Hugo Haas has been wrestling with Mail.app.

Frustrating for him but interesting for us, he’s found four things that Mail.app can’t do:

• IMAP over SSL does not work if used through an SSH tunnel
• SMTP over SSL does not work if a SOCKS proxy is in use
• When a SOCKS proxy is set, excluding a hostname or domain does not work: it just makes any connection to a matching host fail
• Using an PAC file does not give satisfactory results (I don’t remember the details of this one, but basically I bumped into a number of issues)

I’m not so sure about the last one. Mail seems to negotiate the proxy.pac file at my work without any problems. I’ve never tried to do the other three myself.

Still, it’s nice to know that there is still room for improvement in Mail.app and the hope of even better things to come.mail.app, apple mail, bugs, ssl, ssh, socks

Scalp is a bundle for iCal that enables the sharing of calendars over FTP, SSH or SFTP connections.

The developer created it, he explains, “because .Mac is expensive and WebDAV can be hard to come by”.

It depends on SIMBL (Smart InputManager Bundle Loader), the same Cocoa application hack that powers the Safari plug-in PithHelmet , iAlert and other useful apps. A copy of SIMBL in included in the disk image and must be installed first.

Full instructions on how to install and run the app (some fiddling with URLs is required) are included in the disk image as well. Note especially the known bugs section.

The hack, which only works with iCal 2.0.3, gets its name from “the unfortunate result” of combining cal and scp, the SSH copy command.

Donations from grateful Scalp users are not refused by the developer. You can get Scalp from his web site .ical, ftp, sftp, ssh, calendars, sharing, weddav, .Mac, dotmac, hacks, SIMBL

Tony Perrie at Involution has done something really clever with Mail.app, SSH and port redirection.

But I can’t work out what it is.

Luckily Tony has left a note in the comments which explains it (thanks!):

I wanted to forward my outgoing through my Linux computer that’s hosted at a colocation center outside of work through SSH. So, my Powerbook acts like a sendmail server now, and forwards that traffic that is directly connected to the Internet from behind a firewall.