There are many questions to be answered when considering a new ISP: cost, connection speed, download speed at peak times, data transfer limits (and what happens if these are exceeded), contract length, reliability and quality of customer service all spring to mind. It’s usually simple to answer such questions by consulting an ISP’s website, looking up industry or regulator statistics, or by surfing a few review forums. There are other questions, however, the answers to which are more difficult to come by; yet they relate to factors that influence significantly the performance of a connection and its fitness for a particular purpose.

Below are five technical and three ethical questions I think any geek or power user should ask of a prospective ISP.

1. What sort of IP addresses can you provide?

The IPv6 RFCs had been made by 1996, yet despite support for the protocol being available as standard in almost all modern computing devices, few ISPs seem to offer native connectivity. If you find an ISP that does then the killer question becomes whether they can provide a router that will handle IPv6 packets at your end. If they can’t then you’ll be building your own from a spare box and a couple of network cards. In this case it’s worth asking if they have people who can help you if problems arise and you need to troubleshoot.

If your prospective ISP doesn’t offer native IPv6 you should ask about their migration plans and whether they are providing a 6to4 gateway in the meantime. If the answer is no and you’ll be stuck on the legacy system (IPv4) then find out how many static IPs you can have allocated to your connection and whether they cost extra to provision. This is especially important if you use peer-to-peer systems, play online games, take advantage of SIP-based VoIP or need to connect to VPNs, since making these traverse a NAT device can be a difficult. In the event that only a dynamic IPv4 address is provided I’d recommend looking elsewhere, especially if you’re planning to run any services from your connection.

2. What priorities and limits does your network place on different types of datagram?

Most ISPs use traffic shaping to manage how different packets flow across their network. The aim is to balance factors such as latency, jitter (packet delay variation) and packet loss according to the needs of the application being served by each transfer. Interactive activities such as telecommunications, gaming and media streaming are usually given priority over web browsing and email traffic, which in turn tend to be treated more favourably than bulk transfer protocols such as bittorrent.

A well-designed network management system will affect most users rarely as long as the service isn’t congested, however it’s still useful to be aware of your ISP’s practices so you can understand why your connection is performing as it does, and perhaps so you can schedule heavy usage accordingly. If you plan to make heavy peak-time use of data-hungry or latency-sensitive applications (such as video streaming or online games respectively) you’ll want to pay close attention to how the network manages such traffic. It’s also good to ask what happens in the event of congestion. Does the answer imply the situaiton is handled by deliberate and graceful service-degredation or are random latency-spikes and vanishing UDP packets likely to be the order of the day?

In my view the substance of the answer you get to this question is less important than its frankness (for typical patterns of consumption). Vague responses might suggest a service that performs better on paper than in practice.

I’d avoid any service that takes traffic-shaping beyond its quality of service remit by violating network neutrality. Nobody wants a two-tier internet where the tiers are controlled by a profit-making business.

3. Do you block certain types of traffic or access to certain ports?

ISPs are unlikely to block generic traffic-types from being downloaded to your network completely, though they will often limit downloads in some way (see above), however beware of ISPs that restrict what you can upload from your connection, especially when the transfer originates from the Internet, such as would be expected if you were running a server. Some ISPs make this difficult or impossible, so if you’re planning to host anything over the connection, seek assurances about traffic originating from both ends and travelling in both directions.

Port and traffic blocking is a particular problem with mobile broadband providers, whether your connection is delivered through a dedicated dongle, a separate device such as a MiFi or a mobile phone. Some networks do horrible things to certain types of traffic and it pays to be aware of any restrictions before you commit. The problem I’ve experienced most is that of mobile ISPs preventing me from communicating with my outgoing mailserver by blocking or proxying SMTP ports.

Most ISPs reserve the right to interfere with your data uploads on grounds of network health or self defence if one of your boxen gets rooted and starts sending out spam, DDoS or other malicious traffic. Few would quibble with this given the problems botnets can cause.

4. What network services do you provide to customers?

As your network’s gateway to the outside world your ISP is well placed to offer services that can make your life easier. All will provide DNS resolvers (of varying quality), however some may offer additional services such as NTP, 6to4 tunnels, domain name hosting, email, web hosting, FTP servers, game servers or mirrors of popular software. If such things are of interest then it’s worth asking what’s included.

Geeks crave knowledge and value control. ISPs can cater for this by providing connection details and control interfaces to customers. Ask whether they provide graphs or other details about your connection rate, peak latency, the amount of data you’ve transferred and similarly useful data. Can you adjust your line parameters if you need to? Can you control reverse DNS entries for your connection’s IP addresses? What monitoring and alerting facilities are available?

