Disaster Recovery

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  • 1.  Multiple NICs / Multiple Default Gateways

    Posted Jul 31, 2020 03:02 PM

    I have a few VMs that have dual NICs (say NIC1 and NIC2).  Initially, in Windows, I'm only assigning a default gateway to NIC1.

    In my IP Customizations (under Network Mapping) I have it setup to NOT assign a gateway to NIC2.  I left it blank.

    However, after a test or failover, it still ends up assigning a gateway to NIC2.  And, because of this, Windows and my application get confused on which NIC to egress.

    My current workaround is to assign NIC2 a higher metric. 

    Has anyone else seen this problem?  This a bug or how it's intended to work?

    Thanks in advance for your help!



  • 2.  RE: Multiple NICs / Multiple Default Gateways

    Broadcom Employee
    Posted Jul 31, 2020 03:44 PM

    Hi

    If you do not customize a NIC on the recovery site, the NIC continues to use the IP settings from the protected site, and vice versa'

    Please share these information:

    1. What is the version of SRM ?

    2. Have you configured IP customization just at protected site or for both sites

    3.. Please share a screenshot of what configurations are selected and what are left blank



  • 3.  RE: Multiple NICs / Multiple Default Gateways

    Posted Jul 31, 2020 05:34 PM

    Thanks for the reply!

    When our VMs fails over to the , they are in a different subnet.  So I do SRM to change it.

    For the record, I'm using 8.3... but 8.2 also has this issue.

    1. Current versions are the same at both sites:

    SRM 8.3.0.2 (8.3.0.16356494)

    VRA 8.3.0.2 (8.3.0.16284276)

    2.  I configured IP customizations at both sites, both without a gateway defined. 

    3. Screenshots:



  • 4.  RE: Multiple NICs / Multiple Default Gateways

    Posted Oct 22, 2021 07:33 PM

    So, it seems that 8.5.0 still has the same problem.  I did a complete reinstall of SRM too, thinking there may have been some leftovers.  However, it didn't seem to make any difference.  

    I only want 1 of my NICs to be assigned a default gateway.  But no matter what I do, during a failover or test, it assigns one to both NICs.

    Any ideas on how I can overcome this?  Thanks in advance!

    vCenter 6.7.0.50000

    SRM 8.5.0.18710000

    VRA 8.5.0.18598070



  • 5.  RE: Multiple NICs / Multiple Default Gateways

    Posted May 19, 2023 09:57 AM

    Hi,

    I have a customer with the same issue, did you fix it?

    Thank you



  • 6.  RE: Multiple NICs / Multiple Default Gateways

    Posted May 19, 2023 12:36 PM

    There has not been a fix supplied by VMware unfortunately, not that I've seen.  So to overcome this issue, I had to change the metric on the NIC that I don't want using its default gateway and give it a lower priority for routing.  It's not perfect, but it seemed to do the trick.

    First, you need to run a "netstat -rn" to view your network adapters, their Mac addresses, and which index number(s) they've been assigned.

    netstat.png

    In this example, it's "Ethernet Adapter #2" that I don't want using its default gateway.  You will also notice the index number for that is 4.

    The default metric is typically "16".   To increase it, thus giving it a lower priority, you run the following:

    Set-NetIPInterface -InterfaceIndex 4 -InterfaceMetric 100

    Now anytime you create any outgoing network traffic, it will use the interface with the lower metric (higher priority).

    Hopefully, this helps some?



  • 7.  RE: Multiple NICs / Multiple Default Gateways

    Posted May 19, 2023 01:36 PM

    Hi,

    thank you for your quick answer, really appreciated.

    This is something more similar to a workaround, that is good, but not enough for us as a final solution. 

    We are trying to contract the VMware support in order to have an official solution, if i will have it , i will update you on this thread.

    thank you again

    Ivan