MAC keeps changing in arp

slam

Active Member
Apr 10, 2012
17
0
41
Code:
Oct  1 17:24:37 freenas kernel: arp: 192.168.42.20 moved from e0:69:95:90:9c:aa to 84:2b:2b:c2:5e:7a on bge0
Oct  1 17:39:47 freenas kernel: arp: 192.168.42.20 moved from 84:2b:2b:c2:5e:7a to e0:69:95:90:9c:aa on bge0
Oct  1 17:40:45 freenas kernel: arp: 192.168.42.20 moved from e0:69:95:90:9c:aa to 84:2b:2b:c2:5e:7a on bge0

I keep getting the above message(s) in my (FreeNAS) console, should I be concerned? Is there a way to stop it from happening?

192.168.42.20 = One Node (of 2 Node) Proxmox cluster
 
Last edited:
is 192.168.42.20 a physical machine or a vm? your freenas box is reporting that the MAC address of 192.168.42.20 is changing.
 
is 192.168.42.20 a physical machine or a vm? your freenas box is reporting that the MAC address of 192.168.42.20 is changing.

It's physical, 1-Node of a 2-Node Proxmox cluster.

Here's the ifconfig:

Code:
eth0      Link encap:Ethernet  HWaddr 84:2b:2b:c2:5e:7a          
          inet6 addr: fe80::862b:2bff:fec2:5e7a/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:13926 errors:0 dropped:0 overruns:0 frame:0
          TX packets:13780 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:4075853 (3.8 MiB)  TX bytes:5665640 (5.4 MiB)
          Interrupt:21 Memory:f7fe0000-f8000000


lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:1177 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1177 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:328807 (321.1 KiB)  TX bytes:328807 (321.1 KiB)


tap201i0  Link encap:Ethernet  HWaddr 7a:61:b1:68:61:7b
          inet6 addr: fe80::7861:b1ff:fe68:617b/64 Scope:Link
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:330 errors:0 dropped:0 overruns:0 frame:0
          TX packets:670 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:500
          RX bytes:74558 (72.8 KiB)  TX bytes:122097 (119.2 KiB)


venet0    Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
          inet6 addr: fe80::1/128 Scope:Link
          UP BROADCAST POINTOPOINT RUNNING NOARP  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:3 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)


vmbr0     Link encap:Ethernet  HWaddr 84:2b:2b:c2:5e:7a
          inet addr:192.168.42.20  Bcast:192.168.42.255  Mask:255.255.255.0
          inet6 addr: fe80::862b:2bff:fec2:5e7a/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:12766 errors:0 dropped:0 overruns:0 frame:0
          TX packets:12351 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:3735667 (3.5 MiB)  TX bytes:5537166 (5.2 MiB)
 
looks like you have something else on the network that may have the same IP address, do you have DHCP on your network? if you do I'd change the range to be from 192.168.42.40 upwards or remove the 192.168.42.10 to 192.168.42.30 section from the DHCP pool.
 
I have DHCP, would removing the 192.168.42.40 from the lease help? I'm also doing bridging and vlan tagging on the proxmox box, I would if that also has anything to do with it.

edit/update: It's looking more like it's another box with duplicate ip on the network as I turned off the proxmox box still able to ping 192.168.42.40.
 
Last edited:
its more likely that something else on the network is being given the 192.168.42.20 IP address if its still in the lease pool. That would definately cause issues.

If its a small network that you're managing i'd check to find out what machine and refresh its dhcp lease to prevent it from causing any more grief :)

All my DHCP ranges have a set amount of addresses to assign and a big range for static ips:

Example:
192.168.1.1 - Router
192.168.1.5-10 - Switches
192.168.1.11-40 - Physical Servers
192.168.1.50-100 - Virtual Servers
192.168.1.150-200 - DHCP Pool
 
It's a pretty big network, so I have no idea who or which machine has that IP. Hopefully I can reclaim it, else my Proxmox cluster will bjork and I heard it's quite difficult to reconfigure the cluster. :(

Thanks for the tip about the IP ranges, I'll keep that in mind the next time I do a redesign of my network. :)
 
I have the same issue where freenas console shows arp move messages for 192.168.100.42 swapping between 3 different MAC addresses.
The 3 MAC addresses are the 3 NICS on my Proxmox 2.1 host machine.
eth0=192.168.100.42=vmbr0
eth1=192.168.100.53=vmbr1
eth2=192.168.100.54=vmbr2
I am not using bonding.
I am using this freenas storage for vzdump and there doesn't seem to be any problems.
Is this normal behaviour?
 
