Linux Servers FAQ

• Fedora Core 5
• Fedora Core 4
• Fedora Core 3
• Fedora Core 2
• Fedora Core 2 accessing Windows NTFS
• HTTPS Redirect
• Fetchmail
• OpenOffice.org
• Fedora VPN information
• ECN Explicit Congestion Notification Signalling
• Mime Types & Mozilla
• Unicode files from Windows 2000/XP

Fedora Core 5

If you have enjoyed Fedora Core 4, I can higly recommend upgrading to Fedora 5 and have been using it myself from a week after it's release.

To enable RTSP real audio streaming protocol to use realplay in firefox. Open firefox and about:config then create a "new string" of network.protocol-handler.app.rtsp with value "/usr/bin/realplay".

I have had problems with the 2.6.17 kernels and RAID arrays on Promise FastTrak 20376 as boot devices. But rebuilding initrd for the particular 2.6.17 kernel on your system seems to fix the problem:-

Fedora Core 4

If you have enjoyed Fedora Core 3, I can higly recommend upgrading to Fedora 4 and have been using it myself from a week after it's release.

Fedora Core 3

If you have enjoyed Fedora Core 2, I can higly recommend upgrading to Fedora 3

Fedora Core 2

While Fedora Core 2 is not recommended for production enviroments I can confirm it is proving very reliable and use it for my own dektop. Below is some of the workarounds and extras you may need:-

Fedora Core 2 accessing Windows NTFS

The Fedora Core 2 like other Redhat releases doesn't include support for accessing Windows NTFS partitons as standard. You can add the Open Source NTFS driver support by recompling the kernel with NTFS enabled, or download precomplied versions from below:-
http://linux-ntfs.sourceforge.net/rpm/fedora2.html

Note at present the NTFS linux support only allows read-only access so you may want to also create a Windows FAT32 partition on a dual boot system for the common interchange of files between Windows NT/2000/XP NTFS partitions and Linux. Please see full Linux NTFS detials on:-
http://linux-ntfs.sourceforge.net/info/ntfs.html

HTTPS Redirect

To intercept all requests and redirect them to HTTPS port 443, use the following rewrite script in the Apache httpd.conf:-

What this does is act on any connection which does not come in on port 443. The neat thing is that it then takes everything in the URL after the first slash with the (.*) and remembers it as $1. By "after the first slash" I mean after the slash at the end of http://www.domain.com/ <-- that last slash. So everything after that slash, that is the internal URL, is memorized. The URL is then rewritten as https://www.domain.com/$1 where "www.domain.com" came from the SERVER_NAME httpd variable and $1 is the internal URL as memorized earlier.

Fetchmail

The ideal way of your email server receiving Email is to have a permanent connection to the Internet with SMTP [tcp port 25] open so other Email servers can automatically send you any mail for your domain. Unfortunately in the real world many users only have dial-on-demand ISDN connections to the Internet so SMTP mail retrieval is not a practical option

With linux being used more and more for small email servers and embedded Internet appliances such as the Cobalt Qube3, many users are forced to use POP3 to retrieve email from a global POP account. Fetchmail is the common utility used for this purpose even if hidden by a user interface as in many Internet appliances

Fetchmail is a remote-mail retrieval and forwarding utility intended to be used over dial up TCP/IP links. It supports every remote-mail protocol now in use on the Internet: POP2, POP3, RPOP, APOP, KPOP, all flavours of IMAP, ETRN, and ODMR. Fetchmail retrieves mail from remote mail servers and forwards it via SMTP, to the normal linux SMTP servers agents such as postfix, sendmail, mutt, elm(1) or BSD Mail.

While Fetchmail is a excellent utility it can have one notably problem/feature that needs to be taken into account, when configuring how often Fetchmail polls the remote mail box. Most POP3 accounts don't allow multiple connections yet alot of early linux distributions will automatically start another Fetchmail access if the poll time has expired since the last POP3 access started. If the previous remote mail access hasn't completed yet due to an excess of email waiting at the ISP, and the next Fetchmail access starts this often aborts the previous access. The result is all the email the previous access fetched before being aborted is not deleted from the remote ISP. The next access again fails to fetch all the email within the interval before the next access starts so the same email is read time and time again without removing it from the remote ISP. It is therefore important to consider the speed of your Internet connection and performance of your remote ISP mail server when determining how often to poll the remote mail box. This problem can also occur if your ISP diconnects you due to say a 2 hour limit. See the following example for single channel ISDN:-

Single Channel ISDN and Fetchmail Poll Rate

If you inadvertently end up with a dead lock with mail being continually read multiple times, the answer is to increase the Fetchmail poll interval to something very large, allow all the waiting email to be retrieved in one go without another access starting. Clear the remote mailbox in this way, then reset the poll interval once your sure all the email has been successfully retrieved and removed from the remote ISP mailbox

OpenOffice.org Dictionaries

The latest dsitributions of the excellent OpenOffice.org now comes with a wide selection of different language dictionaries and hyphenation as standard. This can cause problems with excessive ram usage when using spelling suggestion in writer via right-clicking a bad spelling. This can appear as the system hanging for several minutes. To speed things up and reduce the ram usage, edit:-

/usr/lib/ooo-1.1/share/dict/ooo/dictionary.lst

and comment out any languages you don't use.

Fedora VPN Information

2.6 Kernels have IPSec enabled in the kernel. Fedora 2/3 comes with IPSec-Tools providing racoon (IKE deamon) and Setkey. You can also add PPTP and L2TP if necessary:-

ECN Explicit Congestion Notification Signalling

If you are using a 2.4.20 or newer Liunx kernel you may get asked whether you have it enabled or not, as it can have problems with some firewalls and other network servers that don't yet support the protocol. With the present builds of kernels the ECN signalling is disabled. But just incase you have had something accidentally enable ECN, it is controlled by:-

If this file contains a "0" then ECN signalling is disabled. To learn more about the TCP ECN protocol see rfc3540.txt.

Mime Types & Mozilla

Having problems with mime types and Mozilla and trying to get it play multimedia like Real Audio. You need to check out the following three files:-

Unicode text files from Windows 2000/XP

Have you downloaded log files or the like from Windows 2000/XP servers to your linux system only to find they appear unreadable and double spaced with control characters. The file will be in Unicode UTF-16 format where your Linux system is almost certainly wants ISO-8859-1 or UTF-8 character encoding.

You can use "iconv" to convert files between differnet character formats. On our Red Hat system the command syntax is as below, on others check your man pages:-

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Last modified: 21 August 2006

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