I followed this thread and was able to get a good configuration of PIA OpenVPN with Merlin 380.65_2, however had noticed a number of things.
First, in speaking with PIA support, I inquired about the persist custom configurations and they provided the following detail:
The persist options ( persist-key persist-tun ) when used will try to avoid accessing certain resources on restart that may no longer be accessible because of the privilege downgrade. Such as when or if the VPN restarts, the client will keep the TUN/TAP interface open. When it renegotiates with the server, it will check that server is giving it the same virtual IP address as it gave before. If so, everything is good. If not,( i.e. the client detects that the new IP address given is different than the old, it will close and reopen the TUN/TAP interface.)
Further, I found that similar to Xentrk, AB-Solution only worked initially when
Accept DNS Configuration is set to Strict rather than Exclusive. However, when selecting Strict, I found that DNS was leaking from the ISP (
https://ipleak.net/ &
https://dnsleaktest.com). This appears to be due to the fact that I am using Policy Rules with the full /24 through VPN along with specific IP exceptions going through WAN. I believe that if I didn't have a requirement for Policy Rules, that the DNS leak might not occur.
As I consider AB-Solution a must and require Policy Rules, I opted to try getting DNSCrypt in place instead and followed the install at:
https://www.snbforums.com/threads/release-dnscrypt-installer-for-asuswrt.36071/ with good success. After installing DNSCrypt, DNS leak tests showed DNS from only OpenDNS (what I selected at install) rather than the local ISP. After clearing DNS cache and restarting the router, all clients reported OpenDNS, which I wasn't sure if was expected or if it should show as using PIA DNS for clients through the VPN. I decided to test and switched
Accept DNS Configuration back to Exclusive, gave the router a reboot, cleared client cache and found that DNS still shows as OpenDNS, but that AB-Solution also remained functioning (verified by following the log).
I am quite content to stick with
Accept DNS Configuration set to Exclusive, having a verified functioning PIA VPN (4096/256-bit AES encryption), working AB-Solution, and possibly OpenDNS showing as it is at least not leaking ISP DNS or using a transparent DNS proxy back to the ISP from what I can tell.
My question is whether it is expected that OpenDNS is used even when
Accept DNS Configuration is set to Exclusive or if I should be seeing the PIA VPN DNS instead? If it should show as PIA VPN, any thoughts what might be configured incorrectly?
Two other points, I believe that in Merlin 380.65_2,
Cipher Negotiation must be set to Enable (with fallback) and the
Negotiation ciphers and
Legacy/fallback cipher both need to be set to the desired cipher (AES-256-CBC in my case) or the cipher validation fails and the VPN will not pass traffic. This appears as TUN/TAP write bytes not increasing past 0 on the VPN Status page. Lastly, in my case, I did not see a performance increase when using 2048/128-bit AES encryption using an AC68 router; both 128 and 256 measured at around 25Mbps down and about 50Mbps down with no VPN on the same wireless from the remote location I'm at.