Hello.
I have the same problem with a nas4free nas that I want to use for vm storage on iscsi.
The proxmox host has 2 network interfaces on different subnet (192.168.200.0 and 192.168.201.0) connected with a dedicated switch to the nas4free server.

This is the proxmox network config

Code:
eth0      Link encap:Ethernet  HWaddr 00:1e:4f:20:32:3b            inet6 addr: fe80::21e:4fff:fe20:323b/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1032346 errors:0 dropped:0 overruns:0 frame:0
          TX packets:940185 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:1025941053 (978.4 MiB)  TX bytes:96790027 (92.3 MiB)


eth2      Link encap:Ethernet  HWaddr 00:15:17:63:56:4e  
          inet addr:192.168.200.30  Bcast:192.168.200.255  Mask:255.255.255.0
          inet6 addr: fe80::215:17ff:fe63:564e/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:84037148 errors:0 dropped:568 overruns:0 frame:0
          TX packets:55748736 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:88598257398 (82.5 GiB)  TX bytes:39459734170 (36.7 GiB)
          Interrupt:16 Memory:fc3e0000-fc400000 


eth3      Link encap:Ethernet  HWaddr 00:15:17:63:56:4f  
          inet addr:192.168.201.30  Bcast:192.168.201.255  Mask:255.255.255.0
          inet6 addr: fe80::215:17ff:fe63:564f/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:89541611 errors:0 dropped:12933 overruns:0 frame:0
          TX packets:55686388 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:94854825994 (88.3 GiB)  TX bytes:39316043550 (36.6 GiB)
          Interrupt:17 Memory:fc3a0000-fc3c0000

On the nas4free server I see

Code:
arp: 192.168.200.30 moved from 00:15:17:63:56:4e to 00:15:17:63:56:4f on em0
arp: 192.168.201.30 moved from 00:15:17:63:56:4f to 00:15:17:63:56:4e on em1
arp: 192.168.200.30 moved from 00:15:17:63:56:4f to 00:15:17:63:56:4e on em0
arp: 192.168.201.30 moved from 00:15:17:63:56:4e to 00:15:17:63:56:4f on em1
arp: 192.168.200.30 moved from 00:15:17:63:56:4e to 00:15:17:63:56:4f on em0
arp: 192.168.201.30 moved from 00:15:17:63:56:4f to 00:15:17:63:56:4e on em1

so the ip address are exchanged between the two interfaces.

What could cause this problem?
 
Almost 8 years later and there is no reply to an issue that presents itself today. I'm having the same issue. Does anybody know what the cause is? If so, what is the fix?

Thanks
 
Almost 8 years later and there is no reply to an issue that presents itself today. I'm having the same issue. Does anybody know what the cause is? If so, what is the fix?

Thanks
Well this problem exist since ip has been invented ;) you have 2 mac address on your network with same ip address .
 
Well this problem exist since ip has been invented ;) you have 2 mac address on your network with same ip address .
No I don't. I've even gone so far as to change the addresses. I've scanned subnets with Wireshark and Zenmap. No duplicates at all.

What I'm experiencing is terrible speed, the MAC address changes every nth of a second, and now I'm seeing LAN traffic in the DMZ and vise-versa in my Pfsense logs. The 2 MAC addresses map to both my LAN and DMZ.


ip link show output
Note: (Bold MAC addresses are the ones that the PVE host flip-flop between)

ip link show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr0 state UP mode DEFAULT group default qlen 1000
link/ether 78:2b:cb:5e:94:4f brd ff:ff:ff:ff:ff:ff
altname enp1s0f0
3: eno2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr2 state UP mode DEFAULT group default qlen 1000
link/ether 78:2b:cb:5e:94:51 brd ff:ff:ff:ff:ff:ff
altname enp1s0f1
4: eno3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr3 state UP mode DEFAULT group default qlen 1000
link/ether 78:2b:cb:5e:94:53 brd ff:ff:ff:ff:ff:ff
altname enp2s0f0
5: eno4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr4 state UP mode DEFAULT group default qlen 1000
link/ether 78:2b:cb:5e:94:55 brd ff:ff:ff:ff:ff:ff
altname enp2s0f1
7: vmbr3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
link/ether 78:2b:cb:5e:94:53 brd ff:ff:ff:ff:ff:ff
8: vmbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
link/ether 78:2b:cb:5e:94:4f brd ff:ff:ff:ff:ff:ff
9: vmbr2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
link/ether 78:2b:cb:5e:94:51 brd ff:ff:ff:ff:ff:ff
10: vmbr4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
link/ether 78:2b:cb:5e:94:55 brd ff:ff:ff:ff:ff:ff
11: tap100i0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vmbr4 state UNKNOWN mode DEFAULT group default qlen 1000
link/ether aa:77:6f:58:f0:54 brd ff:ff:ff:ff:ff:ff
12: tap100i1: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vmbr3 state UNKNOWN mode DEFAULT group default qlen 1000
link/ether e2:ca:6d:ab:39:8d brd ff:ff:ff:ff:ff:ff
13: tap100i2: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vmbr2 state UNKNOWN mode DEFAULT group default qlen 1000
link/ether ba:77:96:2c:76:49 brd ff:ff:ff:ff:ff:ff
14: veth105i0@if2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master vmbr3 state UP mode DEFAULT group default qlen 1000
link/ether fe:4c:2e:73:62:bb brd ff:ff:ff:ff:ff:ff link-netnsid 0

