LB closes the connection to the pool member and logs status code 499.

Products

• VMware NSX

Issue/Introduction

• The connection between the Load Balancer (LB) and the pool member is terminated by the LB while waiting for an HTTP response from the pool member.
• The client cancels the request due to reasons such as a response timeout on the client side.
• The following status code 499 is recorded in the Edge syslog:

2026-01-23T05:45:35.818Z LOAD-BALANCER Operation.Category: 'LbAccessLog', Vs.Ip: '##.##.##.##', Vs.Port: '###', Pool.Name: '############', PoolMember.Ip: '##.##.##.##', PoolMember.Port: '###', Client.Ip: '##.##.##.##', Client.Port: '###', Snat.Ip: '##.##.##.##', Snat.Port: '###', HttpRequest.Method: 'POST', HttpRequest.X-Fwd-For: '##.##.##.##', HttpRequest.Uri: '/#####/#####/#####', HttpRequest.Host: '#####.#####.#####', HttpResponse.Status: '499', HttpResponse.StatusCategory: '4xx', HttpResponse.Size: '0', HttpResponse.ServerTime: '-', HttpResponse.TotalTime: '303.709', Error.Reason: '-'

Environment

VMware NSX

Cause

HTTP status code 499 indicates that the client side has canceled the request.

When a client sends an HTTP request that takes a long time to process to the NSX LB VIP, and the HTTP response is not returned within the client-side timeout period, the client cancels the request.

In this case, the NSX LB records status code 499 in the access log.

Resolution

There is a possibility that the response timeout of the client-side application is short compared to the processing time on the server side.

Consider improving the response of the server-side application or increasing the number of pool members to distribute the workload.