean the proxy is rejecting your credentials or your source IP; see 407 Proxy Authentication Required.
- Keep credentials in environment variables or a secrets store, not in committed code.
Static ISP proxies from $0.75/IP
The CleanProxies proxy that fits best here, with a $4.99 trial to test it first.
Best fit
Dedicated IPs on US carrier ASNs with unlimited bandwidth and threads, never shared.
starting from$0.75/IP
Dedicated static IPs registered to US and Canadian ISPs. The address stays the same for as long as you hold it, with unlimited bandwidth and HTTP(S) or SOCKS5 access.
Guides from the blog
Setup guides and best practices from the CleanProxies blog.
- GuidesOct 30, 2026
Shared vs Dedicated ISP Proxies: Differences, Risks and a Free Audit Script
Shared vs dedicated ISP proxies explained: what each model means, what providers publish about sharing, when shared is enough, cost per successful request, and a tested Python script to audit your proxy list.
19 Min ReadRead article - GuidesOct 27, 2026
How to Test Proxy Quality: Fraud Score, Blacklists, Speed and Leaks
A step-by-step guide to testing proxy quality before you use it: connectivity, exit IP, ASN, blacklists, fraud score, speed and WebRTC/DNS leaks, with free tools, cURL commands and what good results look like.
13 Min ReadRead article - GuidesNov 1, 2026
Best Oxylabs Alternatives in 2026: 6 Providers Compared
Oxylabs' best rates need a $2,500/month enterprise plan. We priced five workloads on Oxylabs and five alternatives on 1 November 2026, with screenshots. CleanProxies ranks #1: dedicated US ISP proxies as low as $0.75/IP, residential from $0.63/GB that never expires.
21 Min ReadRead article - GuidesNov 1, 2026
Best Smartproxy (Decodo) Alternatives in 2026: 6 Providers Compared
Smartproxy is now Decodo. We priced the same workloads on Decodo and six alternatives on 1 November 2026, with screenshots. CleanProxies ranks #1: residential as low as $0.63/GB that never expires, US ISP proxies as low as $0.75/IP, mobile from $0.79/GB.
20 Min ReadRead article - GuidesOct 31, 2026
Best IPRoyal Alternatives in 2026: 6 Providers Compared (Prices Checked)
The best IPRoyal alternatives in 2026, compared on prices read from each provider's pricing page on 31 October with screenshots. CleanProxies ranks #1: residential as low as $0.63/GB that never expires, US ISP proxies as low as $0.75/IP with unlimited bandwidth, mobile from $0.79/GB.
16 Min ReadRead article - GuidesOct 31, 2026
How Many IPs Are in a /24 Subnet? (256 Addresses, Explained)
A /24 subnet has 256 IPv4 addresses: 254 usable on a LAN, 251 in AWS or Azure, and 255 dedicated proxy IPs per block at CleanProxies. CIDR cheat sheet, Python examples and a tested script that audits your proxy list by /24.
19 Min ReadRead article
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Related terms
Terms that come up alongside Proxy authentication.
Proxy authentication FAQs
Straight answers about Proxy authentication.
The password is only Base64-encoded, so anyone who can read the connection between you and the proxy can read it. For https:// sites the website traffic is still encrypted inside the tunnel; only the proxy credentials are exposed on that hop.
Got more questions?All FAQs