HSRP explaination needed

[cisco24x7]

can someone with extensive HSRP experience tell me what this message means?

R1 F1/0 ip address 192.168.1.2/24

R2 E0/1 ip address is 192.168.1.3/24

HSRP ip address is 192.168.1.1

Linux host ip address is 192.168.1.13

Everything is connected to the same switch with VLAN 10.

config on R1 F1/0:

interface FastEthernet1/0

ip address 192.168.1.2 255.255.255.0

load-interval 30

duplex auto

speed auto

standby 10 ip 192.168.1.1

standby 10 priority 110

standby 10 preempt

standby 10 authentication cisco123

standby 10 name group1

Config on R2 E0/1:

interface Ethernet0/1

ip address 192.168.1.3 255.255.255.0

half-duplex

standby 10 ip 192.168.1.1

standby 10 priority 105

standby 10 preempt

standby 10 authentication cisco123

standby 10 name group1

R1#sh stand b

P indicates configured to preempt.

|

Interface Grp Prio P State Active Standby Virtual IP

Fa1/0 10 110 P Active local 192.168.1.3 192.168.1.1

R1#

R2#sh stand b

P indicates configured to preempt.

|

Interface Grp Prio P State Active Standby Virtual IP

Et0/1 10 105 P Standby 192.168.1.2 local 192.168.1.1

R2#

Everything appears to be fine. However, tcpdump on the Linux host reveals the following:

[root@LinuxES-lab2 root]# tcpdump -nnn -i eth0 net 224.0.0.2 | grep unknown

tcpdump: listening on eth0

21:52:05.800864 192.168.1.3.1985 > 224.0.0.2.1985: HSRPv0-unknown (3) 16: state=initial group=2 [|hsrp] [tos 0xc0] [ttl 1]

21:52:33.909982 192.168.1.3.1985 > 224.0.0.2.1985: HSRPv0-unknown (3) 16: state=initial group=2 [|hsrp] [tos 0xc0] [ttl 1]

21:53:00.741247 192.168.1.3.1985 > 224.0.0.2.1985: HSRPv0-unknown (3) 16: state=initial group=2 [|hsrp] [tos 0xc0] [ttl 1]

21:53:28.682443 192.168.1.3.1985 > 224.0.0.2.1985: HSRPv0-unknown (3) 16: state=initial group=2 [|hsrp] [tos 0xc0] [ttl 1]

21:53:57.985459 192.168.1.3.1985 > 224.0.0.2.1985: HSRPv0-unknown (3) 16: state=initial group=2 [|hsrp] [tos 0xc0] [ttl 1]

21:54:26.639632 192.168.1.3.1985 > 224.0.0.2.1985: HSRPv0-unknown (3) 16: state=initial group=2 [|hsrp] [tos 0xc0] [ttl 1]

21:54:54.208061 192.168.1.3.1985 > 224.0.0.2.1985: HSRPv0-unknown (3) 16: state=initial group=2 [|hsrp] [tos 0xc0] [ttl 1]

22:02:32.895394 192.168.1.2.1985 > 224.0.0.2.1985: HSRPv0-hello 20: state=active group=10 addr=192.168.1.1 [tos 0xc0] [ttl 1]

22:02:32.995694 192.168.1.3.1985 > 224.0.0.2.1985: HSRPv0-hello 20: state=standby group=10 addr=192.168.1.1 [tos 0xc0] [ttl 1]

22:02:35.895322 192.168.1.2.1985 > 224.0.0.2.1985: HSRPv0-hello 20: state=active group=10 addr=192.168.1.1 [tos 0xc0] [ttl 1]

22:02:35.996345 192.168.1.3.1985 > 224.0.0.2.1985: HSRPv0-hello 20: state=standby group=10 addr=192.168.1.1 [tos 0xc0] [ttl 1]

As you can see R2 is sending out HSRP0-unknown. What does this mean? I see this

in both my lab and production environment. Is this something I should be concerned

with? Can someone explain this?

[cisco24x7]

It made no difference. Any other suggestions?

[John Blakley]

Can you post the debugs from R1? In your R2 post, I don't see where it's trying to find a group 2, but I see it in your tcpdump. You also said that this one system is going into a 3750 that's configured as a L2 switch. So, you have:

linux --> switch --> router

There's nothing in-between?

[Richard Burts]

John

While it might be interesting to see debugs from R1 the tcpdump output clearly shows the source address as being from R2.

David

I am quite puzzled that the tcpdump is reporting these packets but that the debug from R2 does not show R2 sending them. I am beginning to think that some other device (and perhaps some other utility) looking at the traffic might be helpful.

[edit] it is also very puzzling that the mystery packets are for HSRP group 2 but there is no configuration of group 2 on R2.

HTH

Rick

[cisco24x7]

Trust me when I say that there are only 3

devices connected to the L2 switch. I know

because I removed everything else. Still have

the same issue.

[cisco24x7]

Think of the switch as a dumb HUB. All three

devices, R1, R2 and linux connect to the same

VLAN 1 on the switch.

[insccisco]

How are you doing with this issue?

still standing?

[cisco24x7]

yes, it is still an issue. Any ideas on how

to stop R2 from sending out "unknown" HSRP-v0?

[insccisco]

No, I actually just started playing with HSRP. But if it looks like all is working and this is clearly an unexpected behavior, I would suggest to check at the IOS bug releases, perhaps you're hitting one and by upgrading the IOS will "fix" the issue....

[cisco24x7]

Anymore ideas anyone?

[pfillips11]

What does show stand show on both R1 and R2?

If R2 is really sending something then it should show the initial HSRP state.

The debugs somehow do not indicate that its sending anything.

[crow930us]

How often do you see these messages? Are they only at startup or do they occur over a certain period of time or after you finish some configuration changes?

21:54:26.639632 192.168.1.3.1985 > 224.0.0.2.1985: HSRPv0-unknown (3) 16: state=initial group=2 [|hsrp] [tos 0xc0] [ttl 1]

The reason I ask is because the initial phase is when HSRP either first comes up on an interface or when there is a configuration change done on an interface. Obviously the HSRPv0-unknown would be there if HSRP is first coming up. The default group for HSRP is 0 and you have a configured HSRP group of 10, so I'm not sure where the group=2 part is coming from.

The last 4 lines of output is where the two devices decide which is going to be the active router and the standby router, which is verified by the priorities assigned on each interface.

I didn't see anyone mention anything about the different states that HSRP goes through when it first starts up. To me the HSRPv0-unknown would be a normal message when the interface is first configured with HSRP or a change on the interface.