I'm managing an on-prem Gnu/Linux cluster which performs as an API gateway. There are two servers in ESB cluster(Say ESB1 and ESB2). From ESB1 server, it is possible to ping to ESB2 server using the hostname, even though IP and host is not included in ESB1's /etc/hosts

Recently we added one VM(hosted in virtual box) to our ESB cluster(Say ESB3). ESB3 is ping-able using the IP from ESB1/ESB2 servers. But it is not ping-able from ESB1/ESB2 using ESB3's hostname unless it is included in ESB1 and ESB2's /etc/hosts.

What is the reason for this difference?

  • 3
    Somebody configured DNS entries for those hosts, presumably
    – muru
    Apr 8, 2020 at 5:36
  • What operating system? Apr 8, 2020 at 6:46
  • Old ESB on-prem servers - CentOS 7 New ESB VM - RHEL7 Apr 8, 2020 at 7:05

1 Answer 1


You just need to resolve the host-name into an IP address. You can do this in many ways:

  • Manually. Just lookup the IP address, and type it.
  • Configure it in a DNS server. This server can be public or private.
  • Configure zeroconf/avahi/bonjore/mDNS/DNS-SD (peer DNS discovery).

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