# Iptables

Iptables are used in the Debian install script.

## Basic Rules
```
iptables -A INPUT -i lo -j ACCEPT`
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A INPUT -p tcp --dport 22 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j ACCEPT
iptables -A INPUT -p tcp --dport 5060:5069 -j ACCEPT
iptables -A INPUT -p udp --dport 5060:5069 -j ACCEPT
iptables -A INPUT -p tcp --dport 5080 -j ACCEPT
iptables -A INPUT -p udp --dport 5080 -j ACCEPT
iptables -A INPUT -p udp --dport 16384:32768 -j ACCEPT
iptables -A INPUT -p icmp --icmp-type echo-request -j ACCEPT
iptables -A INPUT -p udp --dport 1194 -j ACCEPT
iptables -P INPUT DROP
iptables -P FORWARD DROP
iptables -P OUTPUT ACCEPT
```

## Optional Rules

OPENVPN
```
iptables -A INPUT -p udp --dport 1194 -j ACCEPT
```

ICMP
```
iptables -A INPUT -p icmp --icmp-type echo-request -j ACCEPT
```

## Friendly Scanner

Rules to block not so friendly scanner
```
iptables -I INPUT -j DROP -p tcp --dport 5060 -m string --string "friendly-scanner" --algo bm
iptables -I INPUT -j DROP -p tcp --dport 5080 -m string --string "friendly-scanner" --algo bm
iptables -I INPUT -j DROP -p udp --dport 5060 -m string --string "friendly-scanner" --algo bm
iptables -I INPUT -j DROP -p udp --dport 5080 -m string --string "friendly-scanner" --algo bm
```

**Optional**
```
iptables -I INPUT -j DROP -p tcp --dport 5060 -m string --string "VaxSIPUserAgent" --algo bm
iptables -I INPUT -j DROP -p udp --dport 5060 -m string --string "VaxIPUserAgent" --algo bm
iptables -I INPUT -j DROP -p udp --dport 5080 -m string --string "VaxSIPUserAgent" --algo bm
iptables -I INPUT -j DROP -p tcp --dport 5080 -m string --string "VaxIPUserAgent" --algo bm

iptables -I INPUT -j DROP -p tcp --dport 5060 -m string --string "VaxSIPUserAgent/3.1" --algo bm
iptables -I INPUT -j DROP -p udp --dport 5060 -m string --string "VaxSIPUserAgent/3.1" --algo bm
iptables -I INPUT -j DROP -p udp --dport 5080 -m string --string "VaxSIPUserAgent/3.1" --algo bm
iptables -I INPUT -j DROP -p tcp --dport 5080 -m string --string "VaxSIPUserAgent/3.1" --algo bm
```

## Add DSCP rules
```
iptables -t mangle -A OUTPUT -p udp -m udp --sport 16384:32768 -j DSCP --set-dscp 46 
iptables -t mangle -A OUTPUT -p udp -m udp --sport 5060:5091 -j DSCP --set-dscp 26 
iptables -t mangle -A OUTPUT -p tcp -m tcp --sport 5060:5091 -j DSCP --set-dscp 26
```

## Show iptable rules

```
sudo iptables -L -v
```

## Show line numbers

```
iptables -L -v -n --line-numbers
```

## Show DSCP rules
```
iptables -vL -t mangle
```

## Delete a line

Delete line 2

```
iptables -D INPUT 2
```

## Flush Out Iptables
```
iptables -P INPUT ACCEPT
iptables -P FORWARD ACCEPT
iptables -P OUTPUT ACCEPT
iptables -F
```
## Open a Port for a Specific IP Address

```
iptables -A INPUT -j ACCEPT -p tcp --dport 5432 -s x.x.x.x/32
```

## Block IP address

```
iptables -I INPUT -s 62.210.245.132 -j DROP
```

## Restore Rules from rules.v4

This reads the file rules.v4 and saved iptables rules back into active
memory.
```
iptables-restore < /etc/iptables/rules.v4
```

## Flush iptables

How to flush iptables without loosing access to ssh.
```
iptables -P INPUT ACCEPT
iptables -F
```

## Save Changes

Debian / Ubuntu
```
apt-get install iptables-persistent
service iptables-persistent save
dpkg-reconfigure iptables-persistent
iptables-save > /etc/iptables/rules.v4
ip6tables-save > /etc/iptables/rules.v6
```