Or, if you want to filter it by the IP address of your VPN client (adjust as needed): tcpdump -eni any port 53 | grep "172.27.10.22" With TCPdump installed, now run it with these parameters: tcpdump -eni any port 53
#Pritunl docker update#
On the Access Server run these commands: apt-get update If you are testing on a production system and the tcpdump command gives too much output, you can append a grep filter by IP address, to filter queries coming only from your specific VPN client's IP address, to make reading and locating the DNS query results easier. In our test situation, there are only a handful of clients connected, and the activity of DNS queries is very low, so we can monitor it easily. We will be flushing the local DNS resolver cache on the client side, and then resolve a number of domains simply by pinging them by name. We will be using the tool tcpdump to monitor activity on port 53 TCP and UDP, the default port where DNS queries are handled. Next open a console session or an SSH session to the OpenVPN Access Server, and obtain root privileges.
#Pritunl docker windows 10#
In our example we will be using a Windows 10 Professional client system with the OpenVPN Connect Client installed, and connected to the OpenVPN Access Server.
#Pritunl docker install#
Install your OpenVPN client program on your chosen client system. In our example we are pushing the Google Public DNS server 8.8.8.8, and our test results will reflect this in the sample outputs as well. With this setting, all DNS request should be going from the OpenVPN client, through the OpenVPN Access Server, and then to the specified DNS server. We are assuming you are not using the DNS Resolution Zones or the DNS Default Suffix fields. We are going to assume that you have a DNS server configured in the Admin UI of the Access Server, under VPN Settings. Testing DNS resolution from a client system This information is valuable in determining whether or not the problem is at the client end, or at the server end. And from there, of course, to the target DNS server. The guide below provides a way of checking to see if the DNS query you are doing from your OpenVPN client device, is actually making it through the VPN tunnel to the OpenVPN Access Server. Others will be able to do split-DNS, and others will not. Some systems will try all DNS servers at once, and accept the response from the first to respond. Unfortunately, not every operating system behaves the same in regards to DNS. The Access Server also supports sending additional instructions for DNS Resolution Zones, which functions like a type of split-DNS where only queries for a specific DNS zone are sent to the VPN server, and DNS Default Suffix, which provides a hint to Windows to 'autocomplete' a partial hostname to a Fully Qualified Domain Name, or FQDN. This can be configured in the Admin UI under VPN Settings. Actually it supports pushing 2 DNS servers, in case the first one fails to respond. OpenVPN Access Server supports pushing an instruction to a connecting OpenVPN client to use a specific DNS server. It is for example easier to tell a user to start their Remote Desktop client program and to connect to server1 instead of having to tell them to connect to 192.168.70.243. Companies often run their own DNS server that they use to resolve DNS names to private IP addresses, to make accessing systems easier for users.
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