Linux Redhat - when the network comes up it will try to execute all of the ifcfg* files in ### etc/sysconfig/network-scripts so create a new file ifcfg-eth01 for arguments sake and add:
### /etc/sysconfig/network-scripts/ifcfg-eth0:1
DEVICE=eth0:1
BOOTPROTO=static
IPADDR=192.168.0.1
NETMASK=255.255.255.0
NETWORK=192.168.0.0
BROADCAST=192.168.0.255
ONBOOT=yes
to add a virtual ip from the command line simply type:
ifconfig eth0:1 192.168.0.1 255.255.255.0
then add:
route add default gw 192.168.0.50 (GATEWAY)
to make make the machine publically visible to through the firewall
Gateway settings
reside in ### /etc/sysconfig/network
NETWORKING=yes
NETWORKING_IPV6=no
HOSTNAME=myServerBox
GATEWAY=192.168.0.1
DNS settings
reside in /etc/resolv.conf
nameserver 192.168.1.1
nameserver 192.168.1.2
Firewall Settings (IPTables)
reside here:### etc/sysconfig/iptables
# Firewall configuration written by system-config-securitylevel
# Manual customization of this file is not recommended.
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:RH-Firewall-1-INPUT - [0:0]
-A INPUT -j RH-Firewall-1-INPUT
-A FORWARD -j RH-Firewall-1-INPUT
-A RH-Firewall-1-INPUT -i lo -j ACCEPT
-A RH-Firewall-1-INPUT -p icmp --icmp-type any -j ACCEPT
-A RH-Firewall-1-INPUT -p 50 -j ACCEPT
-A RH-Firewall-1-INPUT -p 51 -j ACCEPT
-A RH-Firewall-1-INPUT -p udp --dport 5353 -d 211.1.1.211 -j ACCEPT
-A RH-Firewall-1-INPUT -p udp -m udp --dport 631 -j ACCEPT
-A RH-Firewall-1-INPUT -p tcp -m tcp --dport 631 -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 8080 -j ACCEPT
-A RH-Firewall-1-INPUT -j REJECT --reject-with icmp-host-prohibited
COMMIT
network config in ubuntu shell:
$ nano /etc/network/interfaces
iface eth0 inet static
address 192.168.1.2
netmask 255.255.255.0
gateway 192.168.1.1
auto eth0
/etc/init.d/networking restart