++++++++++++
                            +  Client  +   eth0 192.168.1.1/24
                            ++++++++++++
                                 |
                                 |
                            ++++++++++++   up   eth0:192.168.1.254/24
                            +     GW   +
                            ++++++++++++   down eth1:1.1.1.254/24
                                  |
                                  |
                            ++++++++++++   VIP eth0:1.1.1.1/24
                            + Director +
                            ++++++++++++   DIP eth1:172.16.1.254/24
                                 |        
                      ___________|____________
                     |                        | 
                     |                        |
         ++++++++++++                 ++++++++++++++
        + Real Server A  +         + Real Server B  +
         ++++++++++++                 ++++++++++++++
         eth0:172.16.1.1/24             eth0:172.16.1.2/24

1、配置LVS VS/NAT模式

Client:

 [root@localhost ~]# route add default gw 192.168.1.254 dev eth0

GW:

 [root@localhost ~]# echo 1 > /proc/sys/net/ipv4/ip_forward

Real Server A & Real Server B:

 [root@localhost ~]# yum install httpd
 [root@localhost ~]# route add default gw 172.16.1.254 dev eth0

Director:

 [root@localhost ~]# echo 1 > /proc/sys/net/ipv4/ip_forward
 [root@localhost ~]# route add default gw 1.1.1.254 dev eth0
 [root@localhost ~]# yum install ipvsadm
 [root@localhost ~]# ipvsadm -A -t 1.1.1.1:80 -s rr
 [root@localhost ~]# ipvsadm -a -t 1.1.1.1:80 -r 172.16.1.1:80 -m
 [root@localhost ~]# ipvsadm -a -t 1.1.1.1:80 -r 172.16.1.2:80 -m
 [root@localhost ~]# ipvsadm -Ln
 [root@localhost ~]# ipvsadm -Ln --stats

2、数据包走向

 1.Client---------->GW

 sip:CIP           dip:VIP
 smac:Client_mac     dmac:GW_up_mac

 2.GW-------------->Director
 sip:CIP         dip:VIP
 smac:GW_down_mac     dmac:VIP_mac

 3.Director-------->Real Server (DNAT)
 sip:CIP         dip:RIP
 smac:DIP_mac     dmac:RealServer_mac

 4.Real Server----->Director
 sip:RIP                    dip:CIP
 smac:RealServer_mac        dmac:DIP_mac

 5.Director-------->GW
 sip:VIP         dip:CIP
 smac:VIP_mac     dmac:GW_down_mac

 6.GW-------------->Client
 sip:VIP         dip:CIP
 smac:GW_up_mac     dmac:Client_mac