Proxy Usage Limits

A large IP list does not necessarily provide a large allowance for simultaneous work. The limit may belong to the whole account, a package, an individual IP, or a particular endpoint. The scope determines whether different programs are sharing the same capacity.

Suppose an account allows 500 open connections. Three programs opening 200 each would require 600. Assigning a different proxy IP to each program does not increase that account-wide allowance. A per-IP limit works differently: distributing the workload can make use of capacity on several addresses, subject to any additional shared limit.

The software's worker count is also a poor substitute for the provider's connection count. One browser profile can contact a store, its image servers, and its login service through several connections. One application thread can run many requests asynchronously. Connections may stay open for reuse, while HTTP/2 can carry multiple requests through one connection.

This explains a familiar result: a few test pages load correctly, but launching the full set of browser profiles produces failures. A slower target can add to the pressure by keeping connections occupied longer. The useful allowance is the one that covers the combined workload, including other programs using the same account.

An IP can be fully operational while the provider refuses to connect it to a particular site. Destination restrictions can apply to a hostname, an address range, a category of services, or an operation such as signing in. Financial services, government resources, ticketing platforms, and webmail appear in published restrictions, although the actual list depends on the product.

Changing every IP in a package can leave this problem untouched. If the rule belongs to the account or network, each replacement encounters the same refusal. The request may be stopped before the target website receives it.

Apps make the boundary less obvious. A shop's home page can open while its sign-in or checkout fails because those functions use different hosts. A messaging app can load its interface but lose a connection needed for live updates. One accessible domain does not establish that every part of the app is available.

The target website can independently reject a proxy visitor or show a CAPTCHA. That is a different restriction, controlled by the website. Permission from the proxy provider settles whether its service will carry the request; it does not guarantee that the destination will accept it. Where exceptions are offered, approval can also be specific to a product, account, and intended task.

The port used to connect to a proxy is different from the port the proxy is asked to reach. In proxy.example:1080, 1080 is the proxy entry port. Through that same entry point, software can request shop.example:443 or mail.example:587. The provider can allow the first destination and refuse the second.

This distinction explains why a mailbox can work in a browser while a mail application cannot send through the proxy. Webmail commonly uses HTTPS on TCP 443. Direct mail submission can use SMTP on TCP 587 or 465, while port 25 is used for SMTP relay between mail servers. Commercial proxy services commonly restrict outbound SMTP to prevent spam and protect their IP addresses from sender blocklists. The webmail domain can have its own access restriction as well.

Other affected services can include SSH on port 22, RDP on 3389, databases, and websites on alternative ports such as 8080 or 8443. Some products block selected ports; others allow only a specified list. A legitimate task can therefore fall outside what a web-focused proxy product supports.

A SOCKS5 label does not promise unrestricted ports or UDP support. Likewise, working HTTPS over TCP 443 does not establish that UDP 443 is available. Changing the proxy's entry port changes where the client connects to the provider; it does not rewrite the requested destination port.

Which product and account the limit belongs to

The same seller can offer different permissions and capacity across datacenter, ISP, residential, and mobile products. A free sample, a paid package, and a managed scraping service can also differ. A successful test with one product does not establish the permissions of another.

The words used to sell a plan answer different questions. Dedicated describes the allocation of an address. Unlimited traffic concerns consumption or billing. SOCKS5 identifies a proxy protocol. None of these labels, by itself, specifies the connection allowance or the complete list of permitted destinations.

Some restrictions apply from activation; others appear later. For example, a fair-use rule can reduce concurrency after heavy traffic consumption. An account allowlist can restrict destinations more narrowly than the product's default settings. These changes can make a previously successful workload fail while the IPs remain reachable.

The practical question behind an upgrade is which allowance changes. More IPs can help distribute work under a per-IP connection cap. They do not automatically increase an account-wide cap, authorize a restricted website, or open an outbound port.

Who refused the request matters

A provider message identifying a connection limit, prohibited destination, or blocked port is more informative than a general failure code. HTTP 403, 429, 502, a reset, or a timeout can have more than one cause. The application's own connection pool, the proxy service, an upstream network, and the target website can each stop or delay work.

There is therefore a difference between “the proxy could not connect,” “the provider refused this connection,” and “the website rejected the visitor.” Replacing IPs, adding browser workers, or buying a larger package can leave the problem unchanged when the change does not address the actual restriction.

What a successful test actually proves

Opening an IP-check page establishes something about that particular connection. It does not test every destination, every app function, or the workload planned for production. A checker that uses a restricted destination can also report working IPs as unavailable.

A useful result matches the intended job: the same product and account permissions, the required websites and services, and enough simultaneous activity to represent the workload. Even an HTTP 200 response needs context if it contains a challenge page instead of the requested content.

The three detailed articles let the reader separate these questions. Connection limits explain available parallel capacity. Website and app restrictions explain which destinations and operations are permitted. Port restrictions explain which network services the proxy can reach. Together, they describe what a working proxy package actually allows its customer to do.