Proxy for Garry's Mod: Separating Content Downloads from Game Traffic
Garry's Mod brings two different network models together in a single connection: the UDP-based game traffic that talks to the server, and the HTTP downloads that pull the server's content. A proxy does not treat these two the same way, and the way to get the setup right is to see the distinction from the outset.
Traffic classesServer browser, game traffic, content downloads and voice traffic.
02
Content downloadPulling server content over HTTP, and the Workshop side.
03
UDP limitsWhere SOCKS5 UDP ASSOCIATE support ends in practice.
04
NAT behaviourThe effect of address translation when you host a server from your own machine.
Community servers are at the heart of the Garry's Mod experience. When you join an address from the server browser, the client first establishes a session with the server, then downloads the maps, models and scripts that server uses. These two jobs run over different protocols.
The game session runs on the Source engine's network layer and predominantly carries UDP. Content downloads, on the other hand, run over HTTP: the server administrator publishes the files on a web server and the client pulls them from there. From a proxy's point of view, the second is easy and the first is hard.
This page covers the two sides separately; it then moves on to what address translation does when you host a game from your own machine, and why a proxy is not a solution in that picture.
How many kinds of traffic are there in one connection?
When you open the server browser, the client requests a server list and sends status queries to the addresses on the list. Then a join request goes to the server you select. Once the session is established, position, event and input data flow continuously. In parallel, missing content files are downloaded.
Most of this traffic is UDP. The Source engine's traditional default server port is 27015/UDP, but server administrators can change it and many hosting providers use different port ranges. A port number does not determine the protocol; that distinction itself proxy port numbers is explained separately in the article.
The content download side is classic HTTP and can be carried by a proxy without issue. So in the same session of the same game, one stream may go through the proxy while the other does not. That is exactly the technical explanation for a setup appearing to "half work".
The server list and the server itself are separate addresses
The list in the server browser comes from a list service, not from the individual servers. Once the list is loaded, the client sends its own status queries to the addresses on it; player count, map name and estimated latency are filled in from those queries. So a situation where "the list loads but the servers appear empty" means that only one of two different network jobs is working.
From a proxy's point of view the conclusion is this: reaching the list service may be TCP-based and routable, while status queries go to the servers' own ports. If you can see servers in the list after setup but cannot connect, start your diagnosis at the query layer.
DIAGRAMRoutability of traffic classes
You can scroll the diagram horizontally to inspect it
The columns are not measurements but representative scores showing the likelihood that a proxy rule will cover that class.
The platform client, the game client and updates
Garry's Mod is installed and updated through the platform; while the game itself is running, the platform client sits in the background. This distinction matters for proxies because the two programs do not read network settings the same way. One may honour the system setting while the other opens its own sockets directly.
Version updates and Workshop subscriptions are downloaded by the platform client. These downloads are HTTP and can be brought into the proxy's scope; that does not mean they should be. Because the path is longer, the transfer is usually slower and unnecessary cost arises on a metered plan. Practical notes Steam proxy settings are collected in the article.
In-game content and platform updates should not be confused. The first happens while joining a server, the second when a release comes out. They come from different sources and generate volume at different times; treat them as separate line items when planning quota.
The subscription model has another side effect: when you subscribe to a collection, the content is downloaded in the background without you opening the game. If you are working over a metered exit, that is consumption you did not initiate. Reviewing your subscriptions occasionally makes a difference on both the disk and the quota side.
Tip
If you write a rule that applies the proxy only to the game process, platform updates stay on your normal line. In most setups this is the most balanced approach in terms of both quota and download time.
Downloading server content
Most community servers use their own maps, models and materials. Because transferring these files over the game session is slow, administrators publish the content on a separate web server and direct the client there. The result is an HTTP download session entirely independent of the game traffic.
From a proxy's point of view this is good news: because that download speaks HTTP over TCP, it can be carried by both an HTTP proxy and SOCKS5. CONNECT If you are curious how the method works the HTTP CONNECT method the article shows the mechanism step by step.
