OMC Cloud Firewall Guide

Short version: every OMC Cloud server comes with a free, built-in firewall in the cloud console. Turn it on in the server's Firewall tab, keep the Input Policy on DROP and the Output Policy on ACCEPT, and open only the ports you actually need (for example SSH on 22 or RDP on 3389), and only to IP addresses you trust. IP Sets and IP Aliases save you from typing the same addresses into every rule.

How do you enable the firewall?

1. Log in to the cloud console and select the server.
2. Open the Firewall tab.
3. Make sure Firewall is Enabled is checked.

In the server's Firewall tab, check Firewall is Enabled.

Recommended defaults:

• Input Policy: DROP, which blocks any incoming traffic you have not explicitly allowed.
• Output Policy: ACCEPT, which lets the server reach out freely.

Input Policy on DROP, Output Policy on ACCEPT.

How do you add a new rule?

Click the blue Add Rule button and fill in the fields. Here are the two most common examples.

Example 1: SSH (port 22) from your office only

• Direction: IN (incoming traffic).
• Interface: leave ANY.
• Protocol: TCP.
• Source: your office IP address, for example 203.0.113.5.
• Port: 22.
• Destination: leave empty.
• Policy: ACCEPT.
• Comment: add a note such as "SSH Access – My Office".

A rule that allows SSH on port 22 from the office IP only.

Example 2: RDP (terminal server) on port 3389

A terminal server (RDP) listens on port 3389 by default. To allow access only from one address or range:

• Direction: IN.
• Interface: ANY.
• Protocol: TCP.
• Source: a single IP (203.0.113.5) or a range (203.0.113.0/24).
• Port: 3389.
• Destination: leave empty.
• Policy: ACCEPT.
• Comment: for example "RDP Access – My Office".

How do you create an IP Set and an IP Alias?

IP Set: a reusable list of addresses

1. Click Add IP Set.
2. Name the list, for example "Allowed Offices".
3. Click Add Address and add every authorised IP (office, home and so on).
4. Save the list.

When you add a new rule, pick the list in the Source field instead of typing each address by hand.

A list of authorised addresses (IP Set) that any rule can use.

IP Alias: a friendly name for an address

An IP Alias gives a simple name to an address or range you use regularly. For example:

• Name: MainOffice.
• IP Address: your office address, for example 203.0.113.5.
• Comment: optional, for example "Main office address".

Aliases make new rules faster to add and the rule list easier to read.

What are the best practices?

• Allow (ACCEPT) only the ports your business actually needs.
• Block (DROP) all other traffic by default.
• Allow management access (SSH, RDP) only from a list of trusted addresses, never from the whole internet.
• Add a comment to every rule, so it is clear six months from now why it exists.

The rule list: each rule with its direction, protocol, source, port and comment.

Frequently asked questions

Does the firewall cost extra?

No. It is built into the OMC Cloud console and available on every server at no extra cost and with nothing to install.

What is the difference between DROP and ACCEPT?

ACCEPT lets matching traffic through. DROP blocks it silently, without replying to the sender.

What if I lock myself out?

If your IP address changes or a rule is deleted by mistake, you can fix the rules in the cloud console, which does not depend on the server's firewall. Our support team can help if needed.

Should I open RDP or SSH to the whole internet?

No. That is one of the most common ways to attract brute-force attacks. Allow access only from known addresses, ideally through an IP Set.

Conclusion

The free OMC Cloud firewall gives every cloud server solid protection at no extra cost: switch it on, block by default, and open only what is needed to only those who need it. IP Sets and Aliases keep the rules simple to manage. Need a hand with the setup? Our experts are always here to help.