mac 路由和DSN相关知识

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mac 路由和DSN相关知识

Mac 下上网,尤其是在双网卡一起使用的时候, 一个网卡连内网，一个网卡连外网，经常会碰到ip不通(路由问题,比较好解决)或者dns解析不了问题. 或者是在通过VPN连公司网络会插入一些内网route,导致部分网络访问不了.

即使对Linux下的DNS解析无比熟悉了，但是在Mac下还是花了一些时间来折腾，配置不好路由和DNS是不配使用Mac的，所以记录下。

route

如果ip不通就看路由表, 根据内外网IP增加/删除相应的路由信息,常用命令如下:

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sudo route -n add 10.176/16 192.168.3.1
sudo route -n add -net 10.176.0.0/16 192.168.3.1 //添加路由, 访问10.176.0.0/16 走192.168.3.1 
sudo route -n delete -net 10.176.0.0/16 192.168.3.1
sudo route -n delete 0.0.0.0 192.168.184.1
sudo route -n add 0.0.0.0 192.168.184.1  //添加默认路由访问外网 
sudo route -n delete 0.0.0.0 192.168.3.1
sudo route -n add 10.176/16 192.168.3.1
sudo route -n delete 0.0.0.0 192.168.184.1 -ifscope en0
sudo route -n add 0.0.0.0 192.168.184.1 
sudo networksetup -setdnsservers 'Apple USB Ethernet Adapter' 202.106.196.115 202.106.0.20 114.114.114.114
sudo networksetup -setdnsservers 'USB 10/100/1000 LAN' 223.5.5.5 30.30.30.30 114.114.114.114
ip route get 8.8.8.8 //linux
route get 8.8.8.8    //macos
netstat -rn          //查看路由  
netstat -nr -f inet  //只看ipv4相关路由

如果本来IP能通,连上VPN后就通不了,那一定是VPN加入了一些更精细的路由导致原来的路由不通了,那么很简单停掉VPN就能恢复或者增加一条更精确的路有记录进去,或者删掉VPN增加的某条路由.

DNS 解析

mac下DNS解析问题搞起来比较费劲,相应的资料也不多, 经过上面的操作后如果IP能通,域名解析有问题,一般都是DNS解析出了问题

mac下 /etc/resolv.conf 不再用来解析域名, 只有nslookup能用到resolv.conf

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cat /etc/resolv.conf                                                
#
# macOS Notice
#
# This file is not consulted for DNS hostname resolution, address
# resolution, or the DNS query routing mechanism used by most
# processes on this system.
#
# To view the DNS configuration used by this system, use:
#   scutil --dns
scutil --dns //查看DNS 解析器
scutil --nwi //查看网络

解析出了问题先检查nameserver

scutil –dns 一般会展示一大堆的resolver, 每个resolver又可以有多个nameserver

A scoped DNS query can use only specified network interfaces (e.g. Ethernet or WiFi), while non-scoped can use any available interface.

More verbosely, an application that wants to resolve a name, sends a request (either scoped or non-scoped) to a resolver (usually a DNS client application), if the resolver does not have the answer cached, it sends a DNS query to a particular nameserver (and this goes through one interface, so it is always “scoped”).

In your example resolver #1 “for scoped queries” can use only en0 interface (Ethernet).

修改 nameserver

默认用第一个resolver, 如果第一个resolver没有nameserver那么域名没法解析, 可以修改dns resolver的nameserver: 

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$networksetup -listallnetworkservices  //列出网卡service, 比如 wifi ,以下是我的 macos 输出
An asterisk (*) denotes that a network service is disabled.
USB 10/100/1000 LAN
Apple USB Ethernet Adapter
Wi-Fi
Bluetooth PAN
Thunderbolt Bridge
$sudo networksetup -setdnsservers 'Wi-Fi' 202.106.196.115 202.106.0.20 114.114.114.114 //修改nameserver
$networksetup -getdnsservers Wi-Fi //查看对应的nameserver, 跟 scutil --dns 类似

如上, 只要是你的nameserver工作正常那么DNS就肯定回复了

删掉所有DNS nameserver:

One note to anyone wanting to remove the DNS, just write “empty” (without the quotes) instead of the DNS: sudo networksetup -setdnsservers <networkservice> empty

networksetup用法

查看设备和配置

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$networksetup -listallnetworkservices
An asterisk (*) denotes that a network service is disabled.
USB 10/100/1000 LAN
Apple USB Ethernet Adapter
Wi-Fi
Bluetooth PAN
Thunderbolt Bridge
Thunderbolt Bridge 2
#查看网卡配置
$networksetup -getinfo "USB 10/100/1000 LAN"                                   
DHCP Configuration
IP address: 30.25.25.195
Subnet mask: 255.255.255.128
Router: 30.25.25.254
Client ID:
IPv6 IP address: none
IPv6 Router: none
Ethernet Address: 44:67:52:02:16:d4
$networksetup -listallhardwareports
Hardware Port: USB 10/100/1000 LAN
Device: en7
Ethernet Address: 44:67:52:02:16:d4
Hardware Port: Wi-Fi
Device: en0
Ethernet Address: 88:66:5a:10:e4:2b
Hardware Port: Thunderbolt Bridge
Device: bridge0
Ethernet Address: 82:0a:d5:01:b4:00
VLAN Configurations
===================
$networksetup -getinfo "Thunderbolt Bridge"
DHCP Configuration
Client ID:
IPv6: Automatic
IPv6 IP address: none
IPv6 Router: none
//查看wifi和热点
networksetup -listpreferredwirelessnetworks en0 
networksetup -getairportnetwork "en0"

dhcp、route、domain配置

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[-setmanual networkservice ip subnet router]
[-setdhcp networkservice [clientid]]
[-setbootp networkservice]
[-setmanualwithdhcprouter networkservice ip]
[-getadditionalroutes networkservice]
[-setadditionalroutes networkservice [dest1 mask1 gate1] [dest2 mask2 gate2] ..
. [destN maskN gateN]]
#给网卡配置ip、网关
$ networksetup -getinfo "Apple USB Ethernet Adapter"                                DHCP Configuration
Client ID:
IPv6: Automatic
IPv6 IP address: none
IPv6 Router: none
Ethernet Address: (null)
$networksetup -setmanual "Apple USB Ethernet Adapter" 192.168.100.100 255.255.255.0 192.168.100.1
$networksetup -getinfo "Apple USB Ethernet Adapter"
Manual Configuration
IP address: 192.168.100.100
Subnet mask: 255.255.255.0
Router: 192.168.100.1
IPv6: Automatic
IPv6 IP address: none
IPv6 Router: none
Ethernet Address: (null)

代理配置

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//ftp
[-getftpproxy networkservice]
[-setftpproxy networkservice domain portnumber authenticated username password]
[-setftpproxystate networkservice on | off]

网页

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[-getwebproxy networkservice]
[-setwebproxy networkservice domain portnumber authenticated username password]
[-setwebproxystate networkservice on | off]
$networksetup -setwebproxy "Built-in Ethernet" proxy.company.com 80
$networksetup -setwebproxy "Built-In Ethernet" proxy.company.com 80 On authusername authpassword

Socks5 代理

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$networksetup -setsocksfirewallproxy "USB 10/100/1000 LAN" 127.0.0.1 13659
$networksetup -getsocksfirewallproxy "USB 10/100/1000 LAN"
Enabled: Yes
Server: 127.0.0.1
Port: 13659
Authenticated Proxy Enabled: 0

总结

mac同时连wifi(外网或者vpn)和有线(内网), 如果内网干扰了访问外部ip, 就检查路由表,调整顺序. 如果内网干扰了dns,可以通过scutil –dns查看dns顺序到系统配置里去掉不必要的resolver

参考资料

macOS的networksetup命令来管理网络

在Mac下使用脚本重载proxy自动配置脚本（pac）