ADC

Jumbo frames support for DNS to handle responses of large sizes

January 2, 2023

Contributed by:

C S

Starting with Citrix ADC 12.1 build 49.xx, DNS supports jumbo frames for handling UDP responses greater than 1,280 bytes. Previously, the Citrix ADC appliance only supported UDP packet size only up to 1,280 bytes.

You can set the maximum UDP packet size that the appliance can handle in proxy, ADNS, and forwarder modes by configuring the Maximum UDP Packet Size parameter value. For example, if the Maximum UDP Packet Size parameter value is set to 4096, the appliance can handle DNS response of size 4,096 bytes.

Important

In proxy mode, the least size between the client request OPT payload size and the Maximum UDP Packet Size value is considered for sending DNS queries to the back end. For example, if the client request OPT payload size is 3000, and the Maximum UDP Packet Size value is 4096, 3,000 bytes DNS queries are sent to the back end.

Also, from the back end, the appliance can receive responses of large sizes and process responses of large sizes.

In forwarder mode, the appliance sets the OPT payload size equal to the UDP packet size parameter value.

If the DNS records are local to the appliance, then the appliance can compose response sizes as large as the Maximum UDP Packet Size parameter value. This setting is applicable for ADNS, proxy, and recursive resolvers.

To configure the maximum UDP packet size using the CLI

At the command prompt, type:

set dns parameter [-maxUDPPacketSize <positive_integer>]
<!--NeedCopy-->

Example:

set dns parameter -maxUDPPacketSize 10000
<!--NeedCopy-->

Note:

The minimum and maximum value that you can set for the Maximum UDP Packet Size parameter is 512 and 16384 respectively. Default value is 1280.

To configure the maximum UDP packet size using the GUI

Navigate to Traffic Management > DNS.
In the details pane, click Change DNS settings.
In Maximum UDP Packet Size, specify the maximum UDP packet size.
Click OK.

The official version of this content is in English. Some of the Cloud Software Group documentation content is machine translated for your convenience only. Cloud Software Group has no control over machine-translated content, which may contain errors, inaccuracies or unsuitable language. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, suitability, or correctness of any translations made from the English original into any other language, or that your Cloud Software Group product or service conforms to any machine translated content, and any warranty provided under the applicable end user license agreement or terms of service, or any other agreement with Cloud Software Group, that the product or service conforms with any documentation shall not apply to the extent that such documentation has been machine translated. Cloud Software Group will not be held responsible for any damage or issues that may arise from using machine-translated content.

Jumbo frames support for DNS to handle responses of large sizes

January 2, 2023

Contributed by:

C S

January 2, 2023

Contributed by:

C S

Jumbo frames support for DNS to handle responses of large sizes

To configure the maximum UDP packet size using the CLI

To configure the maximum UDP packet size using the GUI

In this article