Is port 504 (Citadel) dangerous?

Port 504 is classified as medium risk. It is commonly exposed but consider using encrypted alternatives where available and monitor activity.

Should port 504 be open on my firewall?

Port 504 can be open but should be monitored closely. Keep the service updated and prefer encrypted alternatives where available.

Port 504 (Citadel) uses the TCP transport protocol and falls under the Messaging category.

:504 (TCP)

Medium 风险

TCP — Messaging

On this page

端口号 504

服务名称 Citadel

传输协议 TCP

类别 Messaging

安全风险 Medium

端口范围知名端口 (0-1023)

Port 504 is assigned to Citadel, an open-source groupware and messaging server providing email, calendaring, and bulletin board services.

TCP Messaging

端口504（Citadel）被归类为中等风险。虽然此服务通常会暴露，但请在可用时考虑使用加密替代方案。

建议：保持服务更新。监控日志以发现异常活动。