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Silver

HSRP explaination needed

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?

  • LAN Switching and Routing
25 REPLIES
Hall of Fame Super Silver

Re: HSRP explaination needed

David

While I do not have a good explanation about what would cause this I believe that it is not something to worry about. The messages (and the show standby output) indicate that the configured HSRP is working as expected. I am not clear why R2 would generate these messages. But I notice that they are the initiation messages for group 2. I do not see anything that would cause the router to do anything about group 2, or why R2 would do it and not R1.

I am also puzzled about your output. If your command included this:

net 224.0.0.2 | grep unknown

then how do you get this;

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]

since it does not include the string unknown?

HTH

Rick

Silver

Re: HSRP explaination needed

"The messages (and the show standby output) indicate that the configured HSRP is working as expected."

How can you be sure? Just because it shows

that everything looks correct does not mean

that there are not issues. I see random

packetloss on my network which may or may not

berelated to this but I need to rule this out

as a potential cause.

To anwer your 2nd question, I have two

different tcpdump "tcpdump -nnn -i eth0 net 224.0.0.2" and "tcpdump -nnn -i eth0 net 224.0.0.2 | grep unknown" and combine the

output.

Silver

Re: HSRP explaination needed

Hi

As Rick already stated, it seems that there is a config like "standby 2 ". Perhaps a config left from earlier, that is not used anymore.

Please share the output of "show running interface Ethernet0/1", taken from R2.

/Mikael

Silver

Re: HSRP explaination needed

R2#sh run int e0/1

Building configuration...

Current configuration : 212 bytes

!

interface Ethernet0/1

ip address 192.168.1.3 255.255.255.0

half-duplex

standby 10 ip 192.168.1.3

standby 10 priority 105

standby 10 preempt

standby 10 authentication cisco123

standby 10 name group1

end

R2#

Re: HSRP explaination needed

I agree with everyone else. It seems as though it's still looking for an old group 2. Maybe you should delete the HSRP config from R2 and recreate. Do you have any other HSRP configs on any of the other interfaces on this router?

HTH,

John

HTH, John *** Please rate all useful posts ***
Silver

Re: HSRP explaination needed

"Do you have any other HSRP configs on any of the other interfaces on this router?"

NO

I performed the following on R2:

interface E0/1

no stand 10

no ip address

shut

(wait for 60 seconds)

ip address 192.168.1.3 255.255.255.0

standby 10 ip 192.168.1.3

standby 10 priority 105

standby 10 preempt

standby 10 authentication cisco123

standby 10 name group1

no shut

still has the same issue. Reboot ther router

several times with the same result.

Re: HSRP explaination needed

Are you connected to a layer 3 switch that has hsrp enabled on it? Tcpdump is getting it from somewhere. What happens if you debug hsrp on the router? Do you see the same error messages?

John

HTH, John *** Please rate all useful posts ***
Silver

Re: HSRP explaination needed

everything is connected to a lay-2 3750 switch.

The switch is operating only in L2 mode. No L3.

tcpdump on the linux is getting it from the

router because this is multicast address.

Therefore, the linux server is definitely

seeing it from R2.

"debug stand events" and "debug stand packets"

shows me exactly what I am seeing on the Linux

box, minus the "HSRPv0-unknown"

Silver

Re: HSRP explaination needed

more tips anyone? Thanks.

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