Our v400s can do LDAPS for mail recipient verification just fine, but so far as we can tell can't do LDAPS for SMTP AUTH (aka, "Relay Using Authentication") sender authorization. Perplexing - why do one differently than the other?
Opened a case with tech support, no solution thus far. Tier 1 misunderstood the nature of the problem and has wasted some time, trying to get them back on the right track... I think we have, but I thought I'd post here to see who else might be in this boat.
It's our understanding based on Microsoft Security Advisory (ADV190023) that in March 2020, "plain" LDAP over port 389 will stop working. Only secure LDAP will work.
All indications are, in March our SMTP AUTH (authenticated relay) will cease to function. I'm 100% sure there are many other Barracuda customers facing this issue, yet it appears Barracuda is unaware of the March 2020 deadline to fix this... or their systems BREAK. Unless, of course, there's a solution I am not privy to... and nor is tier 1 support.