Firewall INPUT filters

INPUT view

Basic inputs

You can find the basics INPUT rules over here: Firewall core (main) protocols

Security services

SSH

# SSH - max 3 connection request per minute
$IPTABLES -A INPUT -p tcp -m limit 3/min --limit-burst 3 --dport 22 -j ACCEPT

LDAP

$IPTABLES -A INPUT -p tcp -m state --state NEW --dport 389 -j ACCEPT # LDAP
$IPTABLES -A INPUT -p tcp -m state --state NEW --dport 636 -j ACCEPT # LDAPS

Web services

Recommendation: you should only open HTTP and HTTPS (TCP 80 +443) + use some proxy redirections. see: Sonar#Apache2 proxy

HTTP web server

You have to open the following ports:

• Port 80 = HTTP
• Port 443 = HTTPS

$IPTABLES -A INPUT -p tcp -m state --dport 80 -j ACCEPT
$IPTABLES -A INPUT -p tcp -m state --dport 443 -j ACCEPT

Application servers (HTTP alt.)

You have to open the following ports:

• Port 8080 = HTTP alt.
• Port 8443 = HTTPS alt.

$IPTABLES -A INPUT -p tcp -m state --dport 8080 -j ACCEPT
$IPTABLES -A INPUT -p tcp -m state --dport 8443 -j ACCEPT

Sometimes you can also use:

# JBoss wildfly 
$IPTABLES -A INPUT -p tcp --dport 9990 -j ACCEPT   # Wildfly administration
# Glassfish
$IPTABLES -A INPUT -p tcp --dport 4848 -j ACCEPT   # Glassfish4 administration manager
$IPTABLES -A INPUT -p tcp --dport 1527 -j ACCEPT   # Glassfish4 security manager
$IPTABLES -A INPUT -p tcp --dport 7676 -j ACCEPT   # Open MQ (bundled with Glassfish) - JMS broker

Sonar

You have to open the port 9000

$IPTABLES -A INPUT -p tcp -m state -i eth0 --dport 9000 -j ACCEPT

Zabbix

You have to open the port 10051

$IPTABLES -A INPUT -p tcp -m state --dport 10051 -j ACCEPT

Webmin

You have to open the port 10000 at last.

$IPTABLES -A INPUT -p tcp -m state --dport 10000 -j ACCEPT   # Webmin services manager
$IPTABLES -A INPUT -p tcp -m state --dport 20000 -j ACCEPT   # Webmin users management

DHCP

This is how you enable a DHCP server with TFTP (netBoot) :

IPTABLES=`which iptables`
LAN_ADDRESS="172.16.50.0/24"

# Allow LAN communication
# ... Required for NFS and the NetBoot ...
$IPTABLES -A INPUT -s $LAN_ADDRESS -d $LAN_ADDRESS -m state ! --state INVALID -j ACCEPT
$IPTABLES -A OUTPUT -s $LAN_ADDRESS -d $LAN_ADDRESS -m state ! --state INVALID -j ACCEPT
 
########################
# INPUT filters
########################
 
##### DHCP client ######
# Broadcast IP request 
$IPTABLES -A OUTPUT -p udp -d 255.255.255.255 --sport 68 --dport 67 -j ACCEPT
# Send / reply to IPs requests
$IPTABLES -A INPUT -p udp -s 255.255.255.255 --sport 67 --dport 68 -j ACCEPT
 
###### DHCP server ######
# Received client's requests [udp + tcp]
$IPTABLES -A INPUT -p udp --sport 68 --dport 67 -j ACCEPT
$IPTABLES -A INPUT -p tcp --sport 68 --dport 67 -j ACCEPT

# NetBoot - TFTP server
$IPTABLES -A INPUT -p udp -s $LAN_ADDRESS --dport 69 -j ACCEPT
 
 
########################
# OUTPUT filters
########################
# DHCP [udp + tcp]
$IPTABLES -A OUTPUT -p udp --dport 67 -j ACCEPT
$IPTABLES -A OUTPUT -p tcp --dport 67 -j ACCEPT
$IPTABLES -A OUTPUT -p udp --dport 68 -j ACCEPT
$IPTABLES -A OUTPUT -p tcp --dport 68 -j ACCEPT
 
# TFTP NetBoot 
$IPTABLES -A OUTPUT -p udp --dport 69 -j ACCEPT

Note the difference between the broadcast request that every computer should allow and the plain OUTPUT allow on ports 67,68 for the DHCP server !!

Don't forget to adjust your network number 172.16.50.0/24

NFS

It's really tricky to adjust the firewall for NFS as the port is dynamic. But option is to allow LAN traffic and use NFS over LAN only.