If instead someone "helpfully" redirects me to something else, then I can't reliably detect the condition. (My home ISP does that to me, and it gripes me to no end.)
Most times I've seen this malicious behaviour, it was "just" a DNS manipulation, i.e. it happend only for domain names not currently found in the DNS. Instead of returning NXDOMAIN, the provider's DNS server happily returned the IP address of a provider-supplied web server that offered some unhelpful search form. Verisign started this malicious behaviour in September 2003, and several providers happily copied it. Bypassing this malicious behaviour is quite easy, just don't use the DNS server(s) of your provider, but some free ones. Google offers 22.214.171.124 and 126.96.36.199, I use them in my DSL router (that acts as name server for my LAN), because my provider "accidentally forgets" my opt-out every few weeks, and I'm quite happy with that setup.
If you see the unhelpful page instead of a 404 page also for URLs with well-known servers, like http://www.google.com/google/does/not/have/this/page, there are essentially two methods left: Either your provider infected your PC with that malware when you installed software for access to your providers dial-up network, or your provider uses a transparent proxy. Booting from a live linux cdrom easily shows what really happens. In the first case, the unhelpful page is gone as soon as you don't use the malware-infected operating system. The second case can be identified by the fact that any web server you connect to sees your request coming from a different address than the one your provider issued to your system. Pages like http://ix.de/ip show you from what IP address your request comes from.
Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)
Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
Read Where should I post X? if you're not absolutely sure you're posting in the right place.
Please read these before you post! —
Posts may use any of the Perl Monks Approved HTML tags:
You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
- a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
Link using PerlMonks shortcuts! What shortcuts can I use for linking?
See Writeup Formatting Tips and other pages linked from there for more info.
| & || & |
| < || < |
| > || > |
| [ || [ |
| ] || ] ||