All of our web servers support PHP 4. All you need to to ensure that your scripts are properly processed by the PHP engine is to name then with a .php suffix (eg. index.php).

PHP File Upload
We have discovered a bug in PHP's upload function on our non subscription web server. This bug effectively prevents PHP programs from completing file uploads. Due to the large number of people who have sought to use this mechanism to circumvent our terms and conditions of service we wont be fixing this bug for some time.

It is still possible to use perl to accomplish this.

Session handlin in PHP
Some of our users have reported difficulties using Session handling in PHP. After investigation we've discovered that this is due to sessions not always being automatically written to the system when a script terminates.

You can resolve this by always explicitely closing sessions using session_write_close();

Perl

The perl interpreter on our web server is located at /usr/bin/perl.

In order to help you produce "good" perl scripts here are some manual pages on the most common aspects of writing CGI scripts in perl:

Before you read these documents there are two very basic points in writing good perl scripts that you should take into account.

1. Every perl script you write should use the "-w" flag on the "shebang" line (the first line in your script which details where the perl interpreter is) like so:

#!/usr/bin/perl -w

This will ensure that warnings are generated when your code is doing something either that is inconsistent or just plain wrong.

2. The second basic piece of crucial advise is that you must turn on the "strict" pragma in perl like so at the top of your script:

use strict;

This will prevent your script from using unsafe constructs and thus prevent almost all of the most common errors in your scripts.

CGI Scripting
The DBI database interface
Mysql specifics when using DBI
PostgreSQL specifics when using DBI
Simpler interface to PostgreSQL - not as complete as DBD::Pg
Sending email from your scripts

The mail transfer agent on our web server is /usr/sbin/sendmail.

All script files need to have 'executable' permission. You can set this for files in your area using a 'good' ftp client.

So long as your perl scripts are in files with a .cgi or .pl extension they should work without any problem.

If any errors occur with PHP or Perl scripts you can now access the error log via the web by adding the line :-
Errordocument 500 http://www.uklinux.net/errors/err500.php3
to your .htaccess file (described below).
You will be asked for your password on a secure web page and then the page will display the contents of the server error log relating to your web pages

If you want to use a cgi-bin please ensure it is called cgi-bin and is located in the root directory of your web space.

The file that executes automatically within any subdirectory of your website may be called index.htm, index.html, index.php3, index.cgi or index.pl depending on the script language used.

Securing your web space
You can require that visitors to your site authenticate themselves before they can access sensitive parts of the site. To do this you need to create and upload a file configuring the site's security settings. This file must be called `.htaccess' and normally looks like this:

AuthName "My access authfile"
AuthType Basic
AuthUserFile /www/username.uklinux.net/.htusers

require valid-user

In the meantime this is an online utility for generating username:password pairs for pasting into an .htusers file. (One per line). We make no guarantees regarding the security or otherwise of this external utility and use of it is at your own risk :)

Note that you should only use a file called .htusers to hold user/password information for your web site authentication. This is because in order to protect your authentication files from prying eyes we have set up the system such that these files cannot be retrieved by http or ftp.

One side effect of this is that once you have uploaded the .htaccess and .htusers file you will not be able to download them. You will be able to overwrite them with updated versions.

If you need to download your .htaccess or .htusers file please email support@uklinux.net for assistance.

WAP Enabling your web site

UKLINUX offers all users the ability to host a WAP site using their UKLINUX NET web space through our standard Apache web server.

We have already configured the Apache web server to handle standard WAP data types such as .wml, .wbmp, .wmlc, .wmls and .wmlsc.

In addition to this we recommend you create a .htaccess file for the directories in your web space from which you serve WAP data with the following options set:

Header set Pragma no-cache
Header set Cache-Control no-cache,must-revalidate

For any CGI:
SetHandler perl-script
PerlSendHeader Off
PerlHandler Apache::Registry

Please note that we do not offer any support in getting your WAP site up and running beyond facilitating the service in this way. It is up to you to learn how to write good wml pages and to convert graphics to wbmp format - you can do this using ImageMagick.

Email Help

Sending Email

When you are dialled into UKLINUX NET you should use our mail server for sending emails. This is because all of the IP addresses that are assigned to dial up connections are listed in the anti-spam dailup lists that are used by many mail servers on the Internet to protect themselves from SPAM/UCE.

