一:背景

公司最近Exchange邮件系统来构建高可用邮件系统架构。前端负载均衡就是使用了微软的NLB来实现cas的负载均衡。但是方案实施工程中也发现了一些问题，使用NLB在网络中产生大量广播报，出现丢包严重问题。后改用haproxy替代NLB实现cas的负载均衡，但也这就导致了一个问题，最明显的就是用户通过Haproxy来访问邮件系统后 真正达到邮件系统的地址都是Haproxy的地址，在垃圾邮件过滤的时候就无法实现基于IP的过滤，并且也无法记录IP地址信息。为 了解决这个问题我google了很多方案，可以使用硬负载，硬负载可以实现全透明代理让后端邮件服务器获取到用户的真实IP，还有一种解决方案就是 Haproxy的全透明代理。接下来将会介绍下Haproxy的全透明代理的部署。

二:实验拓扑

三:方案部署

配置Haproxy

#!/bin/bash
wget http://haproxy.1wt.eu/download/1.4/src/haproxy-1.4.25.tar.gz
tar zxvf haproxy-1.4.25.tar.gz
cd haproxy-1.4.25
yum install gcc gcc-c++ autoconf automake -y
make TARGET=linux2628 arch=x86_64 USE_LINUX_TPROXY=1 #重点USE_LINUX_TPROXY=1用于编译支持TPTOXY
make install
mkdir /etc/haproxy
cp examples/haproxy.cfg /etc/haproxy
cp examples/haproxy.init /etc/init.d/haproxy
chmod +x /etc/init.d/haproxy
cp haproxy /usr/sbin/

修改配置文件/etc/haproxy/haproxy.cfg
global
log 127.0.0.1  local0
maxconn 409600
chroot /usr/local/share
#  uid 501
#  gid 501
daemon
nbproc 1
pidfile /usr/local/haproxy/logs/haproxy.pid
#  debug
defaults
log global
maxconn 100000
contimeout 500000
clitimeout 3600000
srvtimeout 3600000
option redispatch
retries 6
frontend mail.domain.com
mode http
bind 0.0.0.0:80
log global
option tcplog
redirect location https://mail.domain.com/owa
frontend owa_443
mode tcp
bind 0.0.0.0:443
default_backend pool_443
log global
option tcplog
backend  pool_443
balance source
option redispatch
option abortonclose
option persist
stick on src
stick-table type ip size 10240k expire 240m
source 0.0.0.0  usesrc clientip #重点,TPROXY需要加上这行。
server cas01 10.130.170.130:443 check inter 5000 weight 1 rise 2 fall 3
server cas02 10.130.170.131:443 check inter 5000 weight 1 rise 2 fall 3
frontend smtp_25
mode tcp
bind 0.0.0.0:25
default_backend pool_smtp
log global
option tcplog
backend pool_smtp
balance source
option redispatch
option abortonclose
option persist
stick on src
stick-table type ip size 10240k expire 240m
source 0.0.0.0  usesrc clientip #重点,TPROXY需要加上这行。
server cas01 10.130.170.130:25 check inter 5000 weight 1 rise 2 fall 3
server cas02 10.130.170.131:25 check inter 5000 weight 1 rise 2 fall 3
frontend pop_995
mode tcp
bind 0.0.0.0:995
default_backend pool_pop
log global
option tcplog
backend pool_pop
balance source
option redispatch
option abortonclose
option persist
stick on src
stick-table type ip size 10240k expire 240m
server cas01 10.130.170.130:995 check inter 5000 weight 1 rise 2 fall 3
server cas02 10.130.170.131:995 check inter 5000 weight 1 rise 2 fall 3
frontend pop_993
mode tcp
bind 0.0.0.0:993
default_backend pool_993
log global
option tcplog
backend pool_993
balance source
#  option forwardfor
#  option originalto
option redispatch
option abortonclose
option persist
stick on src
stick-table type ip size 10240k expire 240m
server cas01 10.130.170.130:993 check inter 5000 weight 1 rise 2 fall 3
server cas02 10.130.170.131:993 check inter 5000 weight 1 rise 2 fall 3
frontend pop_135
mode tcp
bind 0.0.0.0:135
default_backend pool_135
log global
option tcplog
backend pool_135
balance source
option redispatch
option abortonclose
option persist
stick on src
stick-table type ip size 10240k expire 240m
server cas01 10.130.170.130:135 check inter 5000 weight 1 rise 2 fall 3
server cas02 10.130.170.131:135 check inter 5000 weight 1 rise 2 fall 3
frontend pop_593
mode tcp
bind 0.0.0.0:593
default_backend pool_593
log global
option tcplog
backend pool_593
balance source
option redispatch
option abortonclose
option persist
stick on src
stick-table type ip size 10240k expire 240m
server cas01 10.130.170.130:593 check inter 5000 weight 1 rise 2 fall 3
server cas02 10.130.170.131:593 check inter 5000 weight 1 rise 2 fall 3
frontend pop_60001
mode tcp
bind 0.0.0.0:60001
default_backend pool_60001
log global
option tcplog
backend pool_60001
balance source
option redispatch
option abortonclose
option persist
stick on src
stick-table type ip size 10240k expire 240m
server cas02 10.130.170.130:60001 check inter 5000 weight 1 rise 2 fall 3
server cas02 10.130.170.131:60001 check inter 5000 weight 1 rise 2 fall 3
frontend pop_55000
mode tcp
bind 0.0.0.0:55000
default_backend pool_55000
log global
option tcplog
backend pool_55000
balance source
option redispatch
option abortonclose
option persist
stick on src
stick-table type ip size 10240k expire 240m
server cas02 10.130.170.130:55000 check inter 5000 weight 1 rise 2 fall 3
server cas02 10.130.170.131:55000 check inter 5000 weight 1 rise 2 fall 3
frontend vs_stats :8081
mode http
log global
option httplog
default_backend stats_backend
backend stats_backend
mode http
stats enable
stats uri /stats
stats auth admin:admin

3.由于ExchangeRPC的端口是动态端口，haproxy必须使用固定端口，我这里改成了60001和55000，修改注册表即可，这里不做介绍。

4.配置TProxy代码如下vi iptables.sh

#!/bin/bash
/sbin/iptables -F
/sbin/iptables -t mangle -N DIVERT
/sbin/iptables -t mangle -A PREROUTING -p tcp -m socket -j DIVERT
/sbin/iptables -t mangle -A DIVERT -j MARK --set-mark 1
/sbin/iptables -t mangle -A DIVERT -j ACCEPT
/sbin/ip rule add fwmark 1 lookup 100
/sbin/ip route add local 0.0.0.0/0 dev lo table 100

上面的代码目的是为了让所有进入网卡的mangle表的包都打上标记，然后新增一条路由规则将这些打了标记的数据包发送至本地回环接口进行处理。

chmod +x iptables.sh
./iptables.sh

修改配置 /etc/sysctl.conf
net.ipv4.ip_forward = 1
net.ipv4.conf.default.rp_filter = 2
net.ipv4.conf.all.rp_filter = 2
net.ipv4.conf.eth0.rp_filter = 0
net.ipv4.conf.all.send_redirects = 1
net.ipv4.conf.default.send_redirects = 1

7.到此为此基于TProxy的Haproxy全透明代理完成了。为真实实现高可用，haproxy也是单点故障，keepalived也不在这里介绍。

然后将两台cas server的网关改为haproxy的ip。现在可以查看到垃圾邮件的ip。