I see from this following post what one might do to migrate to Zimbra, if one has data in LDAP that includes plaintext passwords:

I'm not so lucky though, my LDAP passwords are in 'crypt' format. If I fire up my LDAP browser, and look at the passwords, they look like one of:

userPassword: {crypt}PR4rUd/wJ9a4
userPassword: {crypt}$1$28HtH18x$S.YXvaGjIBVnZYNEjRA481d

(just because someone is bound to wonder... I copied those password strings in directly, but changed a few characters around :-)

Now, since that's what shows up in my LDAP browser, I figured I could pass them into zmprov:

zmprov SetPassword '{crypt}PR4rUd/wJ9a4'

But no, while it accepts the string, I can't log in with the password I'd expect. Of course, after running SetPassword with a plaintext password, I can log in just fine.

So, any hints on how one might migrate accounts from an LDAP setup where the passwords are not stored in plaintext?