For more information regarding the security incident at F5, the actions we are taking to address it, and our ongoing efforts to protect our customers, click here.

Forum Discussion

CWaldon's avatar
CWaldon
Icon for Nimbostratus rankNimbostratus
Jul 08, 2019
Solved

Changing subnet mask of ConfigSync/Failover Address

Hello,

 

I'm in the beginning stages of adding two new devices to an existing BIG-IP LTM cluster. When the initial two devices were configured the ConfigSync/Failover addresses were set up as a point-to-point (/30) subnet on a dedicated VLAN. I'd like to change the subnet mask of these addresses but the IPs will stay the same (e.g. 192.168.100.1/30 will become 192.168.100.1/29) so that there's room in the subnet for new IPs in order to add the two new devices into the cluster but I'm concerned that modifying the mask will cause a failover to trigger. These are production systems so I cannot failover unless I have an appropriate change window but I'm not sure if it's even necessary.

 

Does anyone know if this will cause a failover or flip the active/standby device?

  • Hi CWaldon,

     

    I just tested with a pair of virtual F5s and modifying the subnet of my configsync/failover IPs from 255.255.0.0 to 255.255.255.0 did not cause a fail over or any traffic disruption on that vlan. 

     

    Best,

    Andrew

2 Replies

  • Hi CWaldon,

     

    I just tested with a pair of virtual F5s and modifying the subnet of my configsync/failover IPs from 255.255.0.0 to 255.255.255.0 did not cause a fail over or any traffic disruption on that vlan. 

     

    Best,

    Andrew