Elasticsearch does not listen on ipv4

[sharbich (Stefan Harbich)]

Hello, my dears,
I installed Elasticsearch on my Debian Buster Server. The following ports have been opened.

root@dsme01:~# netstat -tulpen | grep 192.168.150.20
tcp6       0      0 192.168.150.20:9200     :::*                    LISTEN      137        487760242  19429/java          
tcp6       0      0 192.168.150.20:9300     :::*                    LISTEN      137        487760026  19429/java  

I notice that only ipv6 connections are displayed. Why?
My elsaticsearch.yml looks like this

root@dsme01:~# cat /etc/elasticsearch/elasticsearch.yml 
path.data: /var/lib/elasticsearch
path.logs: /var/log/elasticsearch
network.host: elasticsearch.intern.example.com
xpack.security.enabled: true
xpack.security.enrollment.enabled: true
xpack.security.http.ssl:
  enabled: true
  keystore.path: certs/http.p12
xpack.security.transport.ssl:
  enabled: true
  verification_mode: certificate
  keystore.path: certs/transport.p12
  truststore.path: certs/transport.p12
cluster.initial_master_nodes: ["dsme01"]
http.host: elasticsearch.intern.example.com
transport.host: elasticsearch.intern.example.com
path.data: /var/lib/elasticsearch
path.logs: /var/log/elasticsearch

What am I doing wrong?

Greetings from Stefan Harbich

[DavidTurner]

Are you referring to the tcp6 in the netstat output? That's normal, or at least not unexpected in certain configs, and doesn't indicate a problem. There's some sort of compatibility layer in play that makes these sockets appear to be using IPv6 but the addresses are IPv4 addresses and that's what really matters.