Start/notes.ini Parameters/HTTPMaxConnectionsPerIP

HTTPMaxConnectionsPerIP

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Parameter: HTTPMaxConnectionsPerIP
Short description: Limits the number of concurrent open HTTP connections per source IP address – effective protection against simple DoS scenarios.

Profile

Parameter
HTTPMaxConnectionsPerIP
Category
HTTP / Web
Component
Server
Available since
10.0
Supported versions
10.0, 11.0, 12.0, 14.0, 14.5, 14.5.1
GUI equivalent
Configuration document
Possible values
Integer (typical 50 – 200); 0 = unlimited

Description

Individual clients or malicious bots can "exhaust" a web server by opening a very large number of concurrent connections. HTTPMaxConnectionsPerIP sets an upper bound: if a single source IP exceeds this value, the Domino HTTP task rejects further connections. This preserves capacity for regular clients. Especially on directly Internet-facing servers (without a WAF / reverse proxy in front), this is a sensible baseline hardening.

Example configuration

HTTPMaxConnectionsPerIP=100

Notes & pitfalls

  • Behind NAT, reverse proxies, or carrier-grade NAT, all clients appear with the same source IP – values that are too small block legitimate user groups.
  • For reverse-proxy architectures, configure the limit on the upstream component and keep the value on Domino moderate.
  • Takes effect after an HTTP restart (tell http restart).
  • Pairs with HTTPProcessRedirects, HTTP_SESSION_COOKIES_SECURE, and WAF / rate-limiting in the infrastructure.