Last Modified: Aug 19, 2026
Affected Product(s):
BIG-IP GTM
Known Affected Versions:
11.5.1, 11.5.1 hf1, 11.5.1 hf2, 11.5.1 hf3, 11.5.1 hf4, 11.5.1 hf5, 11.5.1 hf6, 11.5.1 hf7, 11.5.1 hf8, 11.5.1 hf9, 11.5.1 hf10, 11.5.1 hf11, 11.5.2, 11.5.2 hf1, 11.5.3, 11.5.3 hf1, 11.5.3 hf2, 11.5.4, 11.5.4 hf1, 11.5.4 hf2, 11.5.4 hf3, 11.5.4 hf4, 11.5.5, 11.5.6, 11.5.7, 11.5.8, 11.5.9, 11.5.10, 11.6.0, 11.6.0 hf1, 11.6.0 hf2, 11.6.0 hf3, 11.6.0 hf4, 11.6.0 hf5, 11.6.0 hf6, 11.6.0 hf7, 11.6.0 hf8, 12.0.0, 12.0.0 hf1, 12.0.0 hf2, 12.0.0 hf3, 12.0.0 hf4
Fixed In:
12.1.0, 11.6.1
Opened: Oct 16, 2015 Severity: 3-Major Related Article:
K22407421
A configuration with a DNS Express Zone with an underscore in the name does not load, even though the gtm global-settings general domain-name-check is set to any of allow-underscore, svn-compatible, or none.
Cannot load the LTM configuration when restarting BIG-IP system when DNS Express Zones that have an underscore character in the name.
-- Configuration setting gtm global-settings general domain-name-check is set to any of allow-underscore, svn-compatible, or none. -- DNS Express Zone exists with an underscore in the name.
Force the GTM configuration to load by sequentially running the following commands: tmsh load sys config gtm-only. tmsh load sys config.
All FQDNs may now contain underscore character. The BIG-IP system now correctly load configurations that contain DNS Express Zones with underscores in the name.