0

I have an IoT device that runs a small HTTP server, which I access through Ethernet.

My Ethernet is routed through 192.168.1.3 and configured manually.

I can access the device with no issues when my Wi-Fi is turned off:

curl 192.168.1.2/?connect
response OK

This is the content of my routing table when my Wi-Fi is off and Ethernet is connected (en4):

netstat -nr
Routing tables

Internet:
Destination        Gateway            Flags        Netif Expire
127                127.0.0.1          UCS            lo0
127.0.0.1          127.0.0.1          UH             lo0
169.254            link#7             UCS            en4      !
192.168.1          link#7             UCS            en4      !
192.168.1.1        link#7             UHLWI          en4      !
192.168.1.2        2:4c:db:14:60:9a   UHLWIi         en4   1174
192.168.1.3/32     link#7             UCS            en4      !
192.168.1.3        5c:85:7e:3e:99:f4  UHLWI          lo0
192.168.1.99       link#7             UHRLWI         en4      !
192.168.1.219      link#7             UHRLWI         en4      !
192.168.1.226      link#7             UHRLWI         en4      !
192.168.1.230      link#7             UHRLWI         en4      !
224.0.0/4          link#7             UmCS           en4      !
224.0.0.251        1:0:5e:0:0:fb      UHmLWI         en4
255.255.255.255/32 link#7             UCS            en4      !

Everything works fine as long as I only use my Ethernet. However, as soon as I activate my Wi-Fi, I lose connection and cannot access my device anymore. Curl hangs and timeouts.

This is the content of my routing table after activating my Wi-Fi (en0):

netstat -nr
Routing tables

Internet:
Destination        Gateway            Flags        Netif Expire
default            192.168.1.1        UGScg          en0
127                127.0.0.1          UCS            lo0
127.0.0.1          127.0.0.1          UH             lo0
169.254            link#4             UCS            en0      !
169.254            link#7             UCSI           en4      !
192.168.1          link#4             UCS            en0      !
192.168.1          link#7             UCSI           en4      !
192.168.1.1/32     link#4             UCS            en0      !
192.168.1.1        ac:d5:64:fe:e2:e7  UHLWIir        en0   1185
192.168.1.2        link#4             UHLWIi         en0      !
192.168.1.3/32     link#7             UCS            en4      !
192.168.1.3        5c:85:7e:3e:99:f4  UHLWIi         lo0
192.168.1.99       60:ab:d2:fb:73:2f  UHLWIi         en0   1154
192.168.1.184/32   link#4             UCS            en0      !
192.168.1.185      84:f7:3:a9:83:e0   UHLWI          en0   1183
192.168.1.213      34:b4:72:f:ab:94   UHLWI          en0   1176
192.168.1.219      d4:f5:47:29:3b:3c  UHLWIi         en0   1154
192.168.1.226      1c:53:f9:4:32:ff   UHLWIi         en0   1150
192.168.1.230      a4:77:33:9a:1b:30  UHLWIi         en0   1185
192.168.1.255      ff:ff:ff:ff:ff:ff  UHLWbI         en0      !
192.168.1.255      ff:ff:ff:ff:ff:ff  UHLWbI         en4      !
224.0.0/4          link#4             UmCS           en0      !
224.0.0/4          link#7             UmCSI          en4      !
224.0.0.251        1:0:5e:0:0:fb      UHmLWI         en0
239.255.255.250    1:0:5e:7f:ff:fa    UHmLWI         en0
239.255.255.250    1:0:5e:7f:ff:fa    UHmLWI         en4
255.255.255.255/32 link#4             UCS            en0      !
255.255.255.255/32 link#7             UCSI           en4      !

I have tried to set up a static route to map my IoT device to the Ethernet Gateway (en4), which adds the following line to the routing table:

192.168.1.2        192.168.1.3        UGHS           en4

However, I still receive no response from the device.

I suspect that my HTTP calls are being routed through my Wi-Fi instead of reaching my Ethernet connection.

How can I configure my routing table to ensure that traffic is sent to my device via Ethernet?

Miki
  • 121
  • 1
  • 5

1 Answers1

2

It sounds like your IoT device and your Mac's Ethernet interface are on a standalone Ethernet LAN, which is not actually connected to your larger home LAN that your Wi-Fi is attached to.

Unfortunately you're using the same IP subnet for both networks: the 192.168.1.0/24 subnet (that includes all addresses in the range 192.168.1.0 - 192.168.1.255). So you've told your Mac that its Wi-Fi and its Ethernet port are connected to the same network (subnet), but in reality they are not.

If you can, connect your IoT device to your home LAN. If that is not convenient, then change the IP address of your IoT device to put it on a different subnet so that it does not conflict with your home LAN. For example, change the third octet from "1" to "2". So put your IoT device on 192.168.2.2/24, and put your Mac's Ethernet interface on 192.168.2.3/24. (BTW, "/24" is a shorthand way of saying your subnet mask is 255.255.255.0)

Spiff
  • 110,156