The latest EXOS release (220.127.116.11 Patch 1-2) includes Zero Touch Provisioning (ZTP), a new EXOS application to enable ExtremeCloud for supported switches. The application automatically executes when a DHCP packet is received. ZTP immediately disables ‘all_cast” flooding (to avoid loops).
In a network with DHCP, an affected switch (with no configuration) will automatically run ZTP which disables “all_cast” flooding on all ports (typically within 5 minutes of booting). This results in basic switching functionality no longer working (e.g. DHCP, ARP, etc...). Clients will no longer be able to connect to the switch and get an IP address via DHCP, and the switch will appear to no longer be forwarding traffic. If this problem is present, the “disable flooding” command will be seen in the output of show configuration vlan
for all ports:disable flooding all_cast port 1
disable flooding all_cast port 2
disable flooding all_cast port 3
etc… A software upgrade is required to resolve the automatic disabling of flooding. The next EXOS 21.1.1 patch release will include a fix (however, it is not currently available).
- Upgrading a switch with an existing configuration to EXOS 18.104.22.168 Patch 1-2 will not produce this issue.
- This will not be an issue when ExtremeManagement 7.0 is being used to discover and configure devices.
- No traffic is being forwarded through the switch
- Unable to communicate with devices through the switch
- Client unable to obtain IP address via DHCP