�b�}�l�o�ӳ��`���e�A�z�ȥ��nŪ�L�y²���������z���@���`�A�_�h�o�g�峹�̭��ܦh����ƱN�|�L�k�z�ѳ�I�n�F�A���� NAT �O����H�O Network Address Translation ���Y�g�A�o���N�ܦ���A�]���L�i�H���z�� Linux ���Ѧܤֳ�²�檺 IP ���ɾ����\��I���@�� Linux �D���i�H���Ѿ�Ӱϰ����(LAN)�����q���Ӥ��ɺ����W�e�A�]�N�O�ϰ줺�����q���q�q���i�H�z�L NAT �D���ӹF��h�H�W�����ت��o�I�o�g�峹���D�n�O²���������������N�O�F�I |
1. �ϥ� ntsysv
�]�w�}���ɱҰʪ��A�ȶ��ءG
[root@test root]# ntsysv �u�n��ܩ��U�X�ӪA�ȧY�i�G atd, cron, iptables, keytables, network, random, syslog, xinetd 2. ���s�}�����]�w�ͮġG
3. �[��ثe��
port �}�Ҧh�֭ӡH
|
[root@test
root]# vi /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0 BOOTPROTO=static BROADCAST=192.168.1.255 IPADDR=192.168.1.2 NETMASK=255.255.255.0 NETWORK=192.168.1.0 ONBOOT=yes <==���n���a��b�o�̡I�г]�w�� yes ��I # �p�G�z����o���Ӧp��]�w���ܡA�N�ӤW�������N�n�F�I |
[root@test
root]# vi /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0 BOOTPROTO=dhcp <==�o�̳̭��n�I BROADCAST=192.168.100.255 IPADDR=192.168.100.1 NETMASK=255.255.255.0 NETWORK=192.168.100.0 ONBOOT=yes # �p�G�z����o���Ӧp��]�w���ܡA�N�ӤW�������N�n�F�I |
[root@test
root]# vi /etc/sysconfig/network-scripts/ifcfg-eth0:0
DEVICE=eth0:0 BOOTPROTO=static BROADCAST=192.168.1.255 IPADDR=192.168.1.2 NETMASK=255.255.255.0 NETWORK=192.168.1.0 ONBOOT=yes # �p�G�z����o���Ӧp��]�w���ܡA�N�ӤW�������N�n�F�I |
[root@test
root]# ifdown eth0
[root@test root]# ifup eth0 [root@test root]# route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface swks81-1.adsl.s * 255.255.255.255 UH 0 0 0 ppp0 192.168.1.0 * 255.255.255.0 U 0 0 0 eth0 127.0.0.0 * 255.0.0.0 U 0 0 0 lo default swks81-1.adsl.s 0.0.0.0 UG 0 0 0 ppp0 # �K�K�I�o�˴N�O���\�աI�`�N�A�W���o�Ӹ��ѬO�H adsl �������Ҫ��I |
1. �N�p�� IP
�[�J�� /etc/hosts �̭��h�a�I
[root@test root]# vi /etc/hosts 127.0.0.1 localhost 192.168.1.1 linux001 192.168.1.2 linux002 .......(��)...... 192.168.1.100 linux100 .......(��)...... 192.168.1.254 linux254 2. �N DNS ��
IP �g�� /etc/resolv.conf �̭��h�A�o�̥H���عq�H�� Seednet ����
3. �]�w�D���W�ٸ�
gateway �P�_�G
|
echo "1" >
/proc/sys/net/ipv4/ip_forward
modprobe ip_tables modprobe ip_nat_ftp modprobe ip_nat_irc modprobe ip_conntrack modprobe ip_conntrack_ftp modprobe ip_conntrack_irc /sbin/iptables -F /sbin/iptables -X /sbin/iptables -Z /sbin/iptables -F -t nat /sbin/iptables -X -t nat /sbin/iptables -Z -t nat /sbin/iptables -P INPUT DROP /sbin/iptables -P OUTPUT ACCEPT /sbin/iptables -P FORWARD ACCEPT /sbin/iptables -t nat -P PREROUTING ACCEPT /sbin/iptables -t nat -P POSTROUTING ACCEPT /sbin/iptables -t nat -P OUTPUT ACCEPT /sbin/iptables -t nat -A POSTROUTING -o ppp0 -s 192.168.1.0/24 -j MASQUERADE |
