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What’s Really Involved in Picking and Changing ISPs September 30, 2006

Posted by selkowitz in Networking.

Hardly any business can survive without internet access, yet as critical as it is most businesses underestimate the complexity of choosing or switching internet service providers (ISPs).

What makes this oftentimes more complex is the companies selling internet service (phone companies and cable TV companies) usually don’t have salespeople that understand computer networks.

Here’s a few issues in picking a provider:

An SLA or service line agreement is a promise the ISP makes regarding uptime, performance, and repair times. Not all services have SLAs and your company may not need it – but its a consideration. Any service without an SLA is “best effort” and their definition of “best” and “effort” may not be yours.

Support varies incredibly, some companies a large, well trained staff available 24/7 and others will get back to you in a few hours or days. I’ve even had the case where the one guy who could handle hosting issues was out for a week, so email couldn’t get setup! Ask some serious questions here and even call the support line to see if you get a menu, human, or voicemail.

Not all networks are built the same – some have better equipment, better backbones, lower utilization, etc. Even who’s on their network can matter – for example if your business service runs on the same network as residential service you may see slowdowns in the afternoons as kids get home from school.

Issues like dynamic or static IPs, bridged or routed mode, etc are very important and not all providers support all options (or charge excessively for them).

Speed is the issue most advertised, but while its an issue, its often misrepresented. For example yes, Cable has a much faster theoretical download speed than a T1, but no guarantees. Plus a T1 delivers significantly greater upload speeds which is important for VPNs, mail servers, and any business sending out files. Not to mention the latency issues when running VPNs or RDC.

Once you pick a service and provider, you may need to change quite a bit – and chances are your new ISP won’t help.

If you use static IPs, you’ll need to have someone on hand to reconfigure the firewall.

If you’re switching your web hosting to the new ISP, you’ll need to migrate hosting and change DNS settings with your registrar.

MX Records
If you run a mailserver, you’ll need to change your MX records with the webhost to continue to receive mail. Ideally you have both the old and new MX IPs in the DNS during the change to make the change smoother.

Reverse DNS
If you run a mailserver, you’ll also want to request a reverse DNS entry from the ISP to help your mail be properly identified as legit instead of spam.

External Access
If you access the network externally by IP instead of domain name, you’ll need to change all those settings to once again connect. This most likely will affect VPN users.

Its not to say the companies selling internet service are bad for not helping – this is highly complex stuff which varies by each network, making it best left to your own IT staff or consultants. Obviously since we sell phone and internet service we provide this service to our clients often at no charge, but we’re rare in doing this.



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