OPNsense Forum

Archive => 17.7 Legacy Series => Topic started by: mario on November 04, 2017, 07:48:25 am

Title: Why won't unmanaged switch work behind Opnsense firewall box?
Post by: mario on November 04, 2017, 07:48:25 am

Hi - simple newbie question I think, but very frustrating...

I've recently set up a firewall box using Opnsense, and it works great: I have internet access when I connect my computer directly to the LAN port.

However, when I connect my unmanaged switch as an intermediary between the firewall and my computer, I have no Internet.  What do I need to do to make this work?

The configuration is: Modem -> Opnsense firewall machine -> unmanaged hub -> computer
I've tried the obvious sequential power-up of Modem, then Opnsense, then switch, then computer, but still nothing.  All the cables work, and the ethernet plug lights all indicate successful connections.

I'm sure that there is some simple, obvious solution, so what could it be?...

Title: Re: Why won't unmanaged switch work behind Opnsense firewall box?
Post by: fabian on November 04, 2017, 08:54:34 am

maybe your nic is unable to cross the wires and you are using the wrong cables.

switch to host: straight through
switch to firewall: straight through
host to firewall: cross over

Title: Re: Why won't unmanaged switch work behind Opnsense firewall box?
Post by: xinnan on November 04, 2017, 11:33:36 am

Is this a known to be working switch?

What is the brand and model number?

And like fabian asked, are you buying or making wire?  If you made it, what did you make?

If you bought it, what did you buy?

Right now, looks like either a switch or wire issue. 

Title: Re: Why won't unmanaged switch work behind Opnsense firewall box?
Post by: Oxygen61 on November 04, 2017, 03:27:25 pm

Hi mario,

indeed that sounds really odd.
You to make sure that crossover/straight through cable selection is NOT the error you will need to check the following:
Please look if your PC NIC is able to use "Auto MDI-X" and also check if your unmanaged Switch is able to use Auto MDI-X by default aswell.
Source: https://en.wikipedia.org/wiki/Medium-dependent_interface

If both sides are able to auto-communicate wether the communication needs to be crossed over or not you can then say that this is not the problem you are facing right now.
Good unmanaged switches are cheap, just check if you can lend one for testing purposes or something. :)

Title: Re: Why won't unmanaged switch work behind Opnsense firewall box?
Post by: xinnan on November 04, 2017, 03:48:50 pm

So far, we know that some kind of NIC is attached to some model of switch by some kind of wire and it doesn't work.  Really, no information has been shared.

Is this top secret hardware, so that the brands and models can't be shared?  If so, I think its going to be a long thread.