The thing to watch out for is volume. Joining a content-heavy server for the first time means a substantial download in one go, and that download is repeated when the server updates its content. If you are using a metered exit, doing the first join outside the proxy is a reasonable choice.
The download address and the game server's address do not have to be the same; in most setups they are separate machines and can be in different countries. This introduces a subtle detail when writing a proxy rule: a rule that covers only the server address leaves the content download out, and a rule that covers only the download domain does not cover the session. Thinking about scope address by address heads off later surprises.
Track content downloads as a separate line item from the game traffic.
Do the first join on an unmetered line and route subsequent sessions.
If a download stalls, first check that the exit is alive, then your remaining quota.
The real limit of carrying UDP over SOCKS5
UDP ASSOCIATEis the path SOCKS5 defines for carrying UDP: the client establishes a TCP control connection with the proxy, the proxy allocates a UDP relay point, and datagrams are carried through that point. The definition is clear; the problem is in the implementation.
Three conditions must be met at once. The proxy server must support this command — many commercial exits offer TCP only. The client must know how to use this path; the vast majority of game clients have no SOCKS5 awareness. Finally, the firewalls in between must pass the datagrams going to the relay point.
The relay point itself also creates a cost. Because datagrams are processed once more on the proxy machine and re-sent, the path gets longer; for timing-sensitive traffic such as game traffic, this adds variability on top of the average latency. In other words, what is technically possible may not deliver the desired result in practice.
If one of the conditions is not met, the result is a silent fallback: no error appears, the game is playable, but the traffic does not go through the proxy. The only way to detect this is to measure. The details of the mechanism SOCKS5 UDP support in the article, and the version differences difference between SOCKS4 and SOCKS5 article.
DIAGRAMThe paths a server join request branches into
You can scroll the diagram horizontally to inspect it
A single "join" action branches into four separate network jobs; your proxy rule covers only some of them.
An exit plan for your Garry's Mod setup
In download-heavy use, bandwidth is decisive; for panel and administrative access, a static address is.
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Hosting a game from your own machine: address translation and hole punching
When you start a multiplayer session from within the game, your machine becomes both client and server at once. For your friends to reach you, packets arriving from outside your home network must be delivered to the right device. Almost all home networks sit behind address translation (NAT), and that translation does not inherently know which device an inbound request belongs to.
The solution usually comes in two ways: an explicit port forwarding rule on the router, or both sides sending packets outward to create a mapping — that is, hole punching. The second works together with the platform's relay and matchmaking infrastructure, and in most cases happens without the user noticing.
A proxy is not a solution in this picture. A forward proxy routes outbound requests; it does not accept inbound connections. What is more, because an intervening relay point changes the source address the other side sees, it can break mapping logic that relies on discovering one's own address. The distinction between the two concepts the difference between a proxy and NAT article.
Then there is translation on the carrier side. If your home line is behind carrier-grade address translation (CGNAT), you have no public address of your own and the port rule you write on your router is not visible from outside. In that case the only realistic path is to host the session on a reachable machine or to rent a server outside the home. The concept itself What is CGNAT article.
Warning
Adding a proxy to solve a connection problem usually makes diagnosis harder. First clarify the router and firewall side; bring the proxy in only when you genuinely want to route outbound traffic.
Where the two protocols overlap and where they part ways
The choice between an HTTP proxy and SOCKS5 depends on the type of traffic to be carried. Both carry TCP-based streams; content downloads, store pages and web-based server panels work fine over either protocol. The distinction begins outside this common ground.
An HTTP proxy sits at the application layer: it can read plain HTTP requests, add headers, and cache. These capabilities are useful in web traffic, not in games. SOCKS5, by contrast, does not interpret the protocol it carries; it is therefore more compatible with non-web clients and has a defined path for UDP.
Authentication also differs. An HTTP proxy carries the credentials in the request header and, when they are missing, returns 407 a response. In SOCKS5, authentication happens during the handshake before any data flows; failure surfaces earlier and more quietly. Knowing how a given client reports which error speeds up diagnosis.
