Download, import and update firewall address-lists

ℹ️ Info: This script can not be used on its own but requires the base installation. See main README for details.

Description

This script downloads, imports and updates firewall address-lists. Its main purpose is to block attacking ip addresses, spam hosts, command-and-control servers and similar malicious entities. The default configuration contains a list from dshield.org.

The address-lists are updated in place, so after initial import you will not see situation when the lists are not populated.

To mitigate man-in-the-middle attacks with altered lists the server's certificate is checked.

Requirements and installation

Just install the script:

$ScriptInstallUpdate fw-addr-lists;

And add two schedulers, first one for initial import after startup, second one for subsequent updates:

/system/scheduler/add name="fw-addr-lists@startup" start-time=startup on-event="/system/script/run fw-addr-lists;";
/system/scheduler/add name="fw-addr-lists" start-time=startup interval=2h on-event="/system/script/run fw-addr-lists;";

ℹ️ Info: Modify the interval to your needs, but it is recommended to use less than half of the configured timeout for expiration.

Configuration

The configuration goes to global-config-overlay, these are the parameters:

FwAddrLists: a list of firewall address-lists to download and import
FwAddrListTimeOut: the timeout for expiration without renew

ℹ️ Info: Copy relevant configuration from global-config (the one without -overlay) to your local global-config-overlay and modify it to your specific needs.

Naming a certificate for a list makes the script verify the server certificate, so you should add that if possible. Some certificates are available in my repository and downloaded automatically. Import it manually (menu /certificate/) if missing.

Create firewall rules to process the packets that are related to addresses from address-lists. This rejects the packets from and to ip addresses listed in address-list block.

/ip/firewall/filter/add chain=input src-address-list=block action=reject reject-with=icmp-admin-prohibited;
/ip/firewall/filter/add chain=forward src-address-list=block action=reject reject-with=icmp-admin-prohibited;
/ip/firewall/filter/add chain=forward dst-address-list=block action=reject reject-with=icmp-admin-prohibited;
/ip/firewall/filter/add chain=output dst-address-list=block action=reject reject-with=icmp-admin-prohibited;

You may want to have an address-list to allow specific addresses, as prepared with a list allow. In fact you can use any list name, just change the default ones or add your own - matching in configuration and firewall rules.

/ip/firewall/filter/add chain=input src-address-list=allow action=accept;
/ip/firewall/filter/add chain=forward src-address-list=allow action=accept;
/ip/firewall/filter/add chain=forward dst-address-list=allow action=accept;
/ip/firewall/filter/add chain=output dst-address-list=allow action=accept;

Modify these for your needs, but most important: Move the rules up in chains and make sure they actually take effect as expected!

Alternatively handle the packets in firewall's raw section if you prefer:

/ip/firewall/raw/add chain=prerouting src-address-list=block action=drop;
/ip/firewall/raw/add chain=prerouting dst-address-list=block action=drop;
/ip/firewall/raw/add chain=output dst-address-list=block action=drop;

⚠️ Warning: Just again... The order of firewall rules is important. Make sure they actually take effect as expected!

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