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Port 10024Zimbra SMTP to Amavis

This port is commonly used within Zimbra Collaboration Suite for internal communication between the mail transfer agent (Postfix) and Amavis, an open-source content filter. It facilitates email scanning, virus filtering, and spam detection before mail delivery, ensuring cleaner email flows within an organization’s email infrastructure..

inEmailSecurity
transport
tcp

single transport

in transit
cleartext

payload readable on path

assignment
unofficial

used by convention

risk
4/10

caution

lookups
8,674

rank 584 of 993 · top 59%

Technical Details

what runs on :10024

Port 10024 is primarily used in the Zimbra Collaboration Suite, an open-source email and collaboration platform. Within Zimbra, this port serves for internal SMTP traffic between Postfix (the mail transfer agent) and the Amavis content filter. When Postfix receives an email, it forwards it over TCP port 10024 to Amavis for content scanning.

Amavis integrates antivirus and antispam tools, scanning the emails for malware, viruses, and unsolicited messages. Accepted mails are then handed back from Amavis to Postfix through a separate port for final delivery to the mailbox or onward routing. This separation ensures that incoming emails are filtered thoroughly before users engage with them.

Typically, this port operates internally within the server or trusted LAN environments, rather than being exposed externally. Proper functioning requires that both Postfix and Amavis are configured correctly to send and receive messages on port 10024, maintaining seamless scanning and delivery workflows within Zimbra’s architecture.

Security Information

exposure of :10024

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

unofficial

used by convention, not registered — what answers here varies by deployment

reachable over

tcp

every listening transport is another surface to filter at the edge

security overview

Port 10024, being used internally for scanning emails, can become a target if exposed externally or misconfigured. Common vulnerabilities include:

  • Spoofing attacks where malicious actors inject crafted messages during the communication
  • Relay abuses if access controls are lax, allowing unauthorized or unauthenticated use
  • Denial-of-Service (DoS) by overwhelming Amavis or the MTA with large volumes of spam or malformed messages
  • Man-in-the-middle attacks on unencrypted communication which could expose or alter email content

Mitigations involve:

  • Restricting port access to localhost or trusted internal networks via firewalls
  • Enabling SMTP authentication and proper access controls
  • Keeping Zimbra, Postfix, and Amavis updated with security patches
  • Optionally encrypting internal SMTP traffic using TLS or stunnel if higher security is required
  • Monitoring logs regularly to detect unusual activity

Because port 10024 handles unfiltered emails, its protection is crucial to prevent infection and abuse within an organization's messaging backbone.

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