nesdev.com
http://forums.nesdev.com/

URL Redirection
http://forums.nesdev.com/viewtopic.php?f=14&t=8753
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Author:  NESHomebrew [ Sat Mar 24, 2012 9:09 am ]
Post subject:  URL Redirection

http://Nesdev.com now points to the wiki, and http://nesdev.com still goes to the old homepage. Is this just a glitch, or should I change my favourites? http://nesdev.com/bbs no longer works as a shortcut to the forums either *sad panda*

*edit* seems like it was temporary... as now it seems to be fine...

Author:  koitsu [ Sat Mar 24, 2012 11:19 am ]
Post subject: 

No changes have been made on the server in weeks, if not months. We do no form of caching either, and we do not use load balancing of any kind.

Technical details:

nesdev.com points to 72.20.98.77
www.nesdev.com points to 72.20.98.77
nesdev.com points to 72.20.98.77
wiki.nesdev.com points to 72.20.98.75

nesdev.com will always point directly to the main nesdev site (never the Wiki). Ever. Period.

nesdev.com permanently redirects any URL to http://nesdev.com/, so a visit to http://nesdev.com/bbs/ will redirect you to http://nesdev.com/bbs/

The Wiki portion of nesdev is on a completely separate IP address. If you were to connect to 72.20.98.77 and issue a GET request and a Host: header of wiki.nesdev.com, you will get a very informative error page that tells you "you're doing something naughty" and give you details about what it is your web browser submit to our server.

I'll see if I can figure out what happened based on your IP address and the time frame you submit GET requests to our server, but overall this does not look to be a problem with any part of our infrastructure.

Author:  koitsu [ Sat Mar 24, 2012 11:23 am ]
Post subject: 

When the problem happened, were you visiting the site from the IP address 207.195.xxx or 24.89.xxx? It seems you've logged into the BBS from different IP addresses so I want to make sure I'm looking for the proper/relevant IP address in our logs.

Edit: Looks like 24.89.xxx, since there's nothing in our logs today for 207.195.xxx.

Author:  koitsu [ Sat Mar 24, 2012 11:28 am ]
Post subject: 

You made no requests to our webserver from the hours of 06:34 PDT until 08:54 PDT (so about 2.5 hours). These are the requests in our logs -- and we log everything, so any oddities on the webserver side would have shown up here.

These two GET requests are literally in sequential order -- nothing from your IP address arrived at our webserver between these two requests.

Code:
24.89.xxx - - [24/Mar/2012:06:34:59 -0700] "GET /bbs/templates/subSilver/images/icon_mini_search.gif HTTP/1.1" 200 237 "http://nesdev.com/bbs/" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_2) AppleWebKit/534.52.7 (KHTML, like Gecko) Version/5.1.2 Safari/534.52.7"
24.89.xxx - - [24/Mar/2012:08:54:48 -0700] "GET / HTTP/1.1" 200 22313 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_2) AppleWebKit/534.52.7 (KHTML, like Gecko) Version/5.1.2 Safari/534.52.7"


The requests also landed at and were answered by the 72.20.98.77 IP address.

Based on the fact that you posted the problem at 09:09 PDT, I would say the issue was with your ISP, some kind of man-in-the-middle compromise, or a very serious/catastrophic router bug. I do not believe the problem was DNS-related (barring things like severely broken DNS caching proxies) because as I said, the wiki and main nesdev sites are on two completely different IP addresses.

If I had to take a guess, I'd say your ISP (Access Communications in Canada) either uses a form of transparent HTTP caching/proxying or does some form of transparent layer 7 packet manipulation and their shit broke badly for a couple hours. Whether or not you saw anomalies to other websites during that ~2 hour timeframe is irrelevant. I have seen caching proxies (transparent or configurable) completely break before, and in very bad ways. ISPs here in the states, like Comcast, have screwed things up similarly and despite customers noticing the problem the issue disappears mysteriously a few hours later with no mention of it anywhere.

TL;DR -- whatever happened was purely unrelated to anything hosted here.

Author:  NESHomebrew [ Sat Mar 24, 2012 12:10 pm ]
Post subject: 

Wow, that really is