# Networking and reverse DNS
Source: https://docs.webgee.com/en/servers/server-networking





Manage your cloud server's network configuration. Applies to all VPS and
dedicated servers.

<img alt="The Network tab showing the primary network, IPv4 addresses and DNS resolvers" src="__img0" />

## Primary network [#primary-network]

The details your server's own configuration must match:

| Field     | What it is                           |
| --------- | ------------------------------------ |
| Interface | The network device name, e.g. `ens3` |
| MAC       | The interface's hardware address     |
| Type      | Public or private                    |
| Speed     | Inbound and outbound limits          |

## IPv4 addresses [#ipv4-addresses]

Each address is listed with its **gateway**, **netmask** and **resolvers**. You
need all three if you ever configure networking by hand — after a manual OS
installation, for instance.

## Reverse DNS [#reverse-dns]

Reverse DNS maps your IP address back to a hostname. Select **Reverse DNS**
beside the address to set it.

<Callout type="warn">
  **Set this before sending any email.** Most receiving mail servers reject or
  heavily penalise mail from an IP with no reverse DNS, or whose reverse DNS does
  not match the sending hostname. It is the single most common reason mail from a
  new VPS goes nowhere.
</Callout>

Set it to the server's fully qualified hostname — `mail.example.com` — and make
sure a matching forward `A` record exists pointing back to the same IP. The two
must agree.

## DNS resolvers [#dns-resolvers]

Your server needs two resolvers to look up domain names. The system defaults are
Cloudflare's `1.1.1.1` and `1.0.0.1`.

Change them under **IPv4 Public DNS Resolvers** if you have a reason to — a
filtering resolver, or your own internal DNS. Otherwise leave them.

<Callout type="info">
  Changing resolvers here sets what a **rebuilt** server receives. On a running
  server, also update `/etc/resolv.conf` or your network configuration, or it
  keeps using the old values.
</Callout>

## Check it worked [#check-it-worked]

Reverse DNS, from any machine:

```bash
dig +short -x 203.0.113.10
```

It should return your hostname. Propagation can take a few hours.

Forward and reverse agreement:

```bash
dig +short mail.example.com
```

That should return the same IP you just looked up.

## Related [#related]

* [Network issue troubleshooting guide](/en/servers/network-issue-troubleshooting-guide)
* [Provide a traceroute using MTR](/en/servers/how-to-provide-a-traceroute-using-mtr-a-comprehensive-guide)
* [SPF records for WebGee hosting](/en/email/what-are-the-correct-spf-records-when-using-webgee-hosting)