Skip to content
View in the app

A better way to browse. Learn more.

Unraid

A full-screen app on your home screen with push notifications, badges and more.

To install this app on iOS and iPadOS
  1. Tap the Share icon in Safari
  2. Scroll the menu and tap Add to Home Screen.
  3. Tap Add in the top-right corner.
To install this app on Android
  1. Tap the 3-dot menu (⋮) in the top-right corner of the browser.
  2. Tap Add to Home screen or Install app.
  3. Confirm by tapping Install.

arp spam on router

Featured Replies

One of my servers has started flooding my separate pfsense router with what appears to be arp spam?

 

The server seems to be switching back and forth between 2 of the 4 ethernet ports shown by their mac addresses:

 

Mar 8 01:12:37	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:12:40	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:13:17	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:13:20	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:13:58	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:14:00	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:14:27	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:14:30	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:14:58	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:15:00	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:15:27	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:15:30	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:15:57	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:16:00	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:16:28	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:16:29	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:16:58	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:16:59	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:17:27	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:17:29	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:17:57	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:17:59	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:18:27	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:18:29	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:18:57	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:19:00	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:19:31	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:19:35	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:20:01	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:20:03	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:20:31	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:20:33	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:21:00	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:21:03	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:21:31	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:21:33	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:22:01	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:22:04	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:22:31	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:22:35	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:23:01	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:23:04	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:23:31	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:23:33	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:24:46	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:24:50	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:25:37	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:25:39	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0
Mar 8 01:26:27	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:ea to 00:26:55:2a:2b:e4 on re0
Mar 8 01:26:29	kernel		arp: 192.168.1.121 moved from 00:26:55:2a:2b:e4 to 00:26:55:2a:2b:ea on re0

 

I have one of my other identical servers which is powered on at the same time does no exhibit this behavior. Both are set for balance-alb.

 

Thoughts?

 

I'm guessing the bond is flapping: But maybe the kernel is not logging it?

From the bonding documnentation about balance-alb

Quote

When a link is reconnected or a new slave joins the bond the receive traffic is redistributed among all active slaves in the bond by initiating ARP Replies with the selected MAC address to each of the clients. The updelay parameter (detailed below) must be set to a value equal or greater than the switch's forwarding delay so that the ARP Replies sent to the peers will not be blocked by the switch.

 

  • Author

when I take the one of the two ports it is alternating between down, it stops the arp messages for a while, but eventually starts the same activity on another port.

 

I'm going to try switching the bonding mode and see if that changes it. still curious why it happens on 1 server but not the other.

  • Author

since changing to active backup, arp spam has stopped, but i'm not able to exceed more than 1gb throughput now.... guess it's time to just buy a 10gbe switch and move on.

Archived

This topic is now archived and is closed to further replies.

Account

Navigation

Search

Search

Configure browser push notifications

Chrome (Android)
  1. Tap the lock icon next to the address bar.
  2. Tap Permissions → Notifications.
  3. Adjust your preference.
Chrome (Desktop)
  1. Click the padlock icon in the address bar.
  2. Select Site settings.
  3. Find Notifications and adjust your preference.