To use our mail server when you are dialled in to UKLINUX NET all you need to do is to configure your mail software to use smtp.uklinux.net as the outgoing or SMTP mail server.

An added benefit of this is that because our mail servers are connected to the Internet 24 hours a day, every day, they can keep retrying to send your email to sites that are temporarily unavailable whereas your own system may not be connected to the Internet for long enough to get messages through to such sites otherwise.

If you are a subscription member (ie you pay a subscription for your UKLINUX membership) then you can send email via our servers even when you are not dialled into our UK local rate access numbers.

To do this you will need to configure your mail software to use Authenticated SMTP when talking to our mail server and use your UKLINUX user name and password to authenticate your connection.

We've verified this method with sendmail, postfix and exim MTA's for sending mail via our servers as well as Netscape/Mozilla Messenger, Balsa, Outlook Express and Eudora mail client software.

Please check your mail software documentation to see how to configure your system to use Authenticated SMTP for sending email.

Note that you can only use Authenticated SMTP to send email via our servers if you are paying a subscription for your membership. Others attempting to use the service will receive a "UKLINUX Relaying Denied" message and will not be able to send email.

Some basic details on configuration of common UNIX MTA's for SMTP AUTH are available here

Receiving Email

We offer two ways for your to receive your email.

POP3 Access

Firstly we offer POP3 access. This is what most of our users prefer and is very simple to use. You simply need to configure your POP3 client software to connect to pop3.uklinux.net using the POP3 protocol with your UKLINUX NET username and password.

If you have not upgraded your membership to one of our subscription options you will only be able to access the POP3 service when you are dialled into our UK local rate access numbers.

If you have upgraded to a subscription membership you can access the POP3 service from any Internet connection.

SMTP Mail Push

We also offer a direct SMTP push mail delivery option.

With the SMTP Mail Push service we will configure DNS MX records for your account and any domains you host with us so that email is always delivered directly to your system when you are connected to the Internet and when you are not connected to the Internet all email will be directed to one of our mail servers where it will be queued for delivery the next time your connect to the Internet.

This option is available to all of our users regardless of whether you pay for a subscription membership or not.

Those who have upgraded to a subscription membership and who have a static IP address elsewhere can have the mail system set up to deliver mail to that system. Note that this option is only available to those with a static IP address (ie. one that never changes and is specifically assigned to you).

If you want to use the SMTP Mail Push service you will need to request the feature by emailing support@uklinux.net and asking for it.

Solving problems with your mailbox

Mail being bounced due to quota exceeded

Users who use our service without paying any subscription have a 10MB mailbox quota.

Those who use a subscription account have a 20MB mailbox quota.

In addition to these limits we provide a buffer zone of up to an extra 5MB of disk space that can be used for up to 7 days. If your mailbox exceeds its given quota for a period of more than 7 days or exceeds the quota plus 5MB buffer we will stop accepting email for your account.

To prevent email to your account being bounced you should ensure that you regularly connect to our mail server and download your email and that your mail client software is not configured to leave email on the server after downloading it.

Mailbox blocked with a message you can't download

While we do not provide a predesigned facility to do this we are happy to provide details on how you can directly manipulate your UKLINUX POP3 mailbox.

Note that these instructions are somewhat involved. Unfortunately that is necessary.

In order to remove messages from your POP3 mailbox without having downloaded them you will need to connect to our server using a telnet client and follow the instructions below:

Firstly, using a telnet client, connect to pop3.uklinux.net specifying port 110 for the connection.

If you don't specify port 110 for the connection you will be refused access by our firewalls.

Once you are connected you will see a prompt like this:

Don't worry if the prompt you get is not identical - certainly the last bit will be slightly different.

You will receive no further prompts so you need to be careful to enter the following details properly. Note that below [username] and [password] should be replaced with your UKLINUX username and password. <enter> means press the enter key on your keyboard.

Now you will need to login to the POP3 server. You do this like so:

user [username]<enter>

You should receive the following response:

+OK [username] selected

Now you enter your password like so:

pass [password]<enter>

If you have entered the correct user login and password details (and you are dialled into UKLINUX if you are not a subscription member) you will receive confirmation of your login like so:

+OK Congratulations!

You can now proceed to manipulate your mailbox. To do this you need to know a few simple commands.

The LIST command will give you a simple list of messages in your mailbox and their size. Note that all you get from this command is an index like so:

+OK 2 messages (194556 octets)
1 2117
2 192439
.

