Thanks Adam. 

But I shouldn't have to reduce the MTU across the entire network, since I'm 
really only using the VLAN tagging on ports which exist within the pfsense box, 
correct? For example, in my diagram, packets which reach LAN switch A and B 
won't be tagged...at least, I don't think they will be...what I think *should* 
happen is that the tagging will get added and stripped at the nics which exist 
in the pfsense boxes. 

Additionally, I have two quad port cards, one newer (which I'm not 100% certain 
supports the additional bytes added by vlans but am hoping to find out) and one 
older. You seem to imply I only need one port on the newer card to support the 
inter-pfsense link, but as far as I can tell I'd need it on both pfsense boxes 
(one port per box) to do what I'm trying to do, since the different networks 
exist at each end of the trunk, correct? 


----- Original Message -----

From: "Adam Thompson" <[email protected]> 
To: "pfSense support and discussion" <[email protected]> 
Sent: Monday, December 30, 2013 11:48:12 AM 
Subject: Re: [pfSense] pfsense <-> pfsense vlans and trunking without the aid 
of switches 

On 13-12-30 10:32 AM, Adam Thompson wrote: 


Any Ethernet card can support VLANs. However, the 802.1q standard specifies 
that VLAN tags take an extra 4(?) bytes, so more modern cards can actually 
handle Ethernet frames that are 4 bytes longer than they should be. If your 
card can't handle the extra length, the maximum packet size will drop by 4 
bytes, so you'll have a lower MTU on that link, and you should then take care 
to 



Whoops. 

...take care to reduce the MTU throughout your entire network, or at least on 
the pfSense-to-pfSense link. If this happens, it may cause you some issues. The 
simple solution would be to use the old card for an UN-tagged connection, and 
use one of the quad ports on the newer card as the inter-pfSense link. All the 
ethernet ports on each system are interchangeable - there's nothing magic about 
one being on-board, or anything like that. In fact, you should probably use the 
"best" NIC in each system (for varying definitions of "best") as the trunk 
port, since it'll have to work the hardest of anything. 

FWIW, almost any open-source UNIX-based system can act as a bridge, and will 
support what you're doing: building a switch using software and general-purpose 
hardware, instead of just buying a fixed-function hardware device. There's no 
requirement to use pfSense on the left-hand system, in your diagram. (It will 
do a fine job, however.) 
-- 
-Adam Thompson [email protected] Cell: +1 204 291-7950
 Fax: +1 204 489-6515 

_______________________________________________ 
List mailing list 
[email protected] 
http://lists.pfsense.org/mailman/listinfo/list 

_______________________________________________
List mailing list
[email protected]
http://lists.pfsense.org/mailman/listinfo/list

Reply via email to