Bug ID 750213: DNS FPGA Hardware-accelerated Cache can improperly respond to DNS queries that contain EDNS OPT Records.

Last Modified: Sep 13, 2023

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

Known Affected Versions:
12.1.3,,,,,,,, 12.1.4,, 13.0.0, 13.0.0 HF1, 13.0.0 HF2, 13.0.0 HF3, 13.0.1, 13.1.0,,,,,,,,, 13.1.1,,,,, 14.0.0,,,,,, 14.0.1,, 14.1.0,,,,,, 14.1.2,,,,

Fixed In:
15.0.0,, 13.1.3, 12.1.5

Opened: Nov 16, 2018

Severity: 2-Critical

Related Article: K25351434


FPGA hardware-accelerated DNS Cache can respond improperly to DNS queries that contain EDNS OPT Records. This improper response can take several forms, ranging from not responding with an OPT record, to a query timeout, to a badvers response.


Hardware-accelerated DNS Cache drops the request. Clients will experience a timeout for that query. This is occurring now because of the changes coming to software from certain DNS software vendors that remove specific workarounds on February 1st, 2019. This is known as DNS Flag Day.


-- Using VIPRION B2250 blades. -- This may occur if a client sends a query with an EDNS OPT record that has an unknown version or other values that the Hardware-accelerated Cache does not understand. These errors only occur when matching the query to a hardware cached response. Note: If the response is not in the hardware cache, then the query should be properly handled.



Fix Information


Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips