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FAQ 15: Sites result in "Page cannot be found"Category: BlockedIP function | Updated: 12/16/2014 6:55 PM
Visiting web pages results in a "Page cannot be found" or "This page can't be displayed" or "This webpage is not available" error, or web browsing is sometimes slow.
If just blocked content ends up with this error, than either...
- no web server is running at the IP address specified for BlockedIP=
- the site is a HTTPS (secure) site
- the end-user device has obtained a IPv6 address, but the DNS Redirector server is not also reachable at an IPv6 address
If all content ends up with this error, then either...
- the "real" DNS server specified for DNSServerIP= is invalid or unreachable
- a firewall is blocking UDP port 53 to/from the DNS Redirector server
- Verify that you can visit the IP address specified for BlockedIP=
As an example, if BlockedIP=192.168.0.2 in dnsredir.ini then ensure that you can visit http://192.168.0.2 directly in your browser.
If you cannot visit the IP address specified then this error is the result of no website running at that IP address, TCP port 80 blocked by a firewall,
website not running on TCP port 80, or missing web server configuration such as no default document and/or no custom error documents
(as described under Readme: Hosted Pages)
- Try visiting the site as http:// instead of https://
Blocked sites are not reachable by either, although the blocked page is only displayed for http://
This is expected, see FAQ 145.
- Disable IPv6 on the client device and/or turn off any IPv6 DHCP server on the network
Otherwise you will need to assign a valid IPv6 address to the DNS Redirector server, and for ListenOnIP= in dnsredir.ini,
and set that IPv6 address as the default DNS server that clients will use.
- Check that you have specified a working DNS server for DNSServerIP=
As an example, if DNSServerIP=192.168.0.2 in dnsredir.ini then ensure this DNS server works and is reachable using nslookup.
On corporate networks this is normally the IP of your internal or Active Directory (AD) DNS server, see FAQ 91.
- See DNS Test Instructions to determine the fastest upstream DNS servers you should use.
- Ensure the DNS Redirector ListenOnIP= is the only DNS server used by client computers, see FAQ 28.