[root@test
root]# cd /usr/local/virus/iptables
[root@test iptables]# vi iptables.rule #!/bin/bash #...(��)... # �]�w��~���������� EXTIF="ppp0" # �]�w�鷺�����������P�����p�����쪺�]�w INIF="eth0" INNET="192.168.1.0/24" # This is for NAT's network #....(��).... if [ "$INIF" != "" ]; then /sbin/iptables -A INPUT -i $INIF -j ACCEPT echo "1" > /proc/sys/net/ipv4/ip_forward /sbin/iptables -t nat -A POSTROUTING -s $INNET -o $EXTIF -j MASQUERADE fi #...(��)... |
[root@test
root]# vi /etc/sysconfig/network-scripts/ifcfg-eth1
DEVICE=eth1 BOOTPROTO=static BROADCAST=192.168.0.255 IPADDR=192.168.0.2 NETMASK=255.255.255.0 NETWORK=192.168.0.0 ONBOOT=no <==�o�̫ܭ��n�I��~�ΨӼ������d���n�b�}�����ɭԱҰʰաI |
�b Client �ݪ��]�w�u�O²�檺�i�H�F�I�ѩ�ڭ̤W��������]�w���O 192.168.1.0/24 �o�� C Class ���p������A�ҥH�z�u�n�O�o�X��Ʊ��G
�j�P�W�N�O�o�˰աI�ܩ� Client �ݳq�`�O Windows �A�������]�w�i�H�e���ѦҤ@�U�ϰ�����]�w�@�����I�ܩ� Linux �ݫh�ݭn�d�ݤ@�U �s�W Internet �̭����T�w IP ���]�w�աI
- network �]�w�ݭn���G 192.168.1.0
- broadcast �]�w�ݭn���G 192.168.1.255
- netmask �]�w�ݭn�� 255.255.255.0
- IP �]�w�ݭn�� 192.168.1.1 ~ 192.168.1.254 ���@�A�B�y���୫�ơz
- Gateway �Ϊ̻��O �q�T�h �ݭn�]�w���z�� Linux ���鷺 IP �A�H�ڪ��Ҥl�ӻ��A�N�O 192.168.1.2 �I
- DNS ���]�w�G�o�ӳ̮e���X���F�A�z�� DNS �]�w�ݭn�O�z�� ISP ���z�� DNS IP�A�p�G�z�����D���ܡA�i�H��J 168.95.1.1 �o�@�Ӥ��عq�H�� DNS �Ϊ̬O 139.175.10.20 �o�@�� SeedNet �� DNS �Y�i�I�d�U���n�]�w�� 192.168.1.2 ��I�|�s���X�h�I
�Ъ`�N�A�b�o�ӨҤl�����A�ڭ̨èS���ϥΨ�ʥ]���R���ʧ@�A�����u�� IP ���˦Ӥw�A�ҥH�G
- ��� Client �ݨӻ��A�ѩ�w�g�g�L�F IP ���˪��\��A�ҥH�W�A�z�q�L NAT �D���s�X�h���ʥ]�� IP ���|�O�y NAT �D����~�����@ IP �z�A�]����� Client �ݦӨ��A�ѩ���� Cracker �X�G���O�ھ� IP �Ӷi��}�a�A�Ӧ]���z�s�X�h���ʥ] IP �O NAT �D�������@ IP �A�۵M�z�� Client �ݴN����w���h�F�I�W�A Client �ݦb NAT �����A�S���w��������n���]�٦n�A���O�y���r�n��@�w�n�w���I�z�]���z�����|�����q�l�l��r�������A�ҥH�٬O�i��|���r�աI�I
- ��� Server �ݨӻ��A�ڭ̶ȶȳ]�w�@��²�檺������W�h�A�ӥB�b�쥻�� iptables.rule �����ٹw�]�}�ҤF�\�h����f�A�ҥH���o�˪��@�ӥD���ä��O�Q�����w�����A�]���A�z�̦n�٬O�ۦ�N iptables.rule �����̫᭱���X�Ӷ}��f���L���ѱ��~�n�o�I(�p�G�z�� NAT �D���ȷQ�n�t�d�W�e���ɪ��\��ܡI)