from flask import Flask

app = Flask(__name__)

@app.route('/')
def hello_world():
    return 'Hello World!'

if __name__ == '__main__':
    app.run(port=5000)

# 开启 IPv4 的转发
$ sudo sysctl -w net.inet.ip.forwarding=1

# 查看当前端口转发功能状态
sudo sysctl -a | grep forward
net.inet.ip.forwarding: 1
net.inet6.ip6.forwarding: 0

sudo vim /etc/pf.anchors/http

rdr pass on lo0 inet proto tcp from any to any port 8080 -> 127.0.0.1 port 5000
rdr pass on en0 inet proto tcp from any to any port 8080 -> 127.0.0.1 port 5000

$ ifconfig -a
# lo0 是本机ipv4地址 eg: 127.0.0.1
# en0 是局域网ipv4地址 eg: 192.168.0.100

$ sudo pfctl -vnf /etc/pf.anchors/http

sudo vim /etc/pf.conf

# 在 rdr-anchor "com.apple/*" 下添加
rdr-anchor "http-forwarding"

# 在 load anchor "com.apple" from "/etc/pf.anchors/com.apple" 下添加
load anchor "http-forwarding" from "/etc/pf.anchors/http"

sudo pfctl -ef /etc/pf.conf

# 启用pf服务
$ sudo pfctl -e

# 强制重启PF服务
$ sudo pfctl -E

# 关闭PF
$ sudo pfctl -d