80端口複用：利用haproxy把http流量和ssh流量分别轉發到web伺服器和ssh伺服器

    我們實驗室在學校裡面有一台伺服器，帶一個公網ip，但是隻開了一個80端口，22端口竟然不給開！！！這讓我很是不爽。之前一直待學校裡，不給開我忍忍就算了，最近搬到了個沒有校園網的偏遠地方，連不上實驗室的伺服器實在是不能忍。于是重新折騰之前安裝在伺服器上的haproxy。

    安裝教程網絡上到處到有，我按照網上的教程安裝好haproxy後，再按照知乎上的 https://www.zhihu.com/question/31528831 教程配置之後，發現隻在80端口通路網站是可以，但是用svn用戶端通路我伺服器上的svn傳回錯誤，好像是顯示option選項不支援之類的，受到 http://siukwan.sinaapp.com/?p=960 這篇文章的啟發，我覺得是在http的acl裡面配置少了option選項，于是一口氣把http所有的頭選項都回到比對項裡，像這樣子：

#GET POS(T) PUT DEL(ETE) OPT(IONS) HEA(D) CON(NECT) TRA(CE) 
	acl is_http req.payload(0,3) -m bin 474554 504f53 505554 44454c 4f5054 484541 434f4e 545241
           

    于是把svn的問題解決了。

    接下來是ssh的問題，直接在acl比對字元串SSH，然後每次在本地連接配接80端口都是傳回以下錯誤：

ssh_exchange_identification: Connection closed by remote host
           

    而直接連接配接22端口卻沒有問題。在網上搜尋這個錯誤都說是黑名單之類的錯誤，但是我覺得這裡并不是這個原因。後來抓包研究了下ssh協定，覺得并不是所有ssh資料包開頭都是字元串SSH，是以acl簡單粗暴地認為隻有以字元串SSH開頭的包才轉發到22端口是不對的，應該更加簡單粗暴地把http以外的資料包都轉發到22端口，于是我把轉發到22端口的配置語句的if條件去掉，問題得以解決。

以下是完整的配置檔案/etc/haproxy/haproxy.cfg，其中http和ssh功能是測試過的，https沒有測試，不知道能不能用。22端口是ssh伺服器，82端口是http伺服器，都是從外網的80端口進行通路。

#---------------------------------------------------------------------
# Example configuration for a possible web application.  See the
# full configuration options online.
#
#   http://haproxy.1wt.eu/download/1.4/doc/configuration.txt
#
#---------------------------------------------------------------------

#---------------------------------------------------------------------
# Global settings
#---------------------------------------------------------------------
global
    # to have these messages end up in /var/log/haproxy.log you will
    # need to:
    #
    # 1) configure syslog to accept network log events.  This is done
    #    by adding the '-r' option to the SYSLOGD_OPTIONS in
    #    /etc/sysconfig/syslog
    #
    # 2) configure local2 events to go to the /var/log/haproxy.log
    #   file. A line like the following can be added to
    #   /etc/sysconfig/syslog
    #
    #    local2.*                       /var/log/haproxy.log
    #
    log         127.0.0.1 local0
    log         127.0.0.1 local1 notice

    chroot      /var/lib/haproxy
    pidfile     /var/run/haproxy.pid
    maxconn     4000
    user        haproxy
    group       haproxy
    daemon

    # turn on stats unix socket
    stats socket /var/lib/haproxy/stats

#---------------------------------------------------------------------
# common defaults that all the 'listen' and 'backend' sections will
# use if not designated in their block
#---------------------------------------------------------------------
defaults
    mode                    http
    log                     global
    option                  httplog
    option                  dontlognull
    option http-server-close
    option forwardfor       except 127.0.0.0/8
    option                  redispatch
    retries                 3
    timeout http-request    10s
    timeout queue           1m
    timeout connect         10s
    timeout client          1m
    timeout server          1m
    timeout http-keep-alive 10s
    timeout check           10s
    maxconn                 3000

#---------------------------------------------------------------------
# main frontend which proxys to the backends
#---------------------------------------------------------------------
#frontend  main *:5000
#    acl url_static       path_beg       -i /static /images /javascript /stylesheets
#    acl url_static       path_end       -i .jpg .gif .png .css .js
#
#    use_backend static          if url_static
#    default_backend             app

#---------------------------------------------------------------------
# static backend for serving up images, stylesheets and such
#---------------------------------------------------------------------
#backend static
#    balance     roundrobin
#    server      static 127.0.0.1:4331 check

#---------------------------------------------------------------------
# round robin balancing between the various backends
#---------------------------------------------------------------------
#backend app
#    balance     roundrobin
#    server  app1 127.0.0.1:5001 check
#    server  app2 127.0.0.1:5002 check
#    server  app3 127.0.0.1:5003 check
#    server  app4 127.0.0.1:5004 check

frontend main
	mode tcp
	bind *:80
	log global
	option tcplog
	log-format %ft\ %b/%s

	tcp-request inspect-delay 3s
	acl is_https req.payload(0,3) -m bin 160301
	#GET POS(T) PUT DEL(ETE) OPT(IONS) HEA(D) CON(NECT) TRA(CE) 
	acl is_http req.payload(0,3) -m bin 474554 504f53 505554 44454c 4f5054 484541 434f4e 545241
	#SSH
	acl is_ssh req.payload(0,3) -m bin 535348
	tcp-request content accept if is_http
	tcp-request content accept if is_https
	#tcp-request content accept if is_ssh
	tcp-request content accept 
	use_backend https if is_https
	use_backend http if is_http
	#use_backend ssh if is_ssh
	use_backend ssh 

backend ssh
	mode tcp
	#server ssh01 127.0.0.1:22 maxconn 10 check inter 3s
	timeout server 1h
	server server-ssh :22

backend http
	mode tcp
	server ngx01 127.0.0.1:82 maxconn 10 check inter 3s

backend https
	mode tcp
	server ngx02 127.0.0.1:433 maxconn 10 check inter 3s