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Mozzie's avatar
Mozzie
Icon for Nimbostratus rankNimbostratus
Jul 16, 2025

Issue with 2 parallel F5 clusters

Hello everybody and first of all thank you for taking the time to read my issue!   The issue that I have is in regards to a migration We have a productive F5 BigIP cluster (Active/Standby), let's ...
bigip
LTM
migration
Networking
rseries
VGF5's avatar
VGF5
Icon for Cumulonimbus rankCumulonimbus
Jul 16, 2025

Hi Mozzie​ 

 

As per my understanding, you're running into ARP/IP conflicts., what’s happening is that the new F5 is responding to ARP requests for production IPs. As a result, the network is mistakenly sending live traffic to it, even though your virtual servers (VSs) might still be disabled.

Don’t assign production IPs to the new F5 until you're ready to go live. If you need to preconfigure them, make sure ARP is disabled on those IPs to avoid interference. Always ensure only one F5 cluster at a time has those IPs active, having both can lead to traffic blackholing and outages