Changing the cPanel "Configure Email Client" server addresses in WHM 11.34

One of the great things about cPanel is how easy it makes it for non-technical people to use, for instance within Email Accounts, clicking More and then Configure Email Client provides you with links to automatically configure several email clients, or the details required to do it manually. The data is automatically generated to show the relevant domain's POP3/IMAP/SMTP server details (specific to each domain), but what if you prefer to have a single set of service addresses, how do you update this page to show your preferred details.

In the previous version it was quite simple, you simply edited the clientconfinclude.html that's found within /usr/local/cpanel/base/frontend/x3/mail/ and replaced the dynamic code with your static text.

With WHM 11.34 that's changed, and the .html file no longer controls any of the data, instead it calls the template file clientconfinclude.tmpl which then generates all of the content. Simply doing the switch like before isn't as simple any more, especially if you're not much of a coder, but it's still doable with some minor modifications. Unfortunately the code seems to use multiple methods to call the server addresses, so you have to do different mods for different sections of code.

First all we have the SSL hosts, which is easily the simplest part. Line 11 to line 24 deals with getting those details, with the next section storing them for use later. Without deleting anything simply insert these three new lines immediately before line 26 that begins "SET ssl_hosts = {" :

SET imap_ssl_host = 'imap.mydomain.com';

SET pop3_ssl_host = 'pop3.mydomain.com';
SET smtp_ssl_host = 'smtp.mydomain.com';

That will then force all SSL references to use your information. Now look for the line :

SET non_ssl_mail_server = webmail_settings.domain;

Copy it, and edit the entries so you have :

SET non_ssl_mail_server = 'pop3.mydomain.com';

SET non_ssl_mail_server_smtp = 'smtp.mydomain.com';

In the manual settings section, if you'd prefer the default POP3/IMAP to be IMAP then change pop3 to imap above. Now look for the line :

[% locale.maketext("Outgoing Server:") %]

at around line 685. On the next line, change "non_ssl_mail_server" to be "non_ssl_mail_server_smtp" (so it matches the name used in the last step).

If you save this file and reload the page you should now find most of the links / text now points to your preferred addresses. Unfortunately it's not perfect, there are a few entries that display incorrectly, and I haven't yet worked out where they get their information or how to change it, but hopefully it will be a bit of help for someone.

Tracking Linux server load and processes over time

Tracking down the cause for high load on a server can be a challenge, especially when issues are happening when you can't keep an eye on it, but it's a challenge I've been facing recently. While there were no issues with the server's response, I discovered at certain times (often in the evenings) the load average would become high enough to cause Exim to briefly pause processing the mail queue.

After hunting round for a easy way to track the server's state I came across a simple script from Craig Edmonds that did the job. It very simply generates an email containing a variety of status information, including most importantly the process list data from Top, and sends that to you in an email. By scheduling the script to run every minute you get a snapshot of the servers state at regular intervals. Since the subject line includes the load average you can easily look through the messages, spot those times with a high load, and see what the server is doing.

In my case I adjusted the script slightly to include $todaydate in the subject line, since the above issue with Exim meant I couldn't always rely on the message being received in the correct order.

There was one problem I found with this solution. The script runs a single iteration of Top and inserts the output of that into the email, however as you can see from the Man page for Top :

       The  top command calculates Cpu(s) by looking at the change in CPU time
       values between samples. When you first run it, it has no previous  sam-
       ple  to  compare  to, so these initial values are the percentages since
       boot. It means you need at least two loops or you have to  ignore  sum-
       mary output from the first loop.  This is problem for example for batch
       mode. There is a possible workaround if you define the CPULOOP=1  envi-
       ronment variable. The top command will be run one extra hidden loop for
       CPU data before standard output.

each email I received had identical CPU data. While I could tell the server's load was high, I couldn't see what the state of the processor was at that time. I didn't fancy messing around with environment variables, so instead opted for a solution found here, and adjusted the line calling Top as follows :

    $process_list = shell_exec('top -b -n2 | awk "/^top/{i++}i==2"');

So I found a simple and easy way to track what's happening on the server, though of course with an email a minute it's not something I'll be running long term.

I wish I could say that was the end of it, but unfortunately this turned out to be the beginning of my struggle and confusion, brought on in no small part to the number of confused explanations of Load Average operations, but I'll discuss that in my next post.

References :

http://www.craig-edmonds.com/abuse-monitoring-script-for-cpanel/

http://www.unix.com/gentoo/77494-top-batch-mode-cpu-info-wrong.html

Getting started with PowerShell

So what is it about PowerShell that interests me? Well as someone who started out in the server admin world with a hand full of Linux boxes, albeit in a fairly amateur capacity, I've always naturally been comfortable working at a command prompt. In a Windows world though it's always seemed that to automate anything via scripting there are so many ways to do things, depending on what you want to achieve, with none of them really covering all the bases. Traditional batchscripts, vbscript, wmi, adsi, no one scripting technology really covers everything, and you end up using a collection of things, with one method calling another method etc, since each method lends itself so well to some things more than others.

For instance, I in one script I wrote, you've got a batchscript handling the basic flow and logic of the script, that then calls a few of the GNU ported linux functions like grep, tail, wget etc, and uses vbscript to handle sending e-mail using the JMail component, and at one point calling WMI functions as well!

When I first heard about PowerShell it sounded like finally there might be a language I could invest some time into learning, safe in the knowledge that it could cover what ever I was trying to achieve. Of course like many things there was the question, 'is this too good to be true?', and at first it was. After all, it's great that you can control Windows 2008, Exchange 2007 and SQL Server 2008 etc via PowerShell, but when you're still predominantly using 2003, 2003 and 2005, that's not a lot of use. Now of course things have changed, and it's worth taking the time to learn the language, so that's what I'm determined to do. I think my first challenge will be to get my head about the basics of the language itself, and how the flow control etc is supposed to work, and then work on re-writing many of my more commonly used scripts to use PowerShell instead.

I'll keep you posted on how I get on.