Edge MTA's and LDAP
Can Edge MTA servers use Zimbra's LDAP to check if mailboxes exist before relaying them? I have two running sendmail.
I am trying to limit the spammer's dictionary attacks on fake mailboxes. Spamcop is starting to crack down on unsolicited bounces. And do the Zimbra schema's have fields for which servers to relay to? Even non-zimbra servers?
I'm able to query Zimbra's LDAP server with exim. Very easy. Don't know about sendmail. The only glitch you might hit is that by default, the LDAP server is bound to only one IP address on servers with multiple interfaces.
There are no host relay attributes in the schema that I can see, but it's easy to maintain relay hosts manually (again, with exim).