Enabling DKIM signing for your domains on Barracuda Email Security Service can help you keep your email content intact and untampered with throughout the delivery process. This helps preserve your identity and eradicate spam and phishing attacks.
Currently, Barracuda doesn't support DKIM signing for your outbound emails. If you want to authenticate your domains using DKIM you need to configure the protocol on your mail server.
Note: In case you set up DKIM manually on your mail server, please ensure Barracuda is not adding a footer to your outbound messages as that may result in unwanted DKIM failures for your emails.