To find out what is in any particular message you can use the TOP command to view the beginning (including the full headers) of any message. The TOP command requires two parameters.

The first one is the index number of the message you are interested in and the second is the number of lines you wish to see of the message - note the full header will be displayed regardless of the number of lines you elect to view. It's usually sufficient to only view one or two lines of a message so as to verify it is the message you are interested in.

Once you have identified the messages you want to delete you can do so easily using the DELE command like so DELE n where n is the index number of the message.

Once you are happy that you have "cleansed" your mailbox you can use the QUIT command to exit the session and then use your regular mail agent to download the mail you are interested in.

Using procmail to manage your email

Users who have subscribed to Standard level membership or better, as defined in our current membership details page are able to use procmail to automate much of the management of their email before the messages are downloaded.

This can be a very powerful tool enabling you to forward email that has been sent from or to a particular email address to another email address, a file or even a program (note that our standard T&C prohibit the use of binaries unless specifically authorised).

You can even use this to perform extra anti-spam measures to the basic ones we implement and anti-virus checks on emails you receive so that you never even have to see them.

Procmail can be a little daunting at first as just like any other powerful tool you need to learn how to use it properly to get the most from it. In order to make this easier here are some manual pages for procmail including one full of examples on how to implement common requirements.

Do note that you need to separate each element of your procmail rules with newlines so that each part is on a separate line - ie like this:

	:0:
	* ^TOmyemail
	! another@elsewhere.com

There are links to useful procmail documentation below however before you move onto them we'd like to detail the specifics for one use of procmail:

How to prevent mail loops

In order to prevent such loops you need to add an extra header to messages that you are forwarding elsewhere and check incoming messages for the presence of that header.

To insert such a header you need to include a rule in your procmail configuration like so:

:0 fhw
* !^FROM_DAEMON
* !^X-Loop:
* ^TO@[username].uklinux.net
| formail -i"X-Loop: @[username].uklinux.net"

Do remember to replace [username] with your own username.

You can set different X-Loop headers for different email addresses by simply customising the above rule, changing the "* ^TO" and "X-Loop" sections appropriately.

We recommend that you include the above rule(s) before the rest of your rules so as to ensure that the necessary headers are in place in all forwarded messages. You can, if you prefer, list those rules that only delete incoming email prior to these ones however all the others should be below - especially any rule that forwards email elsewhere.

Of course the above, on its own, is of little use as all it does is add an extra header to emails being processed.

To make use of this you need to add another rule before the rule above to check for the presence of such a header and act accordingly.

As this whole exercise is about prevening email loops the only sensible action to take with messages arriving that already have this header is to delete them - forwarding them would just result in a mail loop, which is what we're trying to avoid.

You could store the message in your UKLINUX account mailbox without forwarding it on, just be careful not to exceed your account quota.

The rule to delete the incoming message that matches the loop condition is:

:0
* ^X-Loop: @[username].uklinux.net
/dev/null

If you want to retain the message in your mailbox use this rule instead:

:0
* ^X-Loop: @[username].uklinux.net
$DEFAULT

You should change the value matched after the X-Loop: string to be what you have set the other rule to create - in our example you'd match on your email address.

This is just one of the things you can do with procmail. For details of how to achieve other things read the documentation below:

Main procmail manual page
The procmail configration file
Examples of common procmail configurations

Please note that your .procmailrc file has to be installed on our mail server and not in your web hosting space.

We do not permit ftp access to the mail server. To upload your procmail recipe file you should use the web interface at https://www.uklinux.net/procmail/

I'm getting an error about mail being refused when I contact your server

If you receive an error message like the following:

550 Mail from x.x.x.x refused by blackhole list [listname]

this means that the system that you are sending email from has a history is being used to send UCE/SPAM and is now blacklisted so we will not accept email from that system.

If you are sending email via your ISPs mail server and this error is coming back then we strongly recommend that you move to an ISP that does not support email abuse.

If you want to be removed from the blackhole lists we recommend that you contact the service that is mentioned in the [listname] section of the message to see what conditions you need to meet to be delisted. At the very least you will need to ensure that your mail systems do not allow unauthorised relaying of messages and that you or your organisation does not engage in sending unsolicited bulk email.

Basic details on setting SMTP AUTH

SMTP AUTH is currently dependant upon the SASL libraries from Cyrus. You need to have these libraries installed onto your system before you can make use of the AUTH extensions to your MTA.

