Bug ID 483974: Unrecognized EDNS0 option may be considered malformed.

Last Modified: Apr 28, 2025

Affected Product(s):
BIG-IP GTM, LTM(all modules)

Known Affected Versions:
11.5.0, 11.5.1, 11.5.1 HF1, 11.5.1 HF2, 11.5.1 HF3, 11.5.1 HF4, 11.5.1 HF5, 11.6.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3

Fixed In:
12.0.0, 11.6.0 HF4, 11.5.1 HF6

Opened: Oct 10, 2014

Severity: 3-Major

Related Article: K16911

Symptoms

Unrecognized edns0 option may be considered malformed and dropped by the BIG-IP system.

Impact

All queries containing unrecognized option code are dropped. RFC says unrecognized options MUST be ignored.

Conditions

Client sending queries with non-standard edns0 option code. The BIG-IP system is configured with a DNS profile.

Workaround

To work around this issue, write an iRule to parse binary UDP payload; remove option from edns0 record.

Fix Information

Unrecognized DNS EDNS0 options are now ignored.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips