pfSense

Do you know the way to reproduce it? I can't see this behavior...

I encountered the same problem. Enabling MAC spoofing on WAN Interface using DHCP will instantly trigger link cycling (link up: ~5 seconds, link down: ~5 seconds). As mentioned by the original poster only a reboot fixes the problem temporarily (changing the port oper status (pulling the plug) will trigger link cycling again).

Confirmed with 2.0-RC3 (as of 21.06.2011)

I'm facing the same problem with the latest snapshots for the past 4 days, also "Deny unkown hosts" doesn't do as it says...

is there a snapshot to downgrade to that is working?

this has never worked in any 8.x base versions, it's a problem in FreeBSD 8.x. It's intermittent, I ran that way for 2 years and only hit it twice. It's something we'll report upstream later if it hasn't already been fixed in 9, that's why this is here.

Chris Buechler wrote:

If MAC spoofing is enabled on an interface that is a DHCP client, in some circumstances it can get itself into a mess with cycling the link on the NIC repeatedly, preventing the system from functioning. A release/renew is typically enough to trigger it. Rebooting is the only way to fully clean that up that I've found at least.

I just wanted to confirm that I have exact same issue. Here's the link to my forum post.
http://forum.pfsense.org/index.php/topic,39074.0.html

I now wonder if it's also this:
http://forum.pfsense.org/index.php/topic,36643.0.html
if so, I can reproduce but alas not on demand. it happens "eventually".

I have one installs where this happens too, I've stopped the flapping by putting by putting a switch in between the cable modem and pfSense.

That works around it but is hideous. In 2.1 I've disabled a interface_bring_down() I found which may or may not stop it.

Applied in changeset 49db607f186c37ad48b25640184051a6ae205ff4.

I'm having a similar issue to this so I wonder if it's linked. I'm running my WAN interface in DHCP. If I try and change the Speed and Duplex OR the MTU, the WAN interface will cycle up and down without stop. The only way to return to normal is to set the Speed and Duplex to nothing other than "default". Also the MTU option must be completely BLANK. I'm running pfsense 2.0 (i386) using the "EXPI9402PT 10/ 100/ 1000Mbps PCI-Express PRO/1000 PT Dual Port Server Adapter" NIC

Justin Mitchell wrote:

I'm having a similar issue to this so I wonder if it's linked. I'm running my WAN interface in DHCP. If I try and change the Speed and Duplex OR the MTU, the WAN interface will cycle up and down without stop. The only way to return to normal is to set the Speed and Duplex to nothing other than "default". Also the MTU option must be completely BLANK. I'm running pfsense 2.0 (i386) using the "EXPI9402PT 10/ 100/ 1000Mbps PCI-Express PRO/1000 PT Dual Port Server Adapter" NIC.

Forgot to mention that the system is running the EM driver for this NIC