You also need to ensure that the copy of the mail transfer agent running on your system has been linked against the same version of the SASL libraries you have installed on your system at compile time. Recompile it from source if you are not sure - see the documentation for your MTA for help on that.

Note that the instructions below only cover setting up your MTA to act as a client for SMTP AUTH trasmission of email.

SMTP AUTH with Sendmail

A very good guide to setting up SMTP AUTH with Sendmail is available from http://www.sendmail.org/~ca/email/auth.html.

Please do bear in mind however when setting up your system that you are a client in the connection with our servers.

SMTP AUTH with Postfix

Setting up postfix is fairly easy however you will probably need to rebuild postfix to include SASL support (I recommed you also include TLS support) and for this you should ensure you have the latest release of Cyrus-SASL and OpenSSL on your system.

In your main.cf file ensure you have the following settings:

smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/saslpass
smtp_sasl_security_options = noanonymous

You will also need to create the saslpass map file to contain the authentication data to use.

Create the /etc/postfix/saslpass file and edit it to add a line like this:

smtp.uklinux.net	[username]:[password]

[username] should be replaced with your UKLINUX username and [password] with your UKLINUX account password.

Then you need to create the actual lookup file that postfix will use:

postmap saslpass

should do the trick.

SMTP AUTH with Exim
In transport section, add autheticate_hosts line

remote_smtp:
driver = smtp
authenticate_hosts = "smtp.uklinux.net"
end

In Authentication section add - changing username and passwd accordingly:

fixed_login:
driver = "plaintext"
public_name = "LOGIN"
client_send = ": username : passwd"
fixed_plain:
driver = "plaintext"
public_name = "PLAIN"
client_send = "^username^passwd"
end

Help with your account

You can now manage some aspects of your account directly online at https://www.uklinux.net/myaccount. You will need to be either dialled in to uklinux.net or have upgraded your account to access myaccount.

Please note that if you contact us by any means other than your uklinux.net email address we will ask you to confirm your identity prior to making any changes. We'll use the information you gave us when you signed up for the service for this.

Help setting up a database

You can now setup a mysql database using the 'myaccount' section. You will need to be dialled in to uklinux.net or have upgraded your membership and connect to https://www.uklinux.net/myaccount.
For further information look at http://www.uklinux.net/support/mysql.php3
We are still working on scripts to allow creation of postgresql databases. Please bear with us.

Upgrading your Membership

We now offer a range of membership options that include the ability to access email whilst not dialled in to uklinux.net, domain hosting etc. Details are available on the membership page.

Domain Registration and Hosting Services

We offer a full domain registration and hosting service in addition to our regular dialin and membership services.

Our hosting offering includes all the great facilities you expect from UKLINUX so you can build professional sites with perl, php, mysql and postgresql back ends and Server Side Includes.

For details on our domain registration services see our Domain Registration Services page.

If you want to transfer a domain to our servers from elsewhere you will need the following information.

IPSTAG: UKLINUX (for .uk domains only)

DNS Servers
80.84.64.20 - ns0.uklinux.net
80.84.72.20 - ns1.uklinux.net
80.84.64.25 - ns2.uklinux.net
80.84.72.25 - ns3.uklinux.net

Please note that you must inform us that your domain is being transferred to our servers so that we can set up the support services for your domain in time to ensure a seamless transition.

Before you can host a domain with us you will need to have a Silver level or better subscription membership.

There is a £10.00 fee for transfering a domain to or from UKLINUX.NET

Payment Methods We Accept

We are happy to accept payment for member subscriptions, domain registration, hosting options and the various other additional facilities we offer via the following methods:

Credit/Debit Cards^*
Cheque and Postal Order (made payable to uklinux Ltd)

^* We accept the following cards: Visa, Mastercard, Eurocard, Visa Debit, Switch, Solo, Delta and JCB.

Note that cheques and postal orders should be made payable to uklinux Ltd and addressed to:

UKLINUX LTD
Vernon Mill
Mersey Street
Stockport
Cheshire
SK1 2HX

Important Note

We prioritise support requests based upon whether they are sent from a UKLINUX NET email address. Unless your support request is related to a problem dialling in or an email problem it will be treated as a lower priority request.

This is to concentrate the support resources we have and to ensure that those actively using our facilities get support as quickly as possible.

Note that all emails requesting support will be answered. We aim to respond to all support requests within an hour of receiving them (in normal working hours).