****Please take note there was an error for port 1198
I forgot to put disable-occ in custom configurations.
Please fix this otherwise the following 2 warnings will show up in system log
WARNING: 'link-mtu' is used inconsistently, local='link-mtu 1558', remote='link-mtu 1542'
WARNING: 'cipher' is used inconsistently, local='cipher AES-128-CBC', remote='cipher BF-CBC'
PART I
Here is a how to guide using PIA VPN provider as an example which will help you in getting your VPN client up and running with Merlin Firmware.
I have updated this article to use PIA's new 1197 and 1198 ports with new certificates
If you do not use PIA read the section where I explain how to connect using other VPN providers
Please read both sections of this article carefully.
AES-128-CBC port 1198
View attachment 7395
AES-256-CBC port 1197
View attachment 7146
Custom configurations to use with PIA.
AES-128
View attachment 6800
AES-256
View attachment 6800
In "custom configurations" I have added the following
ns-cert-type server This will block clients from connecting to any server which lacks the
nsCertTyp
auth-nocache this command doesn't cache the password otherwise you may have a security issue.
mute-replay-warnings this command stops the same warning from appearing over and over in system log
***Please take note that this function was not indicated in previous article. You need to put
disable-occ in custom configurations for 1198 and 1197
It is important to add this line otherwise the following 2 warnings that will occur
WARNING: 'link-mtu' is used inconsistently, local='link-mtu 1558', remote='link-mtu 1542'
WARNING: 'cipher' is used inconsistently, local='cipher AES-128-CBC', remote='cipher BF-CBC'
By putting disable-occ on custom configuration for port 1197 and 1198 these warnings will disappear. I apologize for any inconveniences I may have caused with this error.
***Certificates for PIA and other providers are discussed in the next section of this article.
The VPN's speed will be determined by the encryption method you choose.
Dual core CPU's are the best choice because they deliver fastest speeds when in VPN client mode. Encryption makes the router work harder therefore
Models such as ASUS 68U or higher are the best choices.
Models such as ASUS 66U or inferior are not a great choice because they will give you slower speeds because they have a single core cpu and not as powerful as higher end models.
If VPN client or server is important to you, then think of upgrading to a better router.
UDP ports for PIA:
port 1194: This port uses Blowfish-CBC encryption and Auth digest to SHA1
No longer supported by PIA but you are free to try it
Speed: 30-35 mb/s
port 1195: For no encryption use with encryption type set to none and Auth digest set to none and in custom configuration add auth none. this method is the fastest and full speed but without encryption. Not very safe.
Speed: full bandwidth of your ISP
port 1197: For stronger encryption use with AES-256-CBC encryption and Auth digest sha256 speeds 20-30 mb/s
port 1198: Use the preferred encryption method which is AES-128-CBC encryption with Auth digest to SHA1
This encrytpion method delivers the fastest speeds compared to the other methods.
Speeds 50-60 mb/s
**certificates are discussed in Part II of the guide
TCP Ports:
PIA also offers TCP protocol on ports 501 AES-256-CBC and 502 AES-128-CBC
Configure the same as UDP Protocol with the exception of changing UDP to TCP and new port numbers. This TCP protocol has different certificates which are found in PART II of this article.
***Please refer to your VPN provider for encryption and ports
If you don't use PIA for your VPN provider the image above may not help you connect.
the easiest way to get your VPN client to work quickly and painlessly is to do the following.
Every provider will supply a .ovpn file. Simply click on the browse button in the "Import .ovpn file" and go to the location where you stored the .opvn file, select the .opvn file and then click upload. The router will read all the information from the .ovpn file and will then configure the VPN client. After the router has configures the client, Some VPN providers provide the certificates in the .ovpn file while some will have a separate .crt file. Make sure you copy and paste the certificates if they are not included in the .ovpn to the "Content modification of Keys & Certificates." area. If the .ovpn file has the certificates included you will see them copied into the "Content modification of Keys & Certificates." if not, you will have to do this manually.
Almost all providers will enter different data in the custom configurations area so do not be alarmed if the data is not the same or similar to PIA. The .ovpn file contains all the important information needed to auto configure the VPN client.
The same example above will work with Stock ASUS firmware
import the client.ovpn into another ASUS router. It will automatically configure everything you need to connect to the VPN Server, including certificates.
Simply go to the VPN client on your ASUS router and look for "Import .ovpn file" use the browse button to find the client1.ovpn file then click on upload.
That's it. you should be ready to connect. Turn the service state button to ON
You can enable start to WAN option if you want the Client to automatically connect to the VPN server when router gets rebooted.
Auth digest: refer to your VPN provider or leave it default if you are not sure.
Accept DNS Configuration should be set to exclusive
Encryption cipher: refer to your VPN provider or leave it default if you are not sure.
Use "POLICY RULES" in "Redirect Internet traffic" for selective routing
By enabling Policy rules feature, it gives you the freedom to route specific devices to VPN and other devices to Local ISP. You can even have a device use VPN but have specific address's use Local ISP or vise versa.
Please note:
When you are in a VPN tunnel the DNS is determined by the VPN therefore if you redirect specific IP address's to WAN which is Local ISP the DNS will show that of the VPN and not from Local ISP this is also known as a DNS leak.
However you can route your FTP or SMPT which do not use DNS therefore you can setup that all traffic goes to VPN except for FTP and SMPT so you can get your email or access your FTP without having it routed via the VPN.
When you enable Policy Rules you have an extra option "block traffic if VPN goes down".
This is one of the best features when using Merlin firmware because when it's enabled if for some reason the VPN Server drops connection the router will suspend all traffic until the VPN client re connects to the server. This way you won't leak your Local IP address to the public.
Please refer to the second part of this article for examples using Policy Rules.
Enable the feature "Redirect Internet traffic" to to "ALL Traffic" if you want all your devices to go through the VPN tunnel which will exclusively use the DNS of VPN
set to compression "none" Do Not disable compression because the VPN tunnel won't work.
compression is not needed because, jpg, mp3, mp4, smart phone etc are all compressed data.
Here is a good chart you can bookmark for ports and certificates from PIA;
https://helpdesk.privateinternetacc...ings-should-I-use-for-ports-on-your-gateways-
Part II follows;