Q: cant connect socks proxy server on cent os I Install ss5 or 3proxy on cent os (VPS).I Check port 1080 with port checker online and get port 1080 is open but when I try to connect to proxy server I cant connect.
firewalld is removed.
SERVER ram 512MB .CPU 1 CORE 1400 MHZ

A: First of all disable selinux
sudo setenforce 0

However, this change will be valid for the current runtime session only.
to disable for good 
vi /etc/selinux/config

and change SELINUX=disabled so this will make it permanent. 
 Save the file and reboot your CentOS system with sudo shutdown -r now
 After reboot verify the selinux status with sestatus your status should be SELinux status:                 disabled
Second make sure that your 3proxy.cfg - config should look something like this: 
 # use global nameserver using google DNS here
nserver 8.8.8.8
nserver 8.8.8.4

# options
daemon
nscache 65536
timeouts 1 5 10 30 180 1800 15 60

# authentication mode, you can auth with username and password or from an IP address, see below
auth iponly strong

# users list - here if you want to login with username and password
users "username:CL:password"

# ip allow list —— if you want to login from an IP address
allow * 82.224.29.140 * *

# Must be the same with the username you have in the userlist
allow username * * *

# Number of maximum connections 100 is more then enough
maxconn 100

# proxy - here you create the socks -p is the port -i the local IP address(the ip you should connect to) and -e is the exit IP address, in case you have more then 1 IP on the server 
socks -a -p51365 -i172.22.33.11 -e172.22.33.11

# another example with another exit IP address if you have more then 1 ip addresses on the vps
socks -a -p51365 -i172.22.33.11 -e172.33.44.44

# feel free to remove the lines with # since they are just comments so you can understand what you are doing and if you have only 1 IP address remove the last example also

