Port 873Rsync

Rsync is a fast and versatile file synchronization tool used primarily to efficiently transfer and synchronize files between hosts or within the same system. It minimizes data transfer by only moving the differences between files across secure or insecure channels, making it popular for backups and mirroring..

transport
tcp

single transport

in transit
cleartext

payload readable on path

assignment
official

registered with iana

risk
4/10

caution

lookups
6,337

rank 797 of 993 · top 80%

Technical Details

what runs on :873
  • Overview: Rsync operates by comparing timestamp and size to determine file changes, then transfers only the differences using delta encoding. This leads to significant bandwidth and time savings, aligning with efficient data management goals.

  • Protocol Operation: It runs typically over TCP on port 873 as a daemon service (rsyncd) for direct connections or encapsulated through SSH for encrypted transfers. The Rsync daemon supports anonymous or authenticated modes, and configuration is through the rsyncd.conf file specifying modules (directories/services).

  • Deployment: It is widely used in Linux/Unix environments, though it is cross-platform with appropriate clients. Administrators deploy Rsync for automated backups, server mirroring, and incremental file updates, given its lightweight differential transfer capabilities and scripting ease.

Security Information

exposure of :873

risk 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:

    • Unauthorized Access: Misconfiguration leading to open, writable modules or weak authentication can expose sensitive data or allow malicious uploads.
    • Data Interception: Default daemon mode does not encrypt traffic, making it susceptible to eavesdropping and man-in-the-middle attacks.
    • Abuse for Reconnaissance: Attackers may use rsync to enumerate files or exfiltrate data if improperly secured.
  • Common Mitigations:

    • Enforce Access Controls: Limit rsync modules via IP allow lists and strong authentication.
    • Use SSH Tunnels: Prefer running rsync over SSH to encrypt data in transit.
    • Restrict Write Permissions: Offer read-only access where possible, to minimize data manipulation risks.
    • Monitor & Update: Keep rsync updated to address security patches and monitor logs for unusual activity.

the 8 most looked-up other ports in file transfer — 114 ports carry that label.

risk mix of the 8 listed

  • caution100%

1 of 8 encrypted