|Answering questions about the Cerberus web content filter system.
- How much does this feature cost?
- How does a caching proxy server differ from my browser's cache?
- Does this mean 'realtime' websites like the BBC News site or eBay will no longer contain live information?
- Are your built-in lists incomplete?
- Why do I have sites blocked when I do not want them to be?
- When I have advert filtering enabled I occasionally cannot get to websites and instead get clearpixel.gif. Why?
- Why does Google Images still shows images of an adult nature?
- When I mistype a domain why do I see a Metronet error page?
- I Use Windows 98SE or Windows ME and Cerberus causes windows update to stall with "Windows Update is looking for available updates... 0% complete"
- Does the content filtering work with OnSpeed?
- Is there a way to force people to use the proxy server?
- Why is your advert filtering is not compatible with MSN toolbar?
- When advert filtering is enabled, why do many links on the BBC website suffer from the 'clearpixel.gif' issue?
- We block instant messenging traffic at the firewall however now some of our employees are tunneling through using the proxy server! How do I stop this?
- I am using the proxy as a workaround to a remote logon block however I need to access the secure website on that IP, is there a fix?
- I have found a bug!
1. How much does this feature cost?
Nothing, it comes free as part of our broadband service and is available to all our existing and new broadband customers.
2. How does a caching proxy server differ from my browser's cache?
The main advantages of a caching proxy server is that usually there is more than one person using it, which increases the chance that requested content will already be present in the cache. Your browser's cache can only provide content that you have already visited.
3. Does this mean 'realtime' websites like the BBC News site or eBay will no longer contain live information?
No, the proxy server is told by the websites it visits how long it should remember the page visited for, or the last time the page was updated. Therefore, live pages should only be cached for a very short period of time, if at all.
4. Are your built-in lists incomplete?
The pre-built lists provide a good level of filtering, but they cannot be exhaustive because the Internet is such a huge, ever-changing environment.
There will always remain the chance that some content will get through that should have been filtered by a list. Remember that you can create your own lists to account for sites that are getting through the filter.
5. Why do I have sites blocked when I do not want them to be?
As in question four, the lists are not perfect, so there will always be the chance that filter rules will accidently block legitimate websites. If you need to access a blocked site, you should create a custom whitelist in which you can place any sites that you want to unblock.
6. When I have advert filtering enabled I occasionally cannot get to websites and instead get clearpixel.gif. Why?
This may be caused by sites that show adverts inside an IFRAME where access restrictions will limit the whole site, not just the advertisment content. To solve this problem we recommend that you use a custom list to open access to the blocked site.
7. Why does Google Images still show content of an adult nature?
The web content filter works by blocking sites rather than specific content. Therefore, the only way of blocking adult content on Google Images would be to blacklist the whole site. In this instance we recommend that you use the site's preferences to filter mature content.
8. When I mistype a domain why do I see a Metronet error page?
This is the normal way that the web content filter handles invalid URL requests, and helps speed up browsing.[/LINK]
9. I Use Windows 98SE or Windows ME and Cerberus causes Windows Update to stall with "Windows Update is looking for available updates... 0% complete"
If this happens, disable your proxy service until your Windows update is complete. Otherwise you can tell your computer to trust several Microsoft sites outright with no question. You do this by going to Tools>Internet Options>Security>Trusted Sites>Sites and enter the following sites after unchecking 'Require server verification (https:) for all sites in this zone':
10. Does the content filtering work with OnSpeed?
No, because OnSpeed works with a different proxy server which provides increased speed performance, but doesn't support web content filtering. Also note that systems like WebDAV, iDisk and Microsoft Frontpage-like applications also will not work through the web content filter. You should configure any content managing software (such as WebDAV, iDisk and Frontpage) to not use the proxy server.
11. Is there a way to force people to use the proxy server?
In the Advanced Instructions we give instructions on how to configure your firewall to force the proxy server to be used.
12. Why is your advert filtering not compatible with MSN toolbar?
This is because MSN Toolbar links through several advertising sites to function. You will need to create a whitelisting custom list containing:
13. When advert filtering is enabled, why do many links on the BBC website suffer from the 'clearpixel.gif' issue?
The BBC link to external websites works by bouncing a redirect off one of moreover.coms servers (to gain some minor advertising and marketing statistics revenue). To work around this, create a whitelisting custom list for *moreover.com/*
14. We block instant messenging traffic at the firewall.
However, now some of our employees are tunneling through using the proxy server! How do I stop this?
If your employees configure their instant messenging clients to use our proxy server they would technically be able to bypass any firewall rules you might have in place. You can add a blacklist containing:
Protocol URLs to blacklist
15. I am using the proxy as a workaround to a remote logon block however I need to access the secure website on that IP, is there a fix?
The automatic proxy configuration file we use to tell browsers when to use the proxy server contains instructions to not use it for secure connections. We do this because usually there is no point, as we cannot cache secure data. However, you should use the proxy server for secure websites.
If you use the 'manually configure proxy server' approach, specify for both HTTP and HTTPS connections to use proxy.metronet.co.uk on port 3128. You should find you can then access the secure website part of the logon blocking server.
16. I have found a bug!
Please use Contact Us to report your findings.
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