Tag: linux

How to setup a Socks5 Proxy server on Ubuntu 16.04 with Dante

nano /etc/danted.conf
# /etc/danted.conf

logoutput: syslog
user.privileged: root
user.unprivileged: nobody

# The listening network interface or address.
internal: 0.0.0.0 port=1080

# The proxying network interface or address.
external: eth0

# socks-rules determine what is proxied through the external interface.
# The default of "none" permits anonymous access.
socksmethod: username

# client-rules determine who can connect to the internal interface.
# The default of "none" permits anonymous access.
clientmethod: none

client pass {
        from: 0.0.0.0/0 to: 0.0.0.0/0
        log: connect disconnect error
}

socks pass {
        from: 0.0.0.0/0 to: 0.0.0.0/0
        log: connect disconnect error
}

References
http://www.binarytides.com/setup-dante-socks5-server-on-ubuntu/

Hide OpenVPN traffic using Obfsproxy on Ubuntu16.04

sudo pip install obfsproxy
obfsproxy --log-min-severity=info obfs2 --dest=127.0.0.1:1194 --shared-secret=<some-random-key> server 0.0.0.0:8080

References
https://www.comparitech.com/blog/vpn-privacy/hide-openvpn-traffic-obfsproxy-on-windows-and-linux-ec2/
https://community.openvpn.net/openvpn/wiki/TrafficObfuscation
https://sourceforge.net/p/openvpn/mailman/message/28851866/
https://dlshad.net/bypassing-censorship-by-using-obfsproxy-and-openvpn-ssh-tunnel/

How To List and Delete Iptables Firewall Rules on Ubuntu 16.04

List Rules by Specification

sudo iptables -S

List Rules as Tables

sudo iptables -L

Delete Rule by Specification

sudo iptables -D INPUT -m conntrack --ctstate INVALID -j DROP

Delete Rule by Chain and Number

sudo iptables -L --line-numbers
sudo iptables -D INPUT 3

Flush All Rules, Delete All Chains, and Accept All
Note: This will effectively disable your firewall. You should only follow this section if you want to start over the configuration of your firewall.

sudo iptables -P INPUT ACCEPT
sudo iptables -P FORWARD ACCEPT
sudo iptables -P OUTPUT ACCEPT
sudo iptables -t nat -F
sudo iptables -t mangle -F
sudo iptables -F
sudo iptables -X

References
https://www.digitalocean.com/community/tutorials/how-to-list-and-delete-iptables-firewall-rules

OpenVPN software repository for Ubuntu 16.04

sudo -s
wget -O - https://swupdate.openvpn.net/repos/repo-public.gpg|apt-key add -
echo "deb http://build.openvpn.net/debian/openvpn/<version> <osrelease> main" > /etc/apt/sources.list.d/openvpn-aptrepo.list
echo "deb http://build.openvpn.net/debian/openvpn/stable xenial main" > /etc/apt/sources.list.d/openvpn-aptrepo.list
apt-get update && apt-get install openvpn

References
https://community.openvpn.net/openvpn/wiki/OpenvpnSoftwareRepos

Maximum simultaneous connections on a mosquitto broker

nano /etc/sysctl.conf
fs.file-max = 999999
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.ipv4.tcp_rmem = 4096 4096 16777216
net.ipv4.tcp_wmem = 4096 4096 16777216
net.ipv4.tcp_syncookies = 1
# this gives the kernel more memory for tcp
# which you need with many (100k+) open socket connections
net.ipv4.tcp_mem = 50576   64768   98152
net.core.netdev_max_backlog = 2500
nano /etc/security/limits.conf
*       soft    nofile  262144
*       hard    nofile  262144
*       soft    nproc  262144
*       hard    nproc  262144
cat /proc/sys/net/ipv4/ip_local_port_range
cat /proc/sys/kernel/threads-max
nano .bashrc
ulimit -t unlimited
ulimit -c unlimited
ulimit -a

References
https://lists.launchpad.net/mosquitto-users/msg00163.html