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Bug #1572

DHCP + MAC spoofing leads to link cycling

Added by Chris Buechler over 8 years ago. Updated almost 8 years ago.

Status:
Resolved
Priority:
Normal
Assignee:
-
Category:
Operating System
Target version:
-
Start date:
06/01/2011
Due date:
% Done:

100%

Estimated time:
Affected Version:
Affected Architecture:

Description

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.

Associated revisions

Revision 49db607f (diff)
Added by Jim Pingle about 8 years ago

Prevent link cycling when spoofing mac + DHCP. Fixes #1572

Revision 0389f034 (diff)
Added by Jim Pingle about 8 years ago

Prevent link cycling when spoofing mac + DHCP. Fixes #1572

History

#1 Updated by Evgeny Yurchenko over 8 years ago

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

#2 Updated by Daniel Bernhardt over 8 years ago

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)

#3 Updated by Basel G. over 8 years ago

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?

#4 Updated by Chris Buechler over 8 years ago

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.

#5 Updated by Johnny Good over 8 years ago

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

#6 Updated by Derrick Brashear over 8 years ago

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".

#7 Updated by Seth Mos about 8 years ago

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.

#8 Updated by Jim Pingle about 8 years ago

  • Status changed from New to Feedback
  • % Done changed from 0 to 100

#10 Updated by Justin Mitchell about 8 years ago

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

#11 Updated by Justin Mitchell about 8 years ago

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

#12 Updated by Chris Buechler almost 8 years ago

  • Status changed from Feedback to Resolved

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