IPBan blocked access to the server: how to unblock the cashier's IP address

IPBan is a server-side security utility that automatically blocks IP addresses when unauthorized access is suspected (frequent password errors, mass login attempts, brute-force).

This article explains how to identify an IPBan block and restore the cash register’s access to the server.

When to check IPBan

• The cash register suddenly cannot connect to the server.

• The server is working, but access is unavailable from only one workstation.

• The problem appeared after several failed RDP login attempts.

Signs of the problem

• Selective access:
  Connection from the cash register is impossible, but it works from other PCs or for technical support.

• RDP error / timeout:
  Remote Desktop does not connect, although the cash register has Internet access.
  If you temporarily connect the PC to another network (for example, for testing), the RDP connection may:

• also fail to appear (the problem is not related to the current network), or
• be restored (likely RDP blocking on the side of the current network/provider; in this case, the IP of this network may be absent from the IPBan Blacklist).

• IP in Blacklist:
  In the IPBan interface on the server, the store’s IP address is present in the list of blocked addresses.

Possible causes

1. Repeated entry of an incorrect password for the server (RDP).

2. Frequent connection attempts in a short period of time, which the system treats as an attack.

3. A dynamic IP address from the provider (the address may have been blocked earlier).

4. Suspicious traffic from the cash register PC (malware or incorrect network settings).

What to do

 Unblocking is possible only with server access under an administrator account.
If all access is blocked, assistance from another employee or technical support is required.

Step 1. Check the Blacklist

1. Log in to the server as an administrator.

2. Open IPBanGUI / IPBanUI.

3. Go to the Blacklist section (Blocked IPs).

4. Find the cash register’s IP address (the store’s external IP).

Step 2. Unblock the IP

1. Select the IP address in the list.

2. Click Remove / Unblock.

3. Confirm the action.

Step 3. Add the IP to the Whitelist (mandatory)

1. Go to the Whitelist tab.

2. Add the store’s static IP address.

3. Save the changes.

 Without adding it to the Whitelist, the block may happen again.

Step 4. Check the connection

1. Repeat the RDP connection from the cash register PC.

2. A login/password prompt should appear.

3. The connection is established without an error.

How to check the result

• The RDP connection from the cash register is successful.

• The IP address is absent from the IPBan Blacklist.

• There are no new blocks for this address in the IPBan logs.

How to avoid the problem

• Use a static external IP address at the retail location.

• Add all known store IPs to the IPBan Whitelist in advance.

• Avoid manual password entry (configure saved access).

• Make sure staff do not repeatedly try to guess the password.

Summary

If the server is accessible from other PCs, but the cash register does not connect →
check the IPBan Blacklist → unblock the IP → add it to the Whitelist.