Post 10.1 upgrade 400 response code from gateway for some clients

Products

• CA API Gateway

Issue/Introduction

After upgrading to gateway 10.1 some clients can not connect to the gateway and get 400 response code.

Enabling the tomcat logging shows there is a mismatch in the host header. 

API Gateway: How to see Tomcat logs when Clients are receiving Error 400 Bad Request response, no entries in SSG logs.

Environment

Release : 10.1

Resolution

The gateway is denying the request because the host header does not match the request host name 

Tomcat sees the host as mismatch when the request is including the host and port. 

The ncat utility send the request as GET     https://<servername:443>/connectivity 

while postman and curl are sending it as GET /connectivity this why it could not be reproduced with curl. 

We can workaround this in the listen port advanced properties you can set 

allowHostHeaderMismatch = true 

This should bypass the restriction for the host header introduced with the newer tomcat in gateway 10.1