Bug ID 744930: IPv6 generic host unable to be probed when only IPv4 server objects are defined

Last Modified: Aug 24, 2021

Bug Tracker

Affected Product:  See more info
BIG-IP DNS, Install/Upgrade(all modules)

Known Affected Versions:
13.1.0, 13.1.0.1, 13.1.0.2, 13.1.0.3, 13.1.0.4, 13.1.0.5, 13.1.0.6, 13.1.0.7, 13.1.0.8, 13.1.1, 13.1.1.2, 13.1.1.3, 13.1.1.4, 13.1.1.5, 13.1.3, 13.1.3.1, 13.1.3.2, 13.1.3.3, 13.1.3.4, 13.1.3.5, 13.1.3.6, 13.1.4, 13.1.4.1, 14.0.0, 14.0.0.1, 14.0.0.2, 14.0.0.3, 14.0.0.4, 14.0.0.5, 14.0.1, 14.0.1.1, 14.1.0, 14.1.0.1, 14.1.0.2, 14.1.0.3, 14.1.0.5, 14.1.0.6, 14.1.2, 14.1.2.1, 14.1.2.2, 14.1.2.3, 14.1.2.4, 14.1.2.5, 14.1.2.6, 14.1.2.7, 14.1.2.8, 14.1.3, 14.1.3.1, 14.1.4, 14.1.4.1, 14.1.4.2, 14.1.4.3, 14.1.4.4, 15.0.0, 15.0.1, 15.0.1.1, 15.0.1.2, 15.0.1.3, 15.0.1.4

Opened: Sep 24, 2018
Severity: 4-Minor

Symptoms

After upgrading to 13.1.0 or later, you may find that IPv6 generic hosts are no longer able to be probed by server objects that have only IPv4 addresses defined. The operation fails with errors in /var/log/gtm: -- notice gtmd[pid of gtmd]: 011ae108:5: Prober Selection: no preferred or fallback probers are available.

Impact

Attempts to probe the IPv6 object fails. Beginning v13.1.0, the system checks whether this GTM has any IPv6 'Device IP addresses' or 'unit IP addresses', i.e., whether the server object has IPv6 IP addresses defined. IPv6 generic host are unable to be probed when only IPv4 server objects are defined. In version 13.1.0 and later, the system can successfully probe an IPv6 generic host only when there are IPv6 IP addresses defined for the server. In versions earlier than 13.1.0, the system can successfully probe an IPv6 generic host even when there are only IPv4 server objects defined, as long as the GTM server has an IPv6 self IP configured. Beginning with v13.1.0, the system now checks to see whether this GTM has any IPv6 'Device IP addresses' or 'unit IP addresses', i.e., whether the server object has IPv6 IP addresses defined. If there are no IPv6 IP addresses, the probe fails. This functionality change in 13.1.0 is a designed to make probing more reliable by checking the addresses configured for the BIG-IP system.

Conditions

This can appear after upgrade from earlier versions to 13.1.0 or later, or in 13.1.0 after adding IPv6 generic hosts, when only IPv4 server objects are defined: For example: gtm datacenter /Common/DC { } gtm server /Common/GTM { datacenter /Common/DC devices { /Common/GTM { addresses { 192.168.1.1 { } } } } monitor /Common/BIG-IP product BIG-IP } gtm server /Common/Generic { datacenter /Common/DC devices { /Common/Generic { addresses { fd12:3456:789a:1::1 { } } } } monitor /Common/gateway_icmp product generic-host virtual-servers { ipv6 { destination fd12:3456:789a:1::1.80 } } }

Workaround

Add an IPv6 address to the server object.

Fix Information

None

Behavior Change