Ask for the text of the block page, which usually names the problem. Request a review from the filter maker, check your own site for injected code, and ask your host about a clean address.

A blocked page at the biggest client

A commercial cleaning company hears it from the facilities manager at its largest client: staff there cannot open the company's website. They see a page saying the site has been blocked.

From the cleaning company's own office, and from home, the site loads normally. The problem exists only inside the client's building, on the client's network.

Nothing on the website changed, and nobody at the client chose to block it. A filter made the decision, using information the cleaning company has never seen.

How company networks filter websites

Many companies pass all web traffic through a filter, either a device in the server room or a service the network connects to. It checks each site against a database before letting the page through.

The database sorts sites into categories, such as news, shopping or games, and scores each one's reputation. Company policy then blocks some categories, and often anything uncategorised or poorly rated.

The filter's maker builds that database, mostly by automated scanning, and updates it constantly. A business site can be caught without anyone ever looking at it.

Why a business site gets caught

Each has a different fix, so the first job is to find out which one applies, and the block page itself is the best evidence.

Reading the block page

Ask the client's contact for a screenshot or the exact text of the block page. It usually names the category the site was given, and often the product doing the filtering.

Uncategorised or newly registered points to a new site. Suspicious or malicious points to reputation. An unexpected category, such as real estate or travel, points to a scan that misread the site.

The client's IT department can often say more, including whether the block is by category, by address or by a list of approved sites.

Too new to have a category

New domains and new sites often have no category for weeks. Many companies block anything uncategorised, on the reasoning that new sites are a common source of trouble.

Most filter makers have a public page where anyone can look up a site's category and ask for a review. Submit the site with a plain one-line description of the business, then wait for the reply.

Meanwhile, the client's IT department can add the domain to its own list of allowed sites. That fixes the problem for one client, not for every network using the same filter.

A neighbour on the same address

On shared hosting, hundreds of sites can share one server address. If one of them spreads malware or hosts a fake login page, some reputation services flag the whole address.

Every site on that address then inherits the bad reputation, including yours. Lookup services can list the other domains on an address, and a few unfamiliar names among them are normal.

The fix lies with the host: removing or cleaning the flagged site, asking for the address to be delisted, or giving your site an address of its own.

Your own site first

Before blaming a neighbour, rule out your own site. Check Google's Safe Browsing status for the domain and the security issues section in Webmaster Tools.

Look in the page source for scripts loaded from domains you do not recognise, and for links or text that nobody at the business wrote. Outdated software is the usual way such things arrive.

If the site has been compromised, clean it and update it first, then ask for reviews. A review requested while the problem is still there only confirms the block.

A worked example

A relocation consultant in Vancouver helps employees transferred to the city from elsewhere in Canada find homes, choose neighbourhoods and settle in, with most of its work arranged by the human resources departments of larger companies.

This fall it moved to a new domain carrying its new name. Within days, the human resources coordinator at its biggest client reported that the site was blocked at her office.

The block page said uncategorised and named the filtering product. A lookup on that product's public site confirmed it: the new domain had no category at all.

The consultant submitted the site for review, describing it as a relocation services firm, and the coordinator asked her IT department to allow the domain in the meantime.

The old domain, which carried a category, now redirects to the new one, so links sent before the move still work once the review is done.

The review asks the filter's maker to describe the business accurately, and the allowed list covers the gap until it does.

What the host can change

A host can give a site its own address, often offered together with a security certificate, so it no longer shares a reputation with strangers.

It can also move the site to a server with a clean address, deal with flagged accounts, and keep mail sending apart from web hosting.

The counter-case

Sometimes the block is exactly what the client intended. A firm that allows only an approved list of sites, or blocks every site in a category yours genuinely belongs to, will not change for a review.

There, the route is through your contact: ask that the domain be added to the approved list, and give their IT department what it needs to decide.

It is still worth confirming the site is categorised accurately and hosted cleanly. The next client may use a different filter, with fewer exceptions.

Finding out which it is

  1. Ask for the block page, as a screenshot or exact text.
  2. Note the category and any product name it shows.
  3. Look the site up on that product's public review page.
  4. Check your own site for injected code and warnings.
  5. List the other sites on your server address.
  6. Request a review with a plain description of the business.
  7. Ask the host for a clean or dedicated address if needed.

Step one saves the most time. The block page usually says which of the problems you have, and without it every other step is a guess.

Another way a client's office settings change how your site appears, and the one line that asks the browser to use its newest mode, is covered in a new site shown in compatibility view on office computers.

Frequently asked questions

Why can staff at one client not open our website?

Their company network probably filters sites by category and reputation, and the filter has put your site in a blocked category, or given it no category at all.

How do I find out why the site was blocked?

Ask for a screenshot or the exact text of the block page. It usually names the category and often the filtering product that made the decision.

What if the site has no category yet?

Look the site up on the filter maker's public review page and ask for a category. Meanwhile, the client's IT department can allow the domain.

Can another site on our server cause this?

Yes. On shared hosting many sites share one address, and if one is flagged for malware or fake login pages, some reputation services flag the whole address.

What can the host do?

Give the site an address of its own, move it to a server with a clean reputation, deal with flagged accounts, and keep mail separate from the websites.

Should we check our own site first?

Yes. Check Google's Safe Browsing status and Webmaster Tools for security issues, and look for unfamiliar scripts. A compromised site must be cleaned before any review.

West Coast Media Solutions Inc. provides web design, web development, hosting, digital marketing, and business consulting to organisations across Canada, drawing on more than twenty-five years in the field.

Blocked at a client's office?

Send us the block page's text and your site's address, and we will tell you which problem it is and what to change.

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