5. How good is the support for your service?

ISPs are rated on the quality of the support they provide by myriad magazines and review sites however most of these resources are aimed at lay audiences, so while they might indicate the general quality of support provided, power users often need to talk to our ISPs about issues their standard support scripts don’t cover. The ease with which you can get a technical expert on the line doesn’t seem all that important – until you need one! Find out how easy it is to escalate technical queries to the people who can help resolve them.

It’s also useful to know how you can ask for support. Some ISPs reduce costs by limiting support channels to the bare minimum – perhaps an off-shore call centre full of people reading from scripts, or just an email form on their website. Other ISPs communicate with customers through a range of mechanisms: Twitter accounts, IRC channels and even SMS in emergencies. Text-based support can be especially useful for deaf customers or those who use screen-readers. Active user-communities, support forums, company blogs and well-maintained FAQs or knowledge-bases are often a boon to power users so check these out too.

6. Do you intercept traffic?

No ISP will answer yes to this as a straight question as to do so would be to confess to a criminal offence (in the UK, at least). The best ISPs will state explicitly that they will never look at your packets unless they are forced to by legislation or a court order. Some may also reserve the right to inspect the content of traffic crossing their network for fault-finding purposes or to defend against attacks. Such statements should be accompanied by a commitment to disclose each event to those whose data was compromised and to never retain logs for longer than is necessary for the task at hand.

I’d avoid companies that intercept traffic for other reasons – especially if they want to sell profiles of your browsing habits to advertisers – and I’d be suspicious of any company that refuses to rule out such unethical behaviour.

7. Do you censor the connections you sell?

Most UK ISPs censor their Internet connections. They subscribe to the IWF watchlist – a secret list of “bad” URLs compiled by a quasi non-governmental organisation. If your prospective ISP is a subscriber then the URLs on the list won’t be accessible to you. The stated purpose of this system is to block access to child-abuse images however recent legal rulings have forced ISPs to use the same system to censor websites that merely link to files others have made available (allegedly without a licence to do so from the copyright owner) – just like Google does. This is a slippery slope that’s already curtailing freedom of expression in the UK and I believe it should be resisted.

There is another censorship mechanism, much more frequently problematic, which is prevalent on mobile networks (at the time of writing), and which may become a problem on home broadband connections as the UK Government is pushing for it to be rolled out to these too. It’s touted as “adult content filtering” and it’s often switched on by default for new mobile customers. The trouble with these systems is that their definitions of “adult content” are arbitrary and it can be difficult for customers to opt out of them. Finding out if such a system applies to your network, and asking for it to be switched off up front, could save you from having to troubleshoot weird access difficulties later.

The Open Rights Group has a summary of current Internet censorship issues in the UK on its website.

8. How do you handle allegations of copyright infringement?

The Internet works by copying information therefore copyright is the de facto law of the Internet. There’s a war raging at present, between commercial copyright-holding organisations and consumers, for control over who gets to copy what and when. You may have read about the Digital Economy Act, ACTA, SOPA/PIPA, HADOPI and other such oddly-named legislative initiatives. These are all attempts by vested interests in the media industries to buy laws that restore their erstwhile monopolies on the distribution of media. Unfortunately these laws share another undesirable trait: they all have side-effects that curtail our privacy and freedom of expression.

ISPs are caught in the crossfire of this war. The media industries want them to behave as an Internet police force, monitoring the files we share, spotting transfers that look like they might infringe on their copyrights then imposing sanctions on us. Some ISPs take a dim view of this suggestion, arguing that forcing them to threaten their customers and violate their trust is bad for business, and would cost a lot of money to boot.

If you are unlucky enough to be accused of copyright infringement – which can happen regardless of whether you’ve actually downloaded something illegally because the standard of evidence put forward by copyright holders is usually very low – the economic incentives in the UK are such that ISPs are likely to behave as if you are guilty rather than spending time and money finding out the truth of the matter. You could find your contract terminated for breach of an Acceptable Use Policy, your personal details sent to the complaining party without your permission and a civil suit filed against you, all without adequate judicial oversight or due process.

Some ISPs have more reasonable policies in this regard than others. It’s worth checking how such situations would be handled before you commit to a contract – especially if you won’t be the only person using your connection and doubly especially if you plan on running a TOR exit node or an open wifi hotspot.

Did I miss out an important question or get something wrong? Which ISP would you recommend for power users and geeks? Let me know in the comments.

Thanks to @thegreatgonzo, @z303, @djb_ptigga, @kelly_plusnet, @tdobson, @secretlondon, @johnstovin & @owenblacker for their question suggestions.