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Archive for the ‘Communications’ category

Know your USB!

July 20th, 2010

A Brief History

Universal Serial Bus (USB) was developed and invented by Ajay Bhatt while working for Intel and is a specification to establish communication between devices and a host controller (usually a PC).  It was is intended to replace the many confusing varieties of serial and parallel ports.

USB can not only connect computer peripherals such as mice, keyboards, digital cameras, printers, personal media players, flash drives, and external hard drives – it can also power them!  For many of those devices USB has become the industry standard connection method.

Although it was originally designed for personal computers, it has become commonplace on other devices such as smartphones, PDAs and video game consoles. As of 2008 about 2 billion USB devices are being sold per year, and approximately 6 billion total sold to date!!!

Standard connectors?  Not always…

Despite its original simplicity many companies have adapted their own proprietary connectors, so not all your devices will use the standard formats.  Therefore we recommend you keep your original cables in a safe place.  Here are some images showing the standard connections:

USB Connectors

Supported Operating Systems

Windows 98 was the first OS to support USB connections right out of the box. Since then, virtually every OS on the market is USB enabled. Support for Windows 95 has since been added and third party solutions have been created for support in NT 4.0.

Data Transfer Rates

  • Low or Normal Speed        1.5Mbps
  • Full Speed                           12Mbps
  • High Speed                          480Mbps (USB 2.0)
  • Super Speed                        4800Mbps (USB 3.0)

Note: Not all USB 2.0 devices are certified for High Speed transfer rates. Look for the USB High Speed Logo to ensure maximum capacity.

Did you know…?

Up to 127 devices can be added and controlled by a single USB port and your devices can be up to 30 meters away from the controlling computer system!!!

Required firewall ports to open for Small Business Server 2003 & 2008

May 17th, 2010

Installing Microsoft Windows Small Business Server 2003 or 2008, want to know which ports to open on your router…..

Well here you go!

Small Business Server 2003

  • Post 25 – SMTP
  • Port 80 – HTTP
  • Port 443 – HTTPS
  • Port 444 – CompanyWeb,
  • Port 4125 – Remote Web Workplace, Remote desktop from RWW
  • Port 1723 – VPN

Small Business Server 2008

  • Port 25 – SMTP
  • Port 80 – HTTP
  • Port 443 – HTTPS
  • Port 987 – CompanyWeb
  • Port 1723 – VPN

What is Backscatter? Can I stop it?

May 12th, 2010

So, you log into your email Monday morning and there’s 500+ Non-Delivery Reports for emails you haven’t sent. What’s going on. Has your account been hacked? Unlikely. The more likely reason is that you’re a victim of Backscatter.

What is it? In brief, backscatter is the influx of Non Delivery Reports (or NDR’s) into a victim’s Mail Server (or MTA).

What is an NDR?

Mail Transfer Agents support a service called Delivery Status Notification (DSN) which allows end users to be notified of  the status of an email, such as the successful or failed delivery of email messages.

A non-delivery report is a status message sent by the recipient or interim email server that informs the sender of a email message delivery failure. There are several issues that can trigger an NDR, the most common are when the recipient of the message does not exist or when the destination mailbox is full.

Smarter Spamming?

Email servers offer a simple measure against SPAM by only accepting emails that have a valid source domain.

i.e. The domain exists.

Spammers are aware of this and have a simple way of bypassing this check which is to mimic email addresses from a valid domain.

Spammers use several methods for harvesting email addresses from the web. One method is the use of “Web Spiders”. Spiders crawl the Internet and web sites for email addresses that can be added to a database to be both a recipient, and used as a valid email address for sending spam.

From SPAM to Backscatter

So now you’re in the database, you’re likely to be targeted for the receipt of SPAM, and unfortunately it’s likely that a Spammer is going to use your email address at some point to send a batch of SPAM emails.

Even though you’re not the true source of the emails, you are the legitimate owner of the “Senders” address. As such any Non-Delivery Report is going to be returned to you.

So depending on the frequency of abuse, or indeed the size of the attack, you could potentially about to receive thousands of Non-Delivery Reports thanks to a spammer.

Can it be stopped?

Unfortunately it is easy to mimic someones email address, however there are measures to firstly prevent you being the source of such a violation, and secondly reduce or prevent the influx of backscatter.

The “Sender Policy Framework” or SPF have introduced additional DNS Records (SPF Records) that allow you to specify who is allowed to send email from your domain (Mail Servers). This way, if an email is received by a mail server from a source other than defined in your SPF record, the connection will be dropped and the email will not be processed.

Note: Googlemail, Hotmail and Microsoft are already implementing policies whereby if an SPF record does not exist, your email may be rejected.

Other options include disabling all catchall or wild-card mailboxes. When this feature is disabled the spammer has to match your exact email address and not your domain, so your mail server will not be accepting non-delivery reports for email addresses which do not exist on your mail server.

It is also recommended that you configure your mail server to reject during SMTP transmission rather than bounce email messages which cannot be delivered. Email servers such as Microsoft Exchange, Postfix, Sendmail and Qmail have patches to improve the behavior to create less backscatter.

A better solution

Using an external host to relay and filter your inbound email can prevent the receipt of SPAM and Backscatter, as well as reduce the loads generated by SPAM on your local mail servers.

Be low are a few more resources to give a little more information on the subject.

The Backlash!