ip neigh output;
Note: (vmbr0 --> PVE Host, vmbr2 --> DMZ, 192...1 --> PFsense, 192...254 --> Management laptop)

192.168.1.1 dev vmbr2 lladdr ce:6f:cc:2a:c3:a0 STALE
192.168.1.1 dev vmbr0 lladdr ce:6f:cc:2a:c3:a0 REACHABLE
192.168.1.254 dev vmbr0 lladdr 10:0b:a9:08:8b:98 REACHABLE
192.168.1.254 dev vmbr2 lladdr 10:0b:a9:08:8b:98 STALE
fe80::c81e:52ff:fe38:af95 dev vmbr2 lladdr ca:1e:52:38:af:95 STALE
fe80::14e6:48ff:fef7:402c dev vmbr2 lladdr 16:e6:48:f7:40:2c STALE
fe80::401a:a90e:79f:a326 dev vmbr2 lladdr 90:70:65:d0:8e:ae STALE
fe80::7a2b:cbff:fe5e:9453 dev vmbr0 lladdr 78:2b:cb:5e:94:53 STALE
fe80::ac86:32ff:feed:3958 dev vmbr2 lladdr ae:86:32:ed:39:58 STALE
fe80::8c79:3ff:fe8d:5584 dev vmbr2 lladdr 8e:79:03:8d:55:84 STALE
fe80::7a4b:87ff:fe46:47e dev vmbr2 lladdr 78:4b:87:46:04:7e STALE
fe80::9417:3dff:fe66:5e61 dev vmbr2 lladdr 96:17:3d:66:5e:61 STALE
fe80::7a2b:cbff:fe5e:9453 dev vmbr2 lladdr 78:2b:cb:5e:94:53 STALE
fe80::120b:a9ff:fe08:8b98 dev vmbr2 lladdr 10:0b:a9:08:8b:98 STALE
fe80::217:10ff:fe90:c58f dev vmbr4 lladdr 00:17:10:90:c5:8f router STALE
fe80::a53f:c321:eefd:647c dev vmbr2 lladdr 10:98:c3:c3:8b:c2 STALE

Thanks
V
 
This looks like the Problem of Microsoft Nic Teaming. When you create a MS Nic Team, the teaming interface becomes 1 of the MAC from any Member. When traffic goes over another Member, any Switches register a MAC flapping. Workaround at Windows, give the teaming Interface a unique MAC.

Please check your Network Configs for similar things.
 
can you send your /etc/network/interfaces of the proxmox host ?

# network interface settings; autogenerated
# Please do NOT modify this file directly, unless you know what
# you're doing.
#
# If you want to manage parts of the network configuration manually,
# please utilize the 'source' or 'source-directory' directives to do
# so.
# PVE will preserve these directives, but will NOT read its network
# configuration from sourced files, so do not attempt to move any of
# the PVE managed interfaces into external files!

auto lo
iface lo inet loopback

auto eno1
iface eno1 inet manual
#Management IF

auto eno2
iface eno2 inet manual
#Dedicated DMZ

auto eno3
iface eno3 inet manual
#Dedicated LAN

auto eno4
iface eno4 inet manual
#Dedicated WAN

auto vmbr3
iface vmbr3 inet manual
gateway 192.168.1.1
bridge-ports eno3
bridge-stp off
bridge-fd 0
bridge-vlan-aware yes
bridge-vids 2-4094
#brLAN

auto vmbr0
iface vmbr0 inet static
address 192.168.1.12/24
bridge-ports eno1
bridge-stp off
bridge-fd 0
#PVE Default

auto vmbr2
iface vmbr2 inet static
address 10.19.36.2/24
bridge-ports eno2
bridge-stp off
bridge-fd 0
#brDMZ

auto vmbr4
iface vmbr4 inet manual
bridge-ports eno4
bridge-stp off
bridge-fd 0
#brWAN
 

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