Automatically set up an Openconnect VPN server(ocserv) with Let's Encrypt with just one command.

• Secured with a valid certificate from Let's encrypt
• No IP Leak
• No DNS Leak
• No request/send from/to external/third party sources

All you need: A CentOS 8 server with a domain.

Note 05/09/2021: If you had any problem, disable UDP and do not use the Anyconnect client app for a while!

Note 23/09/2021: Change the server or server IP every 3 months to prevent Google from tracking and flagging your server's IP.

Install, configure, run with one command:

Change the username-password list pass.txt (or create a new one) and then just run the command like this :

bash install.sh -f username-list-file -n host-name -e email-address

for example :

bash install.sh -f pass.txt -n my.example.com -e [email protected]

Note: By changing the script, you can get a certificate without an email address. But it is better not to. (--email $EMAIL_ADDR to --register-unsafely-without-email)

If you want to add a list of users again after installation:

bash adduser.sh username-list-file

e.g. :
bash adduser.sh pass2.text

Renew the certificate before/after 3 months:

certbot renew --quiet && systemctl restart ocserv # && systemctl restart ocserv2

Run two copies of ocserv on the same server

Do you want to run ocserv on a new port with a different configuration? Take a look at copyoc.sh.

New ocserv copy

 bash ./copyoc.sh -p <port>

e.g. :
bash ./copyoc.sh -p 8443

New ocserv copy for families (Cloudflare DNS for families)

Will block malware and adult content in the new VPN service

 bash ./copyoc.sh -p <port> -f
 
 e.g. :
 bash ./copyoc.sh -p 2222 -f

Bypass the Internet blackout

(reference: https://ooni.org/post/2019-iran-internet-blackout/#connecting-to-the-internet-from-iran)

After installing Openconnect on a foreign VPS, just enter these commands on the domestic VPS:

echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A PREROUTING -i eth0 -p tcp -m tcp --dport 443 -j DNAT  --to-destination [foreignVPSip]:443
iptables -t nat -A PREROUTING -i eth0 -p udp -m udp --dport 443 -j DNAT  --to-destination [foreignVPSip]:443
iptables -t nat -A PREROUTING -i eth0 -p udp -m udp --dport 53 -j DNAT  --to-destination [foreignVPSip]:53
iptables -t nat -A POSTROUTING -o eth0 -j SNAT --to-source [domesticVPSip]

(Note: Make sure you use the correct network interface name. e.g. eth0 or enp0s3 or ... )

Then save iptables:

yum install iptables-services -y

systemctl enable iptables

service iptables save

systemctl start iptables

And then use Openconnect like this:

echo password|openconnect --resolve=domain.com:[domesticVPSip] -vu username --passwd-on-stdin https://domain.com

Or temporary change A record to domestic VPS ip.

Note: The amount of incoming and outgoing traffic on your domestic VPS should not be equal.

Please let me know if there is any problem.