The source of a Backscatter attack is no the SPAMMER, but it is the servers that are not configured to reject emails for invalid email addresses. These servers, although they’re the victim of an actual SPAM attack are now being listed on a UCE Blacklist (http://www.backscatterer.org/), which in turn gets your outbound email rejected due to your server being listed on a Black List.

As you can see, it is important to configure your email and DNS services correctly to ensure your neither the subject of a backscatter storm, nor listed unknowingly in a Blacklist.

Other Resources

Open SPF – http://www.openspf.org/
SPF Record Creator – http://old.openspf.org/wizard.html
Microsoft Sender ID Framework - http://www.microsoft.com/mscorp/safety/content/technologies/senderid/wizard/
Reducing Backscatter on Exchange – http://www.avianwaves.com/Blog/default.aspx?id=31

Small Businesses and Voice over IP Telephony

April 19th, 2010

For Small to Medium Enterprises (SME’s). VoIP offers many ways to enhance and extend your businesses internal and external communications as well as offering valuable business benefits.

With the limited expertise available in the marketplace and previous restrictions and quality, VoIP is still a “Taboo” subject for SME’s, but this doesn’t need to be the case. The early VoIP standards and services had limitations such as poor audio quality and the limitation of only allowing PC-to-PC calling. These issues are now a thing of the past.

So, what is Voice over IP?

Basically, its your digital telephone call transmitted as data across the Internet. As calls can be made over a fixed cost broadband service, VoIP can dramatically lower your telecommunications costs while increasing your productivity and functionality.

Voice over IP in the internal company PBX (telephone system) environment is growing in popularity with all major manufacturers work running internal VoIP for communication between handsets and the PBX. This has been enhancing internal communications with some great new features.

  • Hot Desking - In call centres or hot desk orientated businesses, users can simply “Log In” to a phone to allow their extension to be as mobile as they are, which allows users to freely move from desk to desk.
  • Intra-Office Communications – For the SME with multiple sites, VoIP allows free calls between the offices are data passes over the Internet or preferably via a secure point-to-point connection or an encrypted VPN.
  • Remote Users – There’s no limit to distance as long as you have a broadband connection available you can receive business calls on your laptop enabling users to work from home or roaming users to be accessible on the move.
  • Voicemail to Email – Having your voicemail in your inbox allows you to check your mail in a number of ways without having to either call the office, or be in the office. If for example your smart-phone retrieves your emails, you can listen to your work voicemail on your mobile.

So what else can it offer the business?

Traditionally, VoIP only worked VoIP to VoIP, which was a major limitation. Now, VoIP Providers connect VoIP, the the standard Public Switched Telephone Network (PSTN) allowing communication to standard land line telephone services. Making calls in this fashion saves money on traditional Line Rental call costs as well as other features listed here.

  • Lower Call Charges – “Least Cost Routing” and international calls over IP resulting in much lower call costs. VoIP Providers offer less than 1p per minute 24/7 in the UK with bundled services including UK, International and Mobile calls.
  • Localised NumbersVoIP allows you to offer local numbers. i.e. Your office is based in Leeds, but you want a presence in London? Get a London Telephone number routed to you over VoIP
  • Disaster Recovery - In the event that your office location is unavailable for any reason, simply reroute your calls to another location, instantly. This can also be configured as a backup.

I must recommend from experience that VoIP be deployed over redundant broadband services, or a service with a Service Level Agreement (SLA), just to ensure the service availability. Backup DSL products are relitavely cheap and should always be a business consideration in the current Internet demanding business environment.

So how can VoIP be deployed?

Well, companies with existing traditional PBX phone systems have the choice of an upgrade to allow access to all the features or alternatively, a partial VoIP system can be installed alongside the existing system to mix the new features, with the existing systems, reducing the required investment.

Small Start-Ups can use “Hosted” system, which then requires the purchase of some VoIP handsets and the monthly service costs. This hosted solution allows the extensions to “Log In” from any Internet location allowing you to work from different locations, but still get all the benefits of VoIP and a phone system.

Finally, there’s a full deployment. Using leading brands such as Cisco, Avaya or Samsung etc. you can deploy a new internal system that provides you with all the features available.

So no matter the size of your business, VoIP is a surprisingly flexible, affordable technology that offers enterprise class services at a fraction of the cost.

Businesses rely too heavily on ADSL Broadband…

April 13th, 2010

Most businesses rely heavily on their internet connection. Maintaining constant access to Email and Internet is paramount to daily operation these days and without them we all feel a bit switched off. But most companies don’t realise that broadband is not a guaranteed service!

Ancar B can react quickly to end-user equipment problems but more often than not the issue lies outside of our control on the BT network. At this point we are usually in the hands of a team of Open Reach engineers who are not governed by a Service Level Agreement (SLA) whatsoever. You could be down for ages and there is nothing you can do about it.

If you are unlucky enough to get a problem then you can find yourself in a Business Critical situation very quickly!

If your business relies on the Internet then you should consider a connection that comes with an SLA such as a Leased Line or Ethernet based product, but these can come with large associated costs. If you need a cheaper option then talk to us about our backup ADSL offerings. We can provide multiple ADSL connections carried over separate networks for extra resilience, automatic and manual failover options, store & forward email SMTP feeds and more…

Unfortunately most of our backup ADSL systems are ordered off the back of a major ADSL outage. If you are reading this and rely on your connection then think about getting yourself some cover before you get the problem…?