sysadminman.net

If you’re looking for a photographer for a wedding or other special occasion and are located near Leicester in the UK then please check out AllTimeImages at www.alltimeimages.co.uk which is owned by a friend of mine.

I love my Blackberry Curve. Had it about 3 months now and really pleased with it.

Yesterday I read on the web about an upgrade to the OS (to version 4.5) that improved a few things, including html e-mail - which it didn’t handle very well.

So I decided to upgrade. Now, whenever you upgrade the firmware on a ‘device’ there’s a chance that things could go horribly wrong, but if you take care, make sure the device has enough power and give things time to work everything’s normally ok.

But, after getting half way through the update process last night it bombed out, leaving me with a dead Curve. The only sign of life was a flashing red light (2 intermittent flashes).

Thankfully the Blackberry designers have designed the Curve so that not everything is wiped when you update the firmware and a quick search of the web turned up these instructions which brought my Blackberry back to life.

So thanks ‘Reed McLay‘ - I wasn’t looking forward to ‘life without Blackberry’!!

The way I look at it, you can never have too many tools for monitoring the prefomance of your servers!

And it’s best to look round before you actually need them too. Run them on your system when things are ‘normal’ - that will make tracking down problems a lot easier when things start to go wrong.

A handy little tools that combines the functionality of vmstat, iostat, netstat, nfsstat is called dstat.

If you’re using CentOS this can be install via rpmforge (click here for details on adding the rpmforge repo) by doing a

then you can just run dstat (or ‘man dstat’ for some options)

Here’s an example of the output you can expect to see -

I saw the first ‘externsion scan’ of my Asterisk box this week. That is, an external server tried to register as an extension, starting at extension 100 all the way up to extension 999. I’m assuming if they had found a valid extension number then this would have been been followed by a brute force password (secret) scan.

This is an interesting article explaining the problem a little more - http://michigantelephone.wordpress.com/2008/11/28/why-didnt-freepbx-developers-implement-important-security-patch/

If you’re running Asterisk (and FreePBX) then the least you need to do is make sure that you’ve got pretty strong passwords for your extensions.

If you’re based in the UK or Europe and looking for a cheap ITSP (VIOP provider) it might be worth looking at CallWithUS as they’ve recently launched a UK based SIP server.

As well as the US based servers sip.callwithus.com, east.callwithus.com and west.callwithus.com you can now use uk.callwithus.com. I now get sub 6ms pings from my Asterisk server in BlueSquare to the CallWithUs server.

I’ve been using CallWithUs for a while now and they provide very competitively priced DIDs and termination rates.

Sysadminman is now offering UK based Virtual Private Servers running Trixbox and Elastix.

Please see here for details - http://sysadminman.net/uk-voip-vps.html

Here is my CallCentric configuration for FreePBX.

If you’re thinking about signing up with CallCentric please use my referral link here. Thanks.

Please note: the above number starting 1777 is your account number and not you DID number

You also need to add 2 lines to one of the configuration files to correctly extract the DID number from incoming calls.

Edit /etc/asterisk/extensions_custom.conf

Add the following lines

Then restart Asterisk

You should now be able to create Inbound Routes based on you CallCentric DID numbers

I’ve been using CallCentric as one of my SIP trunk and DID providers for several months now and it has worked really well. If you use FreePBX (or one of the prebuilt distributions that use it such as Trixbox, Elastix or PBX-in-a-flash) and use this link to sign up for a free CallCentric account I will configure your trunk in FreePBX for free.

Please use the contact form here if you would like to take up this offer.

Some of the services offered by CallCentric are -

• US DID numbers from only $2.95/month
• DID numbers in cities all over the world
• US calls at only $0.0198 per minute
• UK landline calls only $0.0198 per minute
• Unlimited calling or pay-as-you-go plans

I’ve used Sipgate for the past few years with my Asterisk box and have been pretty impressed.

For anyone else looking to use Sipgate with Asterisk/FreePBX here is my trunk setup

If you are using NAT between your Asterisk box and Sipgate you will need “canreinvite=no” and “nat=yes” or you will probably get one way audio only on your calls

Edit: context changed to “from-trunk” to make the post clearer

Sysadminman is now offering UK based Asterisk VPS servers that have Asterisk, FreePBX and A2Billing installed and ready to use. These VPSs are hosted in one of the premier datacentres in the UK (BlueSquare) and have low pings to UK and the rest of Europe.

Asterisk and FreePBX combined make an extremely flexible and easy to manage “virtual telephone system” and A2Billing is a billing application enabling you to charge for calls made using your system if required.

Some possible uses of an Asterisk VPS are -

• Small businesses wanting to manage a collection of SIP extensions
• Reselling calling cards or VOIP termination
• People who do a lot of traveling and want to stay in touch wherever they are
• Route calls based on time of day, DDI, CLID, etc…
• Provide contact telephone numbers in cities around the world all routed to your local phones over the internet
• Voicemail to E-mail

See here for more details and have you have any questions please get in touch

Matt