Port 520EFS Server
The Extended File Name Server (EFS) operates on port 520. It facilitates handling of file name mapping and directory services, often associated with older UNIX and DEC systems to provide name services over networks. Although largely supplanted by modern directory protocols, it historically played a role in distributed file environments..
- transport
- tcp
- in transit
- cleartext
- assignment
- official
- risk
- 4/10
- lookups
- 8,169
single transport
payload readable on path
registered with iana
caution
rank 616 of 993 · top 62%
1 other service is registered on port 520. compare all 2 →
Technical Details
what runs on :520-
Overview: Port 520 hosts the Extended File Name Server (EFS), historically used in DECnet and UNIX-based environments for mapping file names and managing directory services across the network. It helped users locate and access files on remote systems transparently.
-
Protocol Details: EFS uses a request-response method for translating file references and providing file-related metadata. It typically functioned alongside network file systems or as a companion service to streamline distributed file access.
-
Deployment Context: While employed on TCP port 520, its usage diminished with the advent of more sophisticated protocols like LDAP and advances in network file systems (NFS, SMB/CIFS). Today, port 520 is more commonly known for RIP, but historically it served multiple roles.
Security Information
exposure of :520risk 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:
- Unauthenticated Access: Older EFS implementations often lacked strong authentication, making them vulnerable to unauthorized data access.
- Man-in-the-Middle Attacks: Unencrypted communications allowed interception and manipulation of directory information.
- Service Misconfiguration: Weak configurations or exposure of internal services could increase attack surface.
-
Mitigations:
- Service Deactivation: Disable EFS if it is legacy and no longer required.
- Access Restrictions: Filter port 520 access using firewalls and ACLs, limiting exposure to trusted hosts.
- Encryption and Segmentation: Use encrypted tunnels and network segmentation to protect legacy services during transition.
- Migration: Transition to modern directory services with integrated security features.
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