Configure persistence for MCP Gateway

Last published : Sep 24, 2026
MCP involves multi-step, stateful interactions. Without persistence, requests from the same session might land on different servers, resulting in session lookup failures, such as "Session not found".
NetScaler® uses MCP session identifiers to enforce persistence, ensuring reliability and correctness for multi-step MCP interactions. It ensures that all requests belonging to a single MCP session are consistently routed to the same backend MCP server using session-aware persistence. As a result, no client-side changes are required, because NetScaler:
  • Ensures session continuity.
  • Prevents backend state loss.
  • Improves reliability of tool/execution.
Related information

Configure persistence by using the CLI

Configure rule-based persistence on the load balancing virtual server using MCP-specific expressions.
set lb vserver lb_app1_mcp SSL 0.0.0.0 0 -persistenceType RULE -rule "http.req.header(\"Mcp-Session-Id\")" -resRule "http.res.header(\"Mcp-Session-Id\")"

Validation

  1. Initiate an MCP session.
  2. Repeat the tool calls using the same session.
  3. Verify whether the same backend server handles all the requests.

Troubleshooting

Session errors

Check the persistence rule.

Uneven load

Review the timeout settings and backend capacity.

Non-sticky behavior

Verify the header and session extraction configuration.