I have a default installation of Elasticsearch which I am trying to query from a third party server. However, it seems that by default this is blocked. 
Is anyone please able to tell me how I can configure Elasticsearch so that I can query it from a different server?
In config/elasticsearch.yml, put network.host: 0.0.0.0.
And also add Inbound Rule in firewall for your ElasticSearch port(9200 ByDefault).
It worked in ElasticSearch version 2.3.0
Allowing remote access to Elasticsearch