SOLVED DHCP Leak issue - FreeNAS 11

[Luc De Bolle]

Dear Forum users,
I am having a network issue with a FreeNAS installation.

The FreeNAS is installed an a HP Gen8 MicroServer (system info below).
The NAS is connected to 2 different networks, both equipped with their own DHCP server.
192.168.124.0/24 Network1 (DHCP server: IPCop FW, version 2.x)
192.168.13.0/24 Network2 (DHCP Server: OpenWRT on TPLink HW)
The NAS itself uses a fixed IP address for both networks.

I have a laptop that connects to Network1 via a wired connection and to Network2 via the Wireless adapter.
This laptop uses DHCP for both networks.

I have the impression that DHCP traffic leaks through the NAS.
Several times I got a Network2 address via the wired connection (while I am physically connected to Network1).
When I do a release/renew sequence in windows, I get an address in the correct range.

I have one fixed route in the FreeNAS defined for VPN access address range (192.168.124.0/24 to 10.x.y.z range)

At this point, I do not know if it is a Windows or FreeNAS issue.
I just know that I never had this issue until I added the FreeNAS to the setup.

I searched the forum, but could see this, or a similar issue.

Any suggestions are welcome.

Thanks,
Best regards,
Luc

FreeNAS info:
Server model Model Specs
Model: ProLiant MicroServer Gen8
Xeon® Quad-Core E3-1220Lv2 2.30 GHz
Processor Cache 3 MB
Chipset Intel C204
DDR3 SDRAM 8 GB
Interfaces
4 non hot-swap HD bays
5 x USB 2.0
2 x USB 3.0

2 x RJ-45

1 x VGA

Harddisks: 4 x Nas Hdd Wd Red 2TB 3.5in SATA 3 Intellipower 64MB

FreeNAS System Information
Build FreeNAS-11.0-RELEASE (a2dc21583)
Platform Intel(R) Xeon(R) CPU E3-1220L V2 @ 2.30GHz
Memory 7992MB
Load Average 1.07, 1.05, 1.01

 

[m0nkey_]

You likely have a bridge interface configured on your FreeNAS server.

Secondly, make your DHCP server authoritative. That should help to prevent rogue DHCP servers.

 

[Luc De Bolle]

Thank you mOnkey_, I will check those points tonight!
(it feels strange to call someone mOnkey_ ...)

 

[Luc De Bolle]

Thank you mOnkey_, I will check those points tonight!
(it feels strange to call someone mOnkey_ ...)

Hi mOnkey,
Your tip was spot-on!
I had been playing with the VM functionality and this must have added the bridge behind the scenes...
All seems fine now.
Thanks again