Port 27015Source Engine Server
Port 27015 is widely used by game servers running Valve's GoldSrc and Source engines. It allows multiplayer connection handling for popular games like Counter-Strike, Team Fortress, and Half-Life. The port facilitates client-server communications, server queries, and matchmaking. Although primarily associated with gaming, the port's openness can sometimes expose servers to attacks if not properly secured..
- transport
- unknown
- in transit
- cleartext
- assignment
- unofficial
- risk
- 4/10
- lookups
- 18,729
single transport
payload readable on path
used by convention
caution
rank 141 of 993 · top 14%
Technical Details
what runs on :27015Port 27015 is commonly utilized for dedicated game servers built on Valve's GoldSrc and Source engine platforms. These engines support iconic titles including Counter-Strike, Team Fortress Classic, Half-Life, Left 4 Dead, Portal, and Garry's Mod. Server administrators configure this port to receive player connections, synchronize game data, and manage in-game events.
The port handles both gameplay data and out-of-band queries, such as retrieving server information, player lists, and server status. For matchmaking and updates, the engines implement protocols over this port—either UDP or sometimes TCP, depending on the server settings and specific game requirements. Most notably, Steam employs a master server query system leveraging this port for server listings.
Although traditionally the engine communicates over UDP, custom server setups may employ other transport protocols, but SCTP use is practically nonexistent here. The port remains unofficially standardized in the gaming community as the default connection point for Source and GoldSrc servers hosted on personal or rented infrastructure.
Security Information
exposure of :27015risk score
4/ 10caution
worth attention. how exposed you are depends on configuration — don't leave it reachable from the internet without a reason.
network services averages 3.9 across 604 ports — this one sits 0.1 above.
in transit
cleartext
credentials and payloads are readable by anyone on path
assignment
unofficial
used by convention, not registered — what answers here varies by deployment
reachable over
unknown
every listening transport is another surface to filter at the edge
security overview
Common Vulnerabilities:
- Denial of Service (DoS) attacks: Attackers can exploit game protocol vulnerabilities or flood bandwidth to disrupt services.
- Server exploits: Legacy or unpatched engines are susceptible to remote code execution through malformed packets.
- Information leakage: Open server queries over this port can reveal sensitive information like game versions, plugins, or even IP addresses of connected players.
Common Mitigations:
- Keep server software and plugins up to date with the latest security patches.
- Employ firewalls to restrict port access to trusted IP ranges.
- Use rate limiting and anti-DDoS solutions to prevent flooding attacks.
- Disable unnecessary server queries or obfuscate server information.
- Monitor logs regularly for unusual or suspicious activity.
Related Ports
the 8 most looked-up other ports in network services — 604 ports carry that label.
| port | service | risk | |||
|---|---|---|---|---|---|
| :9080 | Groove RPC | TCPUDP | Web Services | caution | 70.8k |
| :6543 | Jetnet | UDP | Network Services | caution | 65.3k |
| :5938 | TeamViewer | TCPUDP | Remote Access | caution | 65.0k |
| :8291 | Winbox MikroTik Admin | TCP | Security | caution | 62.9k |
| :3233 | WhiskerControl Protocol | TCPUDP | Network Services | caution | 61.9k |
| :3268 | Microsoft Global Catalog (GC) | TCPUDP | Security | caution | 54.6k |
| :135 | Microsoft EPMAP | TCPUDP | Security | caution | 51.9k |
| :3128 | Tatsoft Default HTTP Proxy | TCP | Web Services | caution | 46.8k |
risk mix of the 8 listed
- caution100%
0 of 8 encrypted