The practical decision can be summed up like this: if you will only route downloads and the web side, either protocol will do. If you also want to cover the game traffic, SOCKS5 is the only candidate — and even then it is no guarantee. The full comparison protocol selection guide .
DIAGRAMThe overlapping and diverging areas of HTTP proxy and SOCKS5
You can scroll the diagram horizontally to inspect it
The common ground is TCP-based streams; the divergence begins with UDP transport and application-layer capabilities.
Setup, verification and choosing the exit type
Choose the configuration point according to your scope. A system-wide setting affects every application and has significant side effects; an app-based rule covers only the process you select. On a gaming machine, the latter usually produces a more predictable result.
Field
Example
Note
The server sends
proxy.example.com
The hostname given in the panel
Port
8080
Indicates the port, not the protocol
Username
username
Required on an authenticated exit
Password
password
Not to be shared; obtained from the panel
Verify with two tools: for whether the exit is alive proxy checker tool, and for whether the browser is leaking an address outside the proxy the WebRTC leak test. The second is especially relevant for those managing browser-based panels through a proxy.
After verifying the setup, note the result: which profile, which exit and which date you tested with. When a slowdown appears a month later, without a reference to compare against you cannot get beyond saying "it used to be better". Repeating the same measurement at different times of day is also a worthwhile habit on shared pools.
On the exit type side the decision is straightforward. For high-volume downloads and administrative work that requires a static address, datacenter proxy is sufficient and the most economical option. Scenarios that require a subscriber-line profile are outside the scope of this page; moving to an expensive pool for a game session is in most cases unnecessary spending.
Community rules and terms of service
On community servers, the party that sets the rules is the server administrator. The address you connect from is visible to the administrator, connection logs are kept, and the administrator has the authority to restrict access in case of a rule violation. If you join a community regularly, keeping your exit static is the path of least friction.
A proxy is not a tool related to the game's file integrity and version checks; this page does not describe such a use. Routing only changes where the connection comes from; the client's own checks keep working exactly as they did.
If you are on the server-operating side, the same rule applies to you. Your players' connection details are held by you, and that is a responsibility: determining what you store and for how long, who has access and when you delete it is part of administration. The privacy side of keeping logs logging and privacy is addressed within a similar framework in the article.
Finally, expectation management: a proxy is not a performance product. Every hop added to the path lengthens it. The places where it creates value are using a permitted address when leaving a restricted network, connecting to an administration panel from a static address, and verifying how content looks from another country. What these scenarios have in common is visibility, not speed.
Garry's Mod and proxies: common questions
01Does the content downloaded while connecting to a server go through the proxy?
Yes. Because server content is pulled from a separate web server over HTTP, both an HTTP proxy and SOCKS5 can carry this traffic. The game session itself is UDP, so the same rule does not cover it.
02Can I route the game traffic through a proxy?
Only with SOCKS5, and only when UDP ASSOCIATE is supported on both the server and the client. Most game clients have no such awareness; if the condition is not met, the client silently connects directly.
03I opened my own server and my friends cannot connect. Will a proxy fix it?
No. This is an inbound connection problem, and the fix is port forwarding or a firewall rule on the router. A forward proxy only routes outbound requests; adding it to the path also makes diagnosis harder.
04Is the server port always the same?
The traditional default of the Source engine is 27015/UDP, but administrators can change it and hosting providers use different ranges. The port appended to the server address is what is binding; do not proceed on assumption.
05Will using a proxy improve my connection?
The expectation should be the opposite. Because an extra hop is inserted, the path gets longer. A proxy is not a performance tool but a routing decision that changes where the connection appears to come from.
06Can the server administrator see the address I connect from?
Yes, the address the connection comes from is visible to the administrator and can be logged. In communities with strict rules, an unusual exit may lead to further questions; on servers you join regularly, a static exit creates less friction.
07Which exit type is sufficient?
For downloads and administrative access, an exit with strong bandwidth and a static address is enough. Scenarios that require a subscriber-line profile are not necessary for this use and create unnecessary cost.