SOLVED Second nic connected causes misbehave on two separate networks

Revolution

Dabbler
Joined
Sep 8, 2015
Messages
39
Hey everyone,

I have a rather strange behavior of my c2550d4i motherboard.

First of all, the board has 3 nics,1 for ipmi, one igb0 and one igb1. For the past I just had the igb0 connected on a 192.168.5.0/24 subnet and all is working flawless. Yesterday I thought, since I'm using vlans on my switch and other networks have to go through the firewall to access the Nas, I could just plug the igb1 into one of the other networks to speed up the connection. Well it wasn't that easy.

After I connected the second nic to my 192.168.7.0/24 subnet, the nic wouldn't ask for a ip. So I just went to the cmd and ran dhclient igb1 and got an ip. This is where it gets strange. After doing that, the webgui access to the 5.0/24 subnet was super slow and sporadic, most clicks around the gui would be blank and just very abrupt.So I restarted the machine to see if it fixes it. After doing so nothing changed really. I thought to myself, well then I'll disconnect the link connected to 7.0/24. After doing that, the 5.0/24 nic which worked all the time just wasn't ping able nor did the webgui respond in any way. After a period it would just work again and the sporadic and abrupt webgui was buttersmooth again.

Now my question. What could cause such behavior? These are two separate broadcast domains so and also two separate Mac addresses. My machine from which I connect to the gui is also on the 7.0/24 subnet.

Ultimately I would like to bind only the smb service to the igb1 (7.0/24) nic and the gui and ssh to the management nic. The goal is to get wirespeed smb to the 7.0/24 network without exposing anything else on that subnet.

Maybe someone has an idea how I could debug the behavior

With kind regards
 

jgreco

Resident Grinch
Joined
May 29, 2011
Messages
18,681
This implies you're using DHCP. Your default gateway is being janked around. I am told by people who think they know much better than me that this "should work" and "works on pfSense" and other nonsense.

The real fix is to avoid using DHCP with an infrastructure server device such as a NAS and wire it down to a specific IP and default gateway. When you do this correctly, it will work swimmingly well with multiple network connections, you just bring up the second network connection with the desired IP address. It's my opinion that you should *NOT* run "dhclient" anything, ever, unless you're just setting up the NAS for the first time and trying to bootstrap it onto the network.
 

Revolution

Dabbler
Joined
Sep 8, 2015
Messages
39
Thank you very much for the quick answer. It mostly fixed the issues. The only problem remaining is that the gui is still slow and unresponsive as soon as I assign the second nic an ip. I just got the "connecting to freenas... " screen and got sent back to the login screen and without typing anything in directly to the desired link. Steps to reproduce : start at the dashboard, wait 15 seconds, click on storage then pool. The dashboard turns blank and as stated above I get the connection issue screen. There is also no problem with ssh only with the gui it seems.

Edit: if I wait long enough, I get the screen with the connection issue as well. Is there any way I can debug this further?

With kind regards
 

no_connection

Patron
Joined
Dec 15, 2013
Messages
480
IMO the screen with the connection issue is total BS and is a (or the) problem. The connection can work perfectly fine and the "no connection to freenas" pops up and won't let you log in. Even tho you just loaded the page from the NAS for the first time. It does not happen often but oh boy that thing is annoying and more harm than good. Just let the page time out like normal things.

There are reasons why you might want to use DHCP on multiple interface and I get that, and it *can* work. There are just more reasons not to. Which is why it won't let you do it. Split brain do cause headaches, both in real life and in networking.

Another option is 1:1 NAT if you want it in same subnet or just regular NAT if you are fine with typing the real IP. There is no reason why you should not be able to route wire speed. Or just skip NAT if you have all the needed routes.
 

Revolution

Dabbler
Joined
Sep 8, 2015
Messages
39
Thank you for your reply.

I ended up activating the gui and ssh on both links and it works normal when using on the same subnet so I just went with that. I actually use static ips for both nics now. Also I can't route wirespeed because my layer 3 firewall pfsense is an older apu from pc engines with Realtek nics so they are the bottleneck. I'm already looking for a replacement but that is another topic. Anyway thank you for your input, I appreciate it.
 
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