Friday, November 6, 2020

How to add and delete Static Routes on macOS (persistently)


● Problem


I have several networks at home, including 192.168.1.0/24 and 192.168.2.0/24. A problem occurred when I connected to a VPN site because it gives a route with 192.168.2.0/23. So my traffic on 192.168.2.0/24 routed through the VPN tunnel instead of my internal home network.

Therefore, I need to add a static route on my MacBook Pro.

● Solution


Here is how to add or delete a static route on macOS.

As you see below, I received the 192.168.2.0/23 route from the VPN, and it routes through the tunnel interface, utun3. First, disconnect the VPN and add a static route as described below.

To view the routing table:

You can use the following command "netstat -rn" and use 'grep' to filter with a specific network on the Terminal.

macOS:/Users/analysisman% netstat -rn | grep 192.168.2.
192.168.2/23 1.1.1.1 UGSc utun3



▶ Method 1. Add a static route temporarily


To add a static route:


macOS:/Users/analysisman% sudo route -n add -net 192.168.2.0/24 192.168.1.1
add net 192.168.2.0: gateway 192.168.1.1



To verify the route you added:


macOS:/Users/analysisman% netstat -rn | grep 192.168.2.
192.168.2 192.168.1.1 UGSc en10
192.168.2/23 1.1.1.1 UGSc utun3


Now, 192.168.2.0/24 routes through my Ethernet interface, en10.


To delete a static route:


macOS:/Users/analysisman% sudo route -n delete 192.168.2.0/24
Password:
delete net 192.168.2.0



▶ Method 2. Add a static route persistently


The above route will be gone if you reboot your Mac. You need to add a static route permanently if you want to keep this route persistently.


To verify the route your interface:


macOS:/Users/analysisman% ifconfig -a
…snipped…

en10: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
options=6407<RXCSUM,TXCSUM,VLAN_MTU,CHANNEL_IO,PARTIAL_CSUM,ZEROINVERT_CSUM>
ether 00:24:9b:33:44:55
inet6 fe80::3f:e0d:4455:1ebe%en10 prefixlen 64 secured scopeid 0xb
inet 192.168.1.103 netmask 0xffffff00 broadcast 192.168.1.255
nd6 options=201<PERFORMNUD,DAD>
media: autoselect (1000baseT <full-duplex>)



To list devices (network adapters):


macOS:/Users/analysisman% networksetup -listallnetworkservices

An asterisk (*) denotes that a network service is disabled.
FT232R USB UART
USB 10/100/1000 LAN 2
USB 10/100/1000 LAN
USB 10/100/1000 LAN 3
USB 10/100/1000 LAN 4
USB 10/100/1000 LAN 5
Belkin USB-C LAN
Wi-Fi
iPhone USB 2
Bluetooth PAN
Thunderbolt Bridge
GlobalProtectDo
GlobalProtectDo 2


Or

To list devices with the interface number:


I prefer this command because it also shows the ethernet number (e.g. en10).

macOS:/Users/analysisman% networksetup -listnetworkserviceorder

An asterisk (*) denotes that a network service is disabled.
(1) FT232R USB UART
(Hardware Port: FT232R USB UART, Device: usbserial-AI06J8P5)

(2) USB 10/100/1000 LAN 2
(Hardware Port: USB 10/100/1000 LAN, Device: en8)

(3) USB 10/100/1000 LAN
(Hardware Port: USB 10/100/1000 LAN, Device: en10)



To add a static route permanently:


Usage:
networksetup -setadditionalroutes <networkservice> [ <dest> <mask> <gateway> ]*

macOS:/Users/analysisman% sudo networksetup -setadditionalroutes "USB 10/100/1000 LAN" 192.168.2.0 255.255.255.0 192.168.1.1


To verify the route you added:


macOS:/Users/analysisman% netstat -rn | grep 192.168.2.
192.168.2 192.168.1.1 UGSc en10


To delete this permanent route:


Use sudo networksetup -setadditionalroutes interface-name without the address, netmask, and gateway.

macOS:/Users/analysisman% sudo networksetup -setadditionalroutes "USB 10/100/1000 LAN"


To see all commands:


networksetup -help
Or
networksetup -printcommands


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