03-22-2013 04:31 PM - edited 03-07-2019 12:26 PM
Hi, everyone.
Recently customers insisted that ping failed (for a while) from their own NMS system to host. And Cisco HSRP are working in the middle of their cloud.
Question) 00:00:0c:9f:f7:6e can be HSRP Virtual MAC?? In my understanding, 0000.0c07.ac0a is HSRP Virtual MAC though.
0000.0c (Vendor Code)
07.ac (Well-known HSRP Code)
0a (HSRP Group number 10 in hex)
Information related to HSRP(version2, IPv4 group 1902) by capture.
[1] Active IP : 33.136.2.2 (Cisco_9f:f6:62). Cisco=54:75:d0
[2] Standby IP : 33.136.2.3 (Cisco_ae:27:99) Cisco=54:75:d0
[3] Virtual IP : 33.136.2.1 (All hosts' Gateway IP address)
By capture, host received ping request and can't response for a while and keep responding.
During no responding, there are ARP reply between Cisco and host.
-->> Cisco_9f:f7:6e (source) Somevend_b3:83:00 ARP 33.136.2.1 at 00:00:0c:9f:f7:6e
-->> Cisco_9f:f7:6e = 00:00:0c:9f:f7:6e.
Small Question) Ping from NMS and ping from local server have different source. Is it possible?
Ping from NMS has source Active(HSRP) 54:75:d0:9f:f6:62
Ping from local server has source Standby(HSRP) 54:75:d0:ae:27:99
Many Thanks!!!
Jeff D. LEE
Solved! Go to Solution.
03-22-2013 05:10 PM
Hello,
Question) 00:00:0c:9f:f7:6e can be HSRP Virtual MAC??
Yes. The HSRP Version 2 uses a new MAC address range 0000.0C9F.F000 to 0000.0C9F.FFFF. Your MAC address corresponds to the standby group number 0x76e = 1902. For more information, see:
http://www.cisco.com/en/US/docs/ios/12_3t/12_3t4/feature/guide/gthsrpv2.pdf
http://www.cisco.com/en/US/tech/tk648/tk362/technologies_q_and_a_item09186a00800a9679.shtml#q34
In my understanding, 0000.0c07.ac0a is HSRP Virtual MAC though
This is true for HSRP Version 1. Version 2 uses a different MAC address prefix as noted above.
Small Question) Ping from NMS and ping from local server have different source. Is it possible?
Ping from NMS has source Active(HSRP) 54:75:d0:9f:f6:62
Ping from local server has source Standby(HSRP) 54:75:d0:ae:27:99
I apologize, I do not understand this. Neither of mentioned MAC addresses corresponds to HSRP MAC address. Perhaps you could clarify this with a picture of your topology.
Best regards,
Peter
03-22-2013 04:45 PM
Hello!
What kind of devices are these and what is the version of code they are running?
Dave
07-30-2015 11:46 PM
problem solved!
Thank you
the problem was there was a VACL on one of the distribution switches which was there for long before we introduced these new set of VLAN ranges.
vlan access-map PTS-STUDENT VLan-list 14-15
as soon as i removed this, the hsrp communication resumed
thank you again all!
03-22-2013 05:10 PM
Hello,
Question) 00:00:0c:9f:f7:6e can be HSRP Virtual MAC??
Yes. The HSRP Version 2 uses a new MAC address range 0000.0C9F.F000 to 0000.0C9F.FFFF. Your MAC address corresponds to the standby group number 0x76e = 1902. For more information, see:
http://www.cisco.com/en/US/docs/ios/12_3t/12_3t4/feature/guide/gthsrpv2.pdf
http://www.cisco.com/en/US/tech/tk648/tk362/technologies_q_and_a_item09186a00800a9679.shtml#q34
In my understanding, 0000.0c07.ac0a is HSRP Virtual MAC though
This is true for HSRP Version 1. Version 2 uses a different MAC address prefix as noted above.
Small Question) Ping from NMS and ping from local server have different source. Is it possible?
Ping from NMS has source Active(HSRP) 54:75:d0:9f:f6:62
Ping from local server has source Standby(HSRP) 54:75:d0:ae:27:99
I apologize, I do not understand this. Neither of mentioned MAC addresses corresponds to HSRP MAC address. Perhaps you could clarify this with a picture of your topology.
Best regards,
Peter
03-22-2013 07:56 PM
Hi, Peter
Really thanks! It helps alot.
Jeff
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