Last Modified: Jul 18, 2026
Affected Product(s):
BIG-IP AFM, GTM, LTM
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
Fixed In:
11.6.0
Opened: Feb 25, 2014 Severity: 3-Major Related Article:
K16240
IANA recently assigned option code 0x0008 to the client-subnet option of the EDNS0 record. Previously, the value was undefined, but processed as 0x50fa by various vendors.
The BIG-IP software treats the newly assigned value, 0x0008, as malformed, and the query is dropped.
EDNS0 with new client-subnet option code.
None
Option code 0x0008 to the client-subnet of the EDNS0 record is now recognized, so the BIG-IP software now accepts both 0x50fa and 0x0008.