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Port 220IMAP v3

IMAP version 3 (Internet Message Access Protocol) enables users to access and manage their email messages stored on a mail server in real time. It allows multi-device email synchronization, giving users flexibility to organize mail folders remotely and retrieve messages without downloading them permanently. This protocol version builds upon earlier iterations for improved client-server interaction, enhancing email management efficiency for both personal and organizational use..

inEmailNetwork Services
transport
tcp · udp

2 transports registered

in transit
cleartext

payload readable on path

assignment
official

registered with iana

risk
4/10

caution

lookups
8,622

rank 587 of 993 · top 59%

Technical Details

what runs on :220

IMAP version 3 (IMAP3) is an application layer protocol designed to enable online and offline email message management. Unlike its predecessor POP, IMAP3 maintains messages on a central server, allowing users to access their mail from multiple locations or devices without duplicating or losing information. With support for selective message downloading, server-side folder organization, and message flagging, IMAP enhances user flexibility and mailbox control.

Clients initiate a TCP or UDP connection to port 220 on the email server, where commands like FETCH, STORE, and SEARCH facilitate efficient email synchronization. IMAP3 extends some functionalities compared to IMAP2 by supporting improved command sets and enhanced status responses from the server. This two-way communication minimizes data transfers by only retrieving requested message components, optimizing bandwidth while ensuring timely mail access.

IMAP operates primarily over reliable TCP connections for data transfer integrity, but some implementations may support UDP for limited operations or notifications. In modern deployment, IMAP is typically secured with TLS encryption (using IMAPS on port 993), but IMAP3 on port 220 does not provide built-in encryption, which needs to be layered externally if security is a concern.

Security Information

exposure of :220

risk 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

official

registered with iana for this service — scanners fingerprint it by number

reachable over

tcp · udp

udp is connectionless — source addresses are trivially spoofed and it is a reflection favourite

security overview

Common Vulnerabilities:

  • IMAP3 on its default port 220 transmits data in plaintext, exposing credentials and email contents to eavesdropping and man-in-the-middle attacks.
  • Weak or default authentication mechanisms can be exploited for unauthorized mailbox access.
  • IMAP servers may be vulnerable to brute-force attacks, command injection, and buffer overflow vulnerabilities if not properly configured or patched.
  • Attackers can abuse IMAP features like folder creation or message flagging to perform denial-of-service or resource exhaustion on the mail server.

Common Mitigations:

  • Implement strong, multi-factor authentication and enforce account lockouts after failed login attempts.
  • Wrap IMAP3 in encrypted tunnels such as SSL/TLS or deploy encrypted alternatives (IMAPS) to prevent data interception.
  • Regularly update and patch IMAP server software to address known vulnerabilities.
  • Restrict access with firewall rules and monitor traffic for anomalous patterns indicating brute-force or exploitation attempts.
  • Review and limit IMAP server permissions, disable unnecessary commands, and conduct regular security audits.

Related Ports

all 42 in email →

the 8 most looked-up other ports in email — 42 ports carry that label.

portservicerisk
:143IMAPcaution
:995POP3Scaution
:109POP2caution
:2096cPanel SSL Webmailsafe
:110POP3caution
:993IMAPScaution
:1352Lotus Notes RPCcaution
:24Private Mailcaution

risk mix of the 8 listed

  • safe13%
  • caution88%

3 of 8 encrypted