# Proxy without a scheme: HTTP or SOCKS5?

> Nothing in host:port:user:pass says HTTP or SOCKS5, and curl assumes HTTP. At CatProxies we asked the port: 11000 answered SOCKS5, 10000 HTTP.

Source: https://mosaicbrowser.com/blog/port-number-names-protocol

## The port number told us whether a proxy was SOCKS5

Nothing in host:port:user:pass says HTTP or SOCKS5, and curl assumes HTTP. At CatProxies we asked the port: 11000 answered SOCKS5, 10000 HTTP.

![Port 11000 is SOCKS5. The line never says so., beside a screenshot: bulk-importing proxies into Mosaic: every line read, new and duplicate ones told apart](https://mosaicbrowser.com/covers/port-number-names-protocol.webp)

A proxy written as `host:port:user:pass` has no scheme, so nothing in the line says whether it is HTTP or SOCKS5. Some program has to decide. curl decides HTTP. For CatProxies we found the answer sits in the port number: 9000, 10000 and 12000 answer HTTP and 11000 answers SOCKS5. So when Mosaic reads one of those lines, it takes the protocol from the port.

## Why a missing scheme matters

The two protocols open differently. A SOCKS5 server waits for a greeting that starts with the byte `0x05`. An HTTP proxy waits for text: `CONNECT example.com:443 HTTP/1.1` and a `Proxy-Authorization` header. Send one to the other and the server either closes the connection or answers with something the client cannot read.

A full proxy URL settles it, `socks5://user:pass@host:port` or `http://user:pass@host:port`. The four-part colon format most dashboards print does not. It carries a host, a port and two credentials, and the protocol is left to whatever program reads it. curl treats a scheme-less `-x` as HTTP. Our bulk import has a type picker for the same reason: when a line does not say, the import uses the type you chose.

## What went wrong without the port

A batch of CatProxies lines pasted under the wrong type does not fail at import. Every line parses: host, port, username and password are all there and all valid. The proxy is saved as HTTP, the profile is saved with it, and nothing complains.

It fails at launch, one profile at a time. Mosaic checks a proxy before it opens a browser behind it, and our local relay talks to the upstream in the protocol the proxy was saved with. A `CONNECT` sent to a SOCKS5 port gets no reply it can read, so the check fails and the launch stops with a reason. That is the right outcome for one profile. For forty profiles made from one paste, it is forty separate refusals for a mistake made once, in the import.

Mosaic is a desktop app

Email yourself the link and open it on your computer.

[How it works: Bulk proxy import and assign](https://mosaicbrowser.com/features/proxy-import)

## What the gateway told us

We did not take the port map from documentation. We asked the gateway, on one account, port by port, with and without a session token in the username:

```
9000  + -session-          400 "Can not use -session- on rotating ports"
9000  no session           exits PA, then AZ on the next connection
10000 + -session-ab12cd34  97.238.70.34, and 97.238.70.34 again
10000 + -session-zz99yy11  152.13.118.218, a different id, a different exit
11000 + -session-          SOCKS5 authentication failed
11000 no session           exits PH, then US on the next connection
12000 anything             no answer at all on this account

```

That is two facts per port. The protocol: 11000 is SOCKS5, the rest are HTTP. And stickiness: 9000 hands out a new exit on every connection and refuses a session token outright, while 10000 holds one exit per session id. We keep 12000 in the table although it answered nothing on that account, because it appears in issued endpoints, and an account that has not bought that product is no evidence the port is retired.

## What Mosaic does with it

When a pasted CatProxies line has no scheme, the parser looks the port up in that table and stores the protocol the gateway uses. An explicit `socks5://` or `http://` in the line still wins, because then the person pasting has told us. The same table drives the editor: switching a CatProxies proxy to a sticky exit moves it to a sticky port, rather than saving a session token on 9000 that would fail with that 400 at every start.

We read the port only where we have measured it. For every other seller, a line without a scheme takes the type picked for the import, or a `type` or `protocol` column if the list is a table with a header row. Guessing from a port number nobody has tested would be the same mistake in a new place. Ports are the seller's choice, and the same number means HTTP at one gateway and SOCKS5 at another.

![Bulk proxy import in Mosaic: every line read, new and duplicate ones told apart](https://mosaicbrowser.com/shots/proxy-import.png)
*Bulk import, where a line without a scheme takes the type you choose*

## How to tell for a line you already have

If the seller's dashboard names the protocol next to each port, believe the dashboard. If it does not, test the line twice with curl, changing only the scheme:

```
curl -x http://user:pass@host:port https://api.ipify.org
curl -x socks5h://user:pass@host:port https://api.ipify.org

```

The one that prints an address is the protocol. `socks5h` makes the proxy resolve the site's name, which is what you want from a proxy that is supposed to be somewhere else.

Then write the scheme into the line before you paste it anywhere, and it stops depending on which program reads it. Our [proxy list formatter](https://mosaicbrowser.com/tools/proxy-list-formatter) converts a colon list into URLs in one go, and the [proxy checker](https://mosaicbrowser.com/tools/proxy-checker) tells you whether each one answers and where it exits. Mosaic's own import, with its four ways of dealing a list out across profiles, is on the [bulk proxy import](https://mosaicbrowser.com/features/proxy-import) page. Why each profile needs its own working proxy at all is covered in [what an anti-detect browser is](https://mosaicbrowser.com/guides/what-is-an-anti-detect-browser).

## Questions

### How do I know if a proxy is HTTP or SOCKS5 when the line has no scheme?

Look at the seller's dashboard, which usually names the protocol per port, or test it: run curl once with -x http:// and once with -x socks5h:// in front of the same host, port and credentials, and keep the one that returns a page.

### What happens if a SOCKS5 proxy is saved as HTTP?

It fails when it is used, not when it is saved. The browser speaks HTTP to a server waiting for a SOCKS5 greeting, the connection dies, and every profile carrying that proxy fails on its own when it launches.

### What does curl assume when a proxy has no scheme?

curl treats a proxy given to -x without a scheme as an HTTP proxy. Other tools have their own defaults, which is why a bare host:port:user:pass line means different things in different programs.

### Does Mosaic guess the protocol for every seller?

No. It reads the port only for a gateway whose ports it has measured, which is CatProxies. Any other line without a scheme takes the type you picked for the import, a type column in a table, or the scheme written in the line itself.

## Related

[What is an anti-detect browser?](https://mosaicbrowser.com/guides/what-is-an-anti-detect-browser): An anti-detect browser gives each profile its own fingerprint, proxy and cookies, so sites see separate visitors. What it changes, how, and its limits.

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## Mosaic, on your own computer

The browser this blog is about: its own Chromium, fingerprints from real machines and a proxy exit per profile. Free holds 3 profiles. Pro is $49 a month for any number.

Mosaic is a desktop app

Email yourself the link and open it on your computer.