Bug ID 450101: EDNS0 client-subnet support

Last Modified: Oct 06, 2020

Bug Tracker

Affected Product:  See more info
BIG-IP AFM, GTM, LTM(all modules)

Known Affected Versions:
10.2.4, 11.4.1, 11.5.0, 11.5.1, 11.5.1 HF1, 11.5.1 HF10, 11.5.1 HF11, 11.5.1 HF2, 11.5.1 HF3, 11.5.1 HF4

Fixed In:
11.6.0, 11.5.1 HF5

Opened: Feb 25, 2014
Severity: 3-Major
Related AskF5 Article:


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.



Fix Information

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.

Behavior Change