---
title: Strong TCP sequence numbers
description: Strong TCP sequence numbers for preventing already-established TCP connections to the host system from being hijacked.
component: pingdirectory
version: 10.2
page_id: pingdirectory:pingdirectory_security_guide:pd_sec_strong_tcp_seq_nums
canonical_url: https://docs.pingidentity.com/pingdirectory/11.1/pingdirectory_security_guide/pd_sec_addl_mech_secure_comm.html
llms_txt: https://docs.pingidentity.com/pingdirectory/llms.txt
docs_for_agents: https://developer.pingidentity.com/build-with-ai/docs-for-agents.md
revdate: 2023-09-13T00:00:00Z
---

# Strong TCP sequence numbers

Use strong TCP sequence numbers to prevent already-established TCP connections from being hijacked.