ROCK IPv4 forwarding?

Is IPv4 forwarding enabled if the ROCK m/c has more than one interface ? The Ethernet interface is dhcp enabled and Ethernet2 has static IP as follows

IP address:

IP address:

I have the Sotm sms200 renderer directly connected to Ethernet2 and has a static IP assigned as follows:
IP address:

On my Mac, which is on the network 10.0.1.x, I added a static route for the subnet pointing to using route -n add

I can ping and access the ROCK web interface on Ethernet2, i.e but I cannot ping or access sms200 This would have worked if ipv4 forwarding (/proc/sys/net/ipv4/ip_forward) is enabled on the ROCK ?


Packets will enter through your Ethernet interface but return through Ethernet2 so your set-up will cause asymmetric routing and won’t work.

Ping (icmp) has no problems with asymmetric but tcp does.


it is enabled:

# uname -a
Linux ROCK 4.9.13 #13 SMP Thu Aug 17 11:19:22 EDT 2017 x86_64 GNU/Linux
# cat /proc/sys/net/ipv4/ip_forward

Thanks! Any idea why it isn’t working ? it could possibly be an issue with the sms200 end ?

can you play audio out of the sotm? is it up and good?

Yes, I can. Rock can recognize it and it can play through it. I also connected them directly to my Mac ethernet interface (which also has a static ip address and was able to load Sotm web gui.

@danny any pointers as to what might be going wrong ?

Let me ping @brian… im stumped without playing around. With that static route, all should be ok since ROCK will have an ARP cache entry for your Mac.

any update ?

I’m in the same boat as Danny–would have to replicate your setup and fiddle to learn anything more.

This is how I would fiddle:

  • Replace sms-200 with a linux device where you can get root access.
  • Make the same connectivity tests, but while tcpdumping on the linux device to see what packets are getting in and where outgoing packets are going
  • Also do the same in reverse direction

That might give some insight into what direction is broken. Right now you have 2 black boxes–ROCK and the sms-200. You don’t yet know what is making it where. This will help narrow down where the issue is.

If I am able to get a shell into the ROCK, that is all I would need to debug it. Is there a secret way ?

we don’t have a public shell, but i’ll PM you some ideas