A couple of questions for readers.
Has anyone tried to access my other history website (http://shhistory.port5.com/) in the last couple of weeks and got a ‘Cannot find server’ or similar message? Or, alternatively, have you managed to get in OK? I think there may be problems with the host (Portland), but I don’t know if it’s terminal. (There aren’t many pages at that site and I’ve been thinking of transferring them to EMR for a while. So this may be the time to get it sorted out…)
Secondly, I’ve had an email from a reader who has visited this site and found a ‘Hotlinking forbidden’ sign. (I don’t know any details of whereabouts in the site yet.)* Has anybody else had this experience? I have CPanel set up to bar hotlinking images from outside sites, but it shouldn’t cause any internal problems, should it? Anybody got any ideas how it might happen?
Update: I’ve read this online article that suggests you can get problems that are to do with the ‘HTTP_REFERER environment variable’. The, erm, what? I’m not quite grasping what it’s saying here, I have to confess. (Look, I got 28% in the Nerd Test! I am useless at these things! I don’t even know what a graphing calculator is!)
* Another update: Got some more information about her problem.
I did a google search for ‘Early Modern’ and (probably) ‘legal’ or ‘trial’, and found your site as one of the references. Simply clicking on the address [probably this page: http://www.earlymodernweb.org.uk/themes/crime.htm] witin Google led me to a page which had a background saying ‘hotlinking banned’ over and over again, plus a banner in the
middle – very large, at about a third of the screen – with the same message. I tried clicking on a link on that main page [http://www.earlymodernweb.org.uk], but the same thing happened there. My next ploy was to try copying your address into the address bar of my browser, to go directly to the site, but this had the same result.
Eek! Does that mean anything to anybody? I think she’s probably using IE (but IE tests out fine here anyway).
16 comments on “Are you having any problems around here?”
I’ve had no problems with access. I hope this helps you to locate the trouble.
- the ‘HTTP_REFERER environment variable’
‘Environment variables’ are short pieces of data carried in your communication with websites. So, for example, when you request a webiste through your browser, your computer will generally send such information as the type of browser you’re using, the operating system, etc. A lot of your web statistics are composed from these environment variables (e.g. percentage of people using internet explorer who visit your website), but they are also frequently used by CGI (c_ommon g_ateway i_nterface) scripts, such as those written in Perl or PHP (or wll, anything) – indeed, web statistics collectors are usually CGI scripts.
Put simply, ‘HTTP_REFERER’ is another of these little bits of information sent to the webserver you are communicating with, and should usually contain the address of the website which linked (hence ‘referer’) you to the site you’re now going to/requesting information from. If you use scripts to prevent hotlinking of images, what THEY would usually do is check to see the HTTP_REFERER of the server which is asking for the image, and if it’s not the site you’ve specified (usually, your site), then they reject the request. So if I was to attempt to get one of your images from ifanything.org, it would HTTP_REFERER would have the value ‘http://www.ifanything.org/nonexistentpage.htm’, and the script would ask ‘is HTTP_REFERER equal to ‘http://www.earlymodernweb.org.uk’ (or whatever server), the result would come back ‘false’, and it would decline the request.
Hope this helps. Those even geekier than me please step in to slap me down if you disagree on any points! As for problems, I’d have to know a little more about what things you’re specifically using to help.
OK, think I’m following you so far, Rob.
Now, this is what the article I linked to says.
“If you do decide to implement any of these anti-leaching techniques (ie barring hotlinking) on your site then you should be aware that you could be blocking otherwise legitimate requests. A surfer who chooses to munge their browsers HTTP_REFERER may have come from a valid page – but if they don’t pass any recognised values to the server they will be stopped from viewing your images or downloading your files.”
For a start, what does “munge” mean? (It sounds disgusting to me.) And how does the HTTP_REFERER of a surfer’s browser come into this? From what you’re saying, I thought the important thing is for the *website’s server* to match up.
Hehe. “Munge” really does sound disgusting, and I do worry about those that used it. It’s usually used regarding email addresses, such as my own “rob at ifanything dot org” – it basically means obfuscating it. You could change your settings in a complex manner to send incorrect or obfuscated environment variables, I guess, although why you’d do this (other than for fairly ‘extreme’ privacy reasons) I don’t know.
In most hotlinking-barring methods I can conceive of, it would be about the website’s server. But if you’ve “munged” your environment variables then the script, at the point where it asks “is HTTP_REFERER equal to (valid server)?” would get a garbled response and presume “No!” But like I said, I don’t know when or how people “munge” their environment variables and wouldn’t presume that it was very common AT ALL. In other words, this may well be the problem, but might equally be something else you (& I) haven’t thought of yet. If it *is* the problem, and it’s as uncommon as I’m guessing, then I wouldn’t be *too* worried. But maybe someone else knows better, and loads fo people “munge their variables” (what a phrase!) all the time?
Oops! Forgot to say:
“how does the HTTP_REFERER of a surfer’s browser come into this”
The browser is what generally sends the HTTP_REFERER–containing the server–to the website. So it would be the browser that you’d setup to “munge” (argh!) your environment variables.
Mungey. Thanks Rob. Although I have no idea if this is my reader’s problem, it’s sounding less likely – it sounds to me hardly the sort of thing you’d do by accident or without knowing about it.
Still, since I’m not getting a flood of commenters with the same problem, perhaps what’s happening to her is something very unusual…
What does “obfuscating” mean??
*dumb little sis*
Google says:
“to make obscure or unclear”
Well, that ‘un’obfuscated that, didn’t it!! LOL
Forgot to say thanks!
teehee!
Ignore my lil sis. She’s just iggerant. It comes from living in a Suffolk village where they all have two heads and twelve fingers and like sheep.
Coming from an Essex town where they all have two white trainers and high pitches like bats, I can only sympathise!
Although I have received the “hot-linking forbidden” error in the past, it has been so long that I don’t remember exactly how it occurred. It was either a link from Cliopatria, or a google search for the site froma location I don’t have it bookmarjed from. I think.
I did just try accessing your other website at http://shhistory.port5.com/, and it worked just fine.
But I can’t get through to it! That is really odd (I’ll have to try from the office computer next week, I suppose). Still, email (mostly junk of course) is coming through on that account so *something* must be working.
Says my big sis who’s gone to a COUNTRY that is reknowned for it’s ‘liking’ of sheep