Start/notes.ini Parameters/Server_MaxUsers

Server_MaxUsers

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Parameter: Server_MaxUsers
Short description: Maximum number of concurrently logged-in users – further logins are rejected (SERVER_MAXUSERS_TYPE controls the behavior).

Profile

Parameter
Server_MaxUsers
Category
Performance / Memory
Component
Server
Available since
R5
Supported versions
9.0.1, 10.0, 11.0, 12.0, 14.0, 14.5
GUI equivalent
Server document (Server Tasks → Limits)
Possible values
0 = no limit (default), positive integer = user limit

Description

Server_MaxUsers defines how many users may concurrently authenticate to the server via NRPC. Once the value is reached, the server responds to new connections with “Server is restricted to administrative use only” (or, depending on SERVER_MAXUSERS_TYPE, redirects to another server).
Typical use: load protection on large mail servers, together with MailClusterFailover in cluster pairs as a failover trigger.

Example configuration

Server_MaxUsers=750
SERVER_MAXUSERS_TYPE=2

Notes & pitfalls

  • 0 disables the limit entirely (default).
  • Behavior at the limit depends on SERVER_MAXUSERS_TYPE (1 = restricted, 2 = cluster failover).
  • The value should match the hardware (CPU, RAM, NSF_Buffer_Pool) and licensing.
  • Live monitoring via show stat Server.Users and Server.Users.Peak.
  • Affects only NRPC – HTTP / IMAP sessions are limited separately.
  • In a cluster, together with Server_Availability_Threshold, this implements a failover scenario.