My goal is to build a redundant pfSense cluster (as described in this article : http://doc.pfsense.org/index.php/Configuring_pfSense_Hardware_Redundancy_(CARP)

The problem is that i only have 2 physical network interfaces on the server and the tutorial suggests to have 3 and dedicated one for the intra-cluster replication (interface SYNC).

I tried the trick of assigning a different IP to one of the interfaces and assign it to a different VLAN.

But when i try

vconfig add eth1:0 3

I get

ERROR: trying to add VLAN #3 to IF -:eth1:0:-  error: Invalid argument

Do you have any idea if this would be possible ? I can't really add a network card on the system; all my slots are full.

  • 6
    pfSense is based on FreeBSD, not even close to Linux. That said, in FreeBSD you simply create vLAN interfaces attached to the physical interfaces, then create a CARP interface attached to the vLAN interfaces. I don't know what all that vconfig stuff is about. It's possible to do all this with just a single interface in the computer. – Chris S Jan 26 '12 at 18:51
  • 3
    BSD systems (including pfSense) don't typically name interfaces ethN:A - My suspicion is that your "invalid argument" is an interface that doesn't exist on your system. What is the output of ifconfig on this host? – voretaq7 Jan 26 '12 at 19:17
  • Yeah you're almost right; i tried the vconfig on an ubuntu system (just for the purpose of the test) but you're right; maybe the vconfig doesn't even exist on freebsd; i'll try on pfSense itself when i get it installed. – Disco Jan 27 '12 at 12:20

If you're actually talking about a Linux system (instead of FreeBSD) then the proper thing to do is:

# vconfig add eth0 3
Added VLAN with VID == 3 to IF -:eth0:-
# ip link show dev eth0.3
104: eth0.3@eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN 
    link/ether 00:ae:f1:21:2a:01 brd ff:ff:ff:ff:ff:ff

That said, usually there's a Better Way of doing so, depending on the distribution in question.


I believe with pfSense, it isn't essential to have a dedicated interface for pfSync, but it is advisable for perforance and security reasons.

As you mentioned a server, you should be able to use Intel Pro 1000MT or 1000PT cards with no issues, and as a bonus, you may find you have no problems using VLANS on those cards if you ever need to add more NICs - both are quite highly recommended for use with pfSense (esp the MT, but they are PCIX only).

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