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Centralized Bookmarks

As you might already have noticed, the Wiki's toolbox portlet on the left has a link called ” Alien's bookmarks”. This links actually transfers you to my private installation of a SiteBar bookmark server. Now you ask, ”what is a bookmark server, and why would I use it?”. Good question, with a proper answer.

Just think about it - how many times have you sat behind a computer, thinking about that one bookmark you saved on another computer, and now you're not able to remember the site link that the bookmark pointed to. I don't know about you, but I use many computers, and sometimes multiple Operating Systems per computer. This is screaming disaster when you want to keep track of all these interesting sites you've found and bookmarked! Your bookmarks will invariably end up on the wrong computer.
Enter the bookmark server.

In the early days of Mozilla, when it still called itself Netscape :-) you could configure your browser to store your bookmarks, history, personal certificates and whatnot on a server somewhere on your network. This was a cool feature and I have used it extensively, but it was ripped out when Netscape donated the browser source code to the community and saw itself re-born as Mozilla. On the internet, many a web site popped up to fill the gap, offering a means of centrally storing your bookmarks. None of those really appealed to me, until I came across Sitebar. The SiteBar is one cool application, written in PHP with a MySQL backend, that knows a lot (really a lot) of ways to integrate with your browser, be it Netscape, Mozilla and cousins, Firefox, MS Internet Explorer or Opera. I have not stopped using it and I must say, I cannot do without it any more! Easy access to your bookmarks at all times is just like using DSL or Cable Internet - once you have it, you can't imagine working at your computer without it.
Read the instructions at the Sitebar web site and decide whether you want to take a free account on one of the public servers, or pay for extra features, or run a Sitebar server on your own computer (as I do, the software has a GPL license). I was so happy with it, that I contributed back by finishing (and then keeping uptodate) the dutch translation of the user interface.

Since the Sitebar uses Access Control Lists (ACL), I could quite easily share part of my bookmarks with the world (read-only) whilst keeing a lot of my other bookmarks to myself. Sharing bookmarks between groups of users is possible too, in fact this is an exciting feature.

Sitebar in the office

This is a story I wrote about using Sitebar in a corporate environment. I submitted this to the SiteBar authors upon their request, and I guess it will appear on their web site sometime.


SiteBar is a network bookmark server with some obvious advantages - you can get rid of all the local bookmarks files on computers you use for work & play. This is explained and documented in full detail on the sitebar.org website.
What I want to document here, is how we use SiteBar in combination with a global LDAP Directory and Linux Terminal Server clients. I work for an world-wide organization that uses OpenLDAP to store network user accounts on a global level. We are starting to use these LDAP accounts for more and more network services - we're going towards a web-based infrastructure and several of the applications still have to be adapted for LDAP authentication. Our goal is that users will need just one account and associated password for all the network services in our global LAN.

One of the network services we provide in our international headquarters is LTSP (the Linux Terminal Server Project). We have setup a LTSP server and several diskless clients, so that visitors from other offices can work behind a computer if they need to.
Originally we used LDAP accounts to let people login to the diskless clients (and this is still being used in the ICT Department) but for our “internet cafe” we did not even want to expose our visitors to a logon screen. We solved that by letting the diskless workstations auto-login as a “guest” user when they boot up. The KDM display manager has an auto-login feature built-in, so that's what we use. When someone logs out of the machine, the “guest” profile is reset to it's default state, so that the next visitor does not suffer from a polluted desktop environment.
By the way, although we use KDM for logging in, we run the XFCE window manager because in our opinion, KDE is too heavy for the thin clients.

This auto-login configuration resulted in a problem for the users of these LTSP clients, because the XFCE desktop environment does not save any of the changes that visitors make to the “guest” profile.
The most needed feature was that of easy access to people's bookmarks. We installed a SiteBar server in our network, added the LDAP Authentication plugin, and configured this to use our global LDAP Directory. We modified the “Public Bookmarks” so that these contain useful links to for instance our self-help Intranet pages and the main Intranet services. Even people without a login account are able to use this centralized bookmark list, which we are now able to change if needed, from any workstation we, the Administrators, happen to work at.

This setup turned out to work amazingly well - anyone with a LDAP account and being member of a specific LDAP “group” is able to use our SiteBar server without any further action from the Administrator. The LDAP Authentication plugin uses a LDAP “search filter” expression which you can tune to your heart's desire. Our setup looks like this:

LDAP Server:             ldap.global.lan
LDAP Protocol Version 3  "checked"
LDAP Mail Filter         (&(mail=%s)(objectClass=SiteBarPerson))
LDAP User Tree           ou=staff,dc=global,dc=lan

The “login name” that people enter at the SiteBar server actually is people's email account (as stored in the LDAP “mail” attribute) and their password is the LDAP account's password (as stored in the “userPassword” attribute).
We extended our OpenLDAP server's schema with an ObjectClass called “SiteBarPerson” which is derived from the LDAP ObjectClass “Person”, purely so that we can use it for filtering while we are in Pilot. We will probably remove that restriction once we go into production.
By the way, the default search filter for the LDAP Authentication plugin is:

"(&(mail=%s)(objectClass=posixAccount))"

which means that anyone with a UNIX login account can use the SiteBar server with the LDAP plugin in it's default configuration.

Now that we have this SiteBar server, it is of course not limited to being used for the diskless clients. In fact, everybody in our organization is automatically able to use it when we make it a public service.
What we did not yet do, but intend to do some time in the future, is investigate if we can setup a replicated MySQL server as the backend to the SiteBar and use a round-robin DNS mechanism so that we can add redundance and speed to our SiteBar server. At the moment, some of our offices are connecting over relatively slow DSL lines and having a replicated SiteBar server available locally (just like we already do for our LDAP Directory infrastructure) would be ideal.


Eric Hameleers, 27-feb-2006


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