Frequently Asked Questions: Troubleshooting

Why can't I log in with passwordless ssh?

There are a number of reasons why your passwordless ssh setup might not be working but by far the most common (and the hardest to detect on the client side!) is incorrect permissions on your .ssh directory. Because the authorized_keys file contains sensitive information it must not be readable by any other user. Therefore you should ensure that the file $HOME/.ssh/authorized_keys have permissions -rw------- (i.e. 600). 660 (-rw-rw----) will not work even if you are the only member of the group that owns the authorized_keys file. The same caution about permissions applies to the .ssh directory itself.

Why does emacs complain when I try to edit an XHTML file?

We recently (summer 2003) installed a very whizzy editing mode for emacs called psgml. Unfortunately it's actually an SGML mode while XHTML is XML. (Up until version 4, HTML is a derivative of SGML, while XHTML represents a move to using XML, a similar but incompatible type of markup.) You can get rid of the errors by putting emacs into XML mode (M-x xml-mode) but this loses you the nice tag highlighting and can cause problems if you are editing a mixture of HTML and XHTML files. To revert to emacs's default HTML mode, place the following in your .emacs file:

(autoload 'html-mode "sgml-mode" "HTML mode." t)