Advanced Blocking Settings
Advanced Blocking Settings Overview
Starting from version 3.1.7 RdpGuard supports advanced blocking settings providing you the way
to define how attackers' IP addresses are blocked.
Earlier versions of RdpGuard block all access to the server when the number of failed login attempts from
a single IP address reaches a set limit.
In some cases you may want to block only particular ports, for example RDP, FTP, SMTP
while leaving others accessible, for example HTTP or HTTPS.
This can be configured via Advanced Blocking Settings.
How to configure Advanced Blocking Settings
1. Click Tools, Options
Click Tools, Options
The Options dialog will open:
RdpGuard Options dialog
2. Click Advanced blocking settings..
The Advanced blocking settings dialog will open:
How to block access to all ports
3.a. If you would like to block access to all ports on your server (i.e. make your server invisible to the attacker),
tick the Block access to all ports on the server checkbox and click Save
3.b. If you would like to block access only to particular protocols, untick the Block access to all ports on the server
checkbox and specify the ports you want to block when the number of failed logon attempts reaches a set limit.
How to block only particular ports
4. Click Save
Performance Considerations
Things to consider when blocking multiple custom ports: if you would like to block multiple ports
like shown on the screenshot above, please note that this will increase the number of conditions added to the
Windows Filtering Platform proportionally and may affect network (and overall) performance.
When you block all access to the server (the Block access to all ports on the server checkbox ticked)
- one condition is required to block one IP address.
But everything changes when you block specific ports, like 3389, 21, 25, 110. The number of conditions added to
Windows Filtering Platform increases proportionally:
Conditions per one IP = Number of Ports [TCP] + Number of Ports [UDP]
For example, blocking 1000 IP addresses from accessing all ports on a server requires 1000 conditions
in the Windows Filtering Platform.
When you block access for the same 1000 IP addresses to 4 ports (for example, 3389, 21, 25, 110)
- 8000 conditions are added to the Windows Filtering Platform (4 for TCP and 4 for UDP), which can have
a greater impact on network performance.
The number of conditions added in the Windows Filtering Platform affects the network (and overall) performance of your server,
so we recommend leaving the Block access to all ports on the server option enabled and the default blocking period of 24 hours
to reduce the number of blocking conditions.
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