As the VPN server, Vigor Router always listens to the VPN ports for accepting VPN connection from on the internet. Sometimes, we may see some unknown IP addresses keep sending VPN request to Vigor Router on Syslog, but cannot find out who the remote peer is. It is annoying and might be a security risk. This document will demonstrate how to block the unknown IP address which keeps dialing VPN to Vigor Router.
Since firmware 4.4.0, Vigor Router supports the local filter that can be applied for Vigor Router itself. With the local filter, we can block some unknown IP addresses which keep dialing the VPN or keep trying to access the router with the HTTP protocol. Moreover, we can also block IPs from specified countries to prevent the attack by the IP from a specified country. In this article, we demonstrate some practical applications for the local filter.
Select log if you want to see from Syslog Explorer.
Input the unknown peer's IP and click Add to add the IP into Black IP List.
|The Source IP supports 4 options to define IP properties.
|IP can input single IP address.
|IP Object can apply to object profile defined in Objects Setting >> IP Object in advance.
|IP Group can apply to group object profile defined in Objects Setting >> IP Group in advance.
|Country Object can only apply to object profile defined in Objects Setting >> Country Object in advance.
In the Syslog, we will receive an alert from the router when the IP in blacklist attempt to access.
|Different service uses different service port
|PPTP -> TCP 1723, GRE(protocol 47)
|L2TP -> TCP 1701, UDP 500/4500
|IPsec -> UDP 500/4500, ESP(protocol 50)
|SSL -> TCP 443
|OpenVPN -> TCP 443/1194, UDP 1194
Vigor Router supports VPN server options in Brute Force Protection which enables users to deny VPN account login attempts from brute-force attack.
To learn how to use Syslog Utility to collect the syslog, please refer to the article Collecting router's Syslog
Note: DrayTek Routers includes GeoLite2 data created by MaxMind, available from https://www.maxmind.com.
1. Go to Objects Setting >> IP Object page and add the unknown IP as an IP Address.
2. Go to Objects Setting >> Time Object page and add a Time Object.
Note: Please enter the Start Time which is later but closed to the current time, and the End Time is a little earlier than the Start Time. For example, if the current time is 15:55 and we can enter the start time as 16:00:00, and the end time as 15:59:59. After the firewall rule effects, this Time Object can be removed.
3. Go to Firewall >> Filter Setup page, create an IP Filter Group then click Add to create an IP Filter Rule for blocking the unknown peer IP.
After that, we will see such kind of Firewall log instead of the VPN log:
<13>Dec 27 17:13:02 Vigor: [Clear Session] Delete conntrack by ip_filter_set_rule : unknown
<135>Dec 27 17:13:07 Vigor: [IPF-unknown] BLOCK src ip 188.8.131.52 mac 00:1d:aa:xx:xx:xx dst ip 172.17.5.92 proto udp DPT=500, skbmark=10000002/0
Published On: 2019-07-08
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