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DFM Name resolution and HSRP/GLBP

Nigel Bowden
Level 2
Level 2

Hi,

I have a couple of queries regarding DFM 2.0.8.

I understand that DFM needs to be able to resolve names via DNS or a local hosts file to correctly name devices in DFM.

Can anyone tell me if DFM also needs to be able to reverse lookup all IP addresses on a device to perform correctly ? I've noticed that devices that have a large number of IP interfaces (e.g. VLAN interfaces) take a lot longer to change from Learning to Known mode in DFM and wondered if it is a name resolution issue. I've had instances where 6500's can take hours to change state when they have large numbers of IP addresses.

Also, DFM 2.0.8 seems to handle HSRP interfaces OK, but I have just installed it on a network which has GLBP and DFM reports many duplicate addresses. Is there anyway to stop this ?

Regards

Nigel.

3 Replies 3

Joe Clarke
Cisco Employee
Cisco Employee

I'll answer the last question first. Currently, DFM does not support GLBP (see CSCee02681). The workaround is to unmanage the affected interfaces, but this is generally unacceptable. There is no ETA on when this will be supported.

The only resolution DFM should be doing is for the name of the device. Beyond that, DFM will do a lot of polling to determine device inventory, instrumentation, and initial health. The more interfaces, the longer this will take.

Thanks very much for the response, much appreciated ! :)

In terms of the name, do you mean that a single hosts files entry (or DNS forward & reverse lookup) is sufficient (i.e. the loopback address of the device against the device name) ? The only reason I ask is that apps like HP OV work much better if you have reverse DNS lookups or multiple host file entries so that all IP interfaces can be resolved.

Thanks again.

Nigel.

It really depends on how you've configured the other LMS apps. If you are setup for loopback resolution, then you should use the oper up loopback interface with the lowest ifIndex, and make sure its IP and hostname are symmetrically resolable. Then use that IP and hostname in every management application. That IP should also be your trap and syslog source address.

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