This is not an HTTP port – How to solve this Elasticsearch error

Opster Team

July-20, Version: 1.7-8.0

Before you begin reading this guide, we recommend you try running the Elasticsearch Check-Up which can resolve issues that cause many errors.

This guide will help you check for common problems that cause the log ” This is not an HTTP port ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: node.

Advanced users might want to skip right to the common problems section in each concept or try running the Check-Up to analyze Elasticsearch configuration and help resolve this error.

Log Context

Log “This is not an HTTP port”classname  is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 private static int readHeaderBuffer(BytesReference headerBuffer) throws IOException {
 if (headerBuffer.get(0) != 'E' || headerBuffer.get(1) != 'S') {
 if (appearsToBeHTTPRequest(headerBuffer)) {
 throw new HttpRequestOnTransportException("This is not an HTTP port");
 if (appearsToBeHTTPResponse(headerBuffer)) {
 throw new StreamCorruptedException("received HTTP response on transport port; ensure that transport port (not " +
 "HTTP port) of a remote node is specified in the configuration");


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