OSX 10.11 El Capitan的80端口转发

升级到OSX 10.11 El Capitan版本后，在本地需要开启80端口转发到9000端口以测试web程序可以这样做：

使用pfctl实现该需求

1. 创建anchor文件 /etc/pf.anchors/<CUSTOM NAME>:

rdr pass on lo0 inet proto tcp from any to any port 80 -> 127.0.0.1 port 9000
rdr pass on lo0 inet proto tcp from any to any port 443 -> 127.0.0.1 port 9001

1. 创建pfctl配置文件 /etc/pf-<CUSTOM NAME>.conf:

rdr-anchor "forwarding"
load anchor "forwarding" from "/etc/pf.anchors/<CUSTOM NAME>"

1. 应用规则，开启转发：

sudo pfctl -ef /etc/pf-<CUSTOM NAME>.conf

如果想取消端口转发，执行下列命令：

sudo pfctl -df /etc/pf-<CUSTOM NAME>.conf

设置为系统开启自动开启该功能

1. 创建文件 /Library/LaunchDaemons/com.apple.pfctl-<CUSTOM NAME>.plist:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
     <key>Label</key>
     <string>com.apple.pfctl-<CUSTOM NAME></string>
     <key>Program</key>
     <string>/sbin/pfctl</string>
     <key>ProgramArguments</key>
     <array>
          <string>pfctl</string>
          <string>-e</string>
          <string>-f</string>
          <string>/etc/pf-<CUSTOM NAME>.conf</string>
     </array>
     <key>RunAtLoad</key>
     <true/>
     <key>KeepAlive</key>
     <false/>
</dict>
</plist>

2. 运行下列命令使得之后开启自动运行

sudo launchctl load -w /Library/LaunchDaemons/com.apple.pfctl-<CUSTOM NAME>.plist