Port 5999CVSup
CVSup is a network utility designed primarily for synchronizing source trees between a central repository and client systems. It efficiently manages file transfers, supporting incremental or partial updates to reduce bandwidth consumption. Mainly used in FreeBSD development environments, CVSup helps ensure that developers and users maintain up-to-date versions of source code more reliably than traditional downloading methods..
- transport
- tcp
- in transit
- cleartext
- assignment
- official
- risk
- 4/10
- lookups
- 4,079
single transport
payload readable on path
registered with iana
caution
rank 982 of 993 · top 99%
Technical Details
what runs on :5999CVSup—short for 'CVS Updater'—is a software utility that facilitates efficient distribution and synchronization of files across multiple machines. It is primarily used to mirror large source trees from a master server to client systems, leveraging the Modula-3 programming language which allows for multi-threaded file transfer and compression techniques to optimize bandwidth usage.
Operating on port 5999/TCP, CVSup employs a client-server model. Clients initiate connections to retrieve repository updates, transferring only file differences (deltas) rather than entire files. This technique is especially effective for rapidly propagating changes in large codebases, such as the FreeBSD Ports collection, without overwhelming network resources.
Because CVSup is built around CVS repositories, it manages checkouts and updates directly from source code management systems. Although long popular in BSD environments, its usage has declined due to migration toward newer version control systems like Subversion and Git, which handle synchronization differently, often over HTTPS.
Security Information
exposure of :5999risk score
4/ 10caution
worth attention. how exposed you are depends on configuration — don't leave it reachable from the internet without a reason.
file transfer averages 4.1 across 114 ports — this one sits 0.1 below.
in transit
cleartext
credentials and payloads are readable by anyone on path
assignment
official
registered with iana for this service — scanners fingerprint it by number
reachable over
tcp
every listening transport is another surface to filter at the edge
security overview
Common Vulnerabilities:
- Unencrypted communication over plaintext TCP can expose repository data and credentials to interception.
- Potential for man-in-the-middle attacks where an attacker relays or tampers with transferred data.
- CVSup servers may be targeted for denial-of-service by overwhelming connection attempts on port 5999.
Common Mitigations:
- Restrict access to trusted IP ranges using firewalls and access control lists.
- Encapsulate CVSup connections within a secure tunnel such as SSH or VPN to provide encryption.
- Regularly patch the CVSup server software to reduce exploit risk.
- Monitor port 5999 for unusual activity patterns indicating scanning or attack attempts.
Related Ports
the 8 most looked-up other ports in file transfer — 114 ports carry that label.
| port | service | risk | |||
|---|---|---|---|---|---|
| :9080 | Groove RPC | TCPUDP | Web Services | caution | 70.8k |
| :17500 | Dropbox LAN Sync | TCPUDP | File Transfer | caution | 43.7k |
| :548 | Apple Filing Protocol | TCP | File Transfer | caution | 36.8k |
| :7000 | Vuze HTTPS Tracker | TCPtls | Security | caution | 28.9k |
| :1337 | PowerFolder P2P | TCP | Security | caution | 27.1k |
| :9001 | SharePoint Authoring | Web Services | caution | 26.3k | |
| :8080 | FilePhile Relay | UDP | File Transfer | caution | 25.6k |
| :1337 | WASTE Encrypted Sharing | TCP | Security | caution | 22.9k |
risk mix of the 8 listed
- caution100%
1 of 8 encrypted