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AWS transfer medium security documentation change

Service: transfer · 2025-07-04 · Security-related medium

File: transfer/latest/userguide/sftp-for-transfer-family.md

Summary

Added section 'FTP and FTPS Network Load Balancer considerations' with security recommendations including disabling health checks on ports 8192-8200, enforcing TLS session resumption, and migration guidance away from NLBs

Security assessment

The changes explicitly address security configurations by recommending TLS enforcement (CWE-319), port hardening, and migration from NLBs to improve security posture. References a security blog post about server hardening.

Diff

diff --git a/transfer/latest/userguide/sftp-for-transfer-family.md b/transfer/latest/userguide/sftp-for-transfer-family.md
index 67eea66b6..53a64994e 100644
--- a//transfer/latest/userguide/sftp-for-transfer-family.md
+++ b//transfer/latest/userguide/sftp-for-transfer-family.md
@@ -5 +5 @@
-Identity provider optionsAWS Transfer Family endpoint type matrix
+Identity provider optionsAWS Transfer Family endpoint type matrixFTP/FTPS NLB considerations
@@ -18,0 +19,2 @@ This topic provides details for creating and using AWS Transfer Family server en
+  * FTP and FTPS Network Load Balancer considerations
+
@@ -87,0 +90 @@ Client firewall allow list |  You must allow the DNS name of the server. Because
+IP address type | IPv4 (default) or dual-stack (IPv4 and IPv6) | IPv4 only (dual-stack not supported) | IPv4 (default) or dual-stack (IPv4 and IPv6) | IPv4 only (dual-stack not supported)  
@@ -111,0 +115,15 @@ If you use a Network Load Balancer, the AWS Transfer Family CloudWatch logs show
+## FTP and FTPS Network Load Balancer considerations
+
+While we recommend avoiding Network Load Balancers in front of AWS Transfer Family servers (see [Avoid placing NLBs in front of AWS Transfer Family servers](./infrastructure-security.html#nlb-considerations)), if your FTP or FTPS implementation requires an NLB, follow these recommendations:
+
+  * Turn off health checks on ports 8192-8200. Consider using port 21 instead for health checks.
+
+  * Enable TLS session resumption by setting `TlsSessionResumptionMode = ENFORCED`.
+
+  * If possible, migrate away from using an NLB to take full advantage of AWS Transfer Family performance and connection limits.
+
+
+
+
+For additional guidance on NLB alternatives, contact the AWS Transfer Family Product Management team through AWS Support. For more details on improving your security posture, see the blog post [Six tips to improve the security of your AWS Transfer Family server](https://aws.amazon.com/blogs/security/six-tips-to-improve-the-security-of-your-aws-transfer-family-server/)
+