Question

Completely block IP from accessing server and postgresql

Hi,

OS - UBUNTU 20.04

Problem:

Recently our server and database (postgresql) being attacked by specific IP (45.155.204.146). The IP keep on trying to connect to our database and we believe subsequently cause our postgresql service to shutdown.

Postgresql log example:

2022-04-03 09:51:31.239 UTC [366035] pgsql@postgres FATAL:  no pg_hba.conf entry for host "45.155.204.146", user "pgsql", database "postgres", SSL off
2022-04-03 09:52:59.562 UTC [366104] postgres@postgres FATAL:  no pg_hba.conf entry for host "45.155.204.146", user "postgres", database "postgres", SSL off
2022-04-03 09:53:37.846 UTC [366149] postgres@postgres FATAL:  no pg_hba.conf entry for host "45.155.204.146", user "postgres", database "postgres", SSL off
2022-04-03 09:54:04.698 UTC [285005] LOG:  received smart shutdown request

What have we done to prevent:

  1. Use ufw to allow only specific IP (our app server) to access port 5432/tcp
  2. Use ufw to specifically block that IP 45.155.204.146

We appreciate any suggestion and idea before we proceed with whole server redo.

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KFSys
Site Moderator
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• April 5, 2022

Hi @CuteGreenBlueMantaRay,

Usually, in such cases, it’s always best to just block the IP using your Firewall, that’s the most straightforward solution with the quickest results.

Whether it’s UFW or CSF or just plain IPTables, it doesn’t matter as long as you block it from there.