I cannot get Mac Mail to trust permanently a self-signed IMAP certificate; but if you can generate the certificate with your own authority, get the authority's public certificate ("pem") file, and do the following:
- Start the Keychain Access utility, select "Add Keychain…" from the File menu, and choose /System/Library/Keychains/X509Anchors.
- Press the "Show Keychains" icon near the upper right-hand corner of the window, and select X509Anchors from the list.
- Now select "Import…" from the File menu and choose the certificate file; in the attributes pane near the bottom of the window, next to "When using this certificate", select "Always trust" from the pop-up menu.
By the way, here's the required certificate file for the Caltech Alice mailserver.
© M. Vallisneri 2012 — last modified on 2010/01/29
Tantum in modicis, quantum in maximis