Port 158DMSP
Distributed Mail Service Protocol (DMSP) was designed as an email transport protocol facilitating distributed mail delivery and management across multiple servers. Operating on port 158, DMSP supports both TCP and UDP for flexible communication paths. While largely supplanted by more modern and secure protocols, it historically aimed to optimize email routing in decentralized architectures..
- transport
- tcp · udp
- in transit
- cleartext
- assignment
- unofficial
- risk
- 4/10
- lookups
- 6,848
2 transports registered
payload readable on path
used by convention
caution
rank 746 of 993 · top 75%
Technical Details
what runs on :158Overview:
DMSP (Distributed Mail Service Protocol) was developed to support distributed email systems where multiple mail servers collaborate to handle message routing, storage, and delivery. It allows clients to interact with server clusters, optimizing email retrieval and management in environments without centralized infrastructure.
Protocol Design:
DMSP utilizes both TCP and UDP, granting flexibility between connection-oriented and connectionless communication, which caters to various network scenarios. The protocol defines commands for message transfer, mailbox synchronization, address resolution, and status checks. Its design accommodates failover and redundancy, enabling resilient email services.
Current Relevance:
Despite its innovative approach during its inception, DMSP has been rendered obsolete by protocols like SMTP, IMAP, and POP3. Consequently, it is rarely encountered in modern deployments and lacks ongoing development or substantial documentation.
Security Information
exposure of :158risk score
4/ 10caution
worth attention. how exposed you are depends on configuration — don't leave it reachable from the internet without a reason.
email averages 3.9 across 42 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
tcp · udp
udp is connectionless — source addresses are trivially spoofed and it is a reflection favourite
security overview
Common Vulnerabilities:
- Lack of Built-in Encryption: Communications over DMSP are transmitted in plaintext, exposing sensitive email data to interception.
- Weak Authentication: Early designs may lack strong authentication mechanisms, making them susceptible to spoofing or unauthorized access.
- UDP-based Attacks: Using UDP can open avenues for reflection or amplification attacks.
Mitigations:
- Network administrators should avoid exposing port 158 externally if not explicitly required.
- If legacy systems depend on DMSP, encapsulate communication within secure VPN tunnels.
- Deploy strict firewall rules to regulate access.
- Transition to secure, modern email protocols with robust encryption and authentication support.
Related Ports
the 8 most looked-up other ports in email — 42 ports carry that label.
| port | service | risk | |||
|---|---|---|---|---|---|
| :143 | IMAP | TCPUDP | caution | 20.7k | |
| :995 | POP3S | TCPtls | caution | 18.8k | |
| :109 | POP2 | TCP | caution | 17.9k | |
| :2096 | cPanel SSL Webmail | TCPtls | Web Services | safe | 17.4k |
| :110 | POP3 | TCP | caution | 15.5k | |
| :993 | IMAPS | TCPtls | caution | 14.5k | |
| :1352 | Lotus Notes RPC | TCP | caution | 12.3k | |
| :24 | Private Mail | TCPUDP | caution | 11.7k |
risk mix of the 8 listed
- safe13%
- caution88%
3 of 8 encrypted