Tutorials / Networking

Check Public Reachability and Reverse DNS

intermediate25 minLast reviewed: 2026-07-15Target OS: Ubuntu 24.04 LTS

Written by uNode Engineering; reviewed by uNode Operations.

Guest mapping, local listener, firewall, external TCP, forward DNS, PTR, and support-evidence checks reviewed.

A successful ping does not prove SSH is listening, and an open port does not prove credentials are valid. Test the path in layers. PTR support varies by provider and address pool.

Illustration for How to Check VPS Reachability and Reverse DNS

Prerequisites

  • The VPS public IPv4 and server ID.
  • Console access if SSH is unavailable.
  • A second network from which to test.
Open console server deploy

Recommended plans

Starter

1 vCPU, 3 GB RAM, 20 GB NVMe SSD, 10 TB transfer

Standard

2 vCPU, 4 GB RAM, 30 GB NVMe SSD, 10 TB transfer

Step 1

Verify the address mapping

Confirm that the IP displayed in the console matches the guest interface and did not change after lifecycle actions.

ip -br address
ip route

Step 2

Verify the service is listening

Check the local socket and firewall before blaming upstream routing.

ss -lntp | grep ':22'
ufw status verbose
systemctl status ssh --no-pager

Step 3

Test from outside

Use a second network or monitoring host to test the exact TCP port. Record time, source network, destination IP, and result.

nc -vz <server-ip> 22
ssh -vvv <username>@<server-ip>

Step 4

Check forward and reverse DNS

Forward A and reverse PTR records are independent. Contact support if the console does not expose PTR for this provider.

dig +short A host.example.com
dig +short -x <server-ip>

What's next

Connect with SSHConfigure DNS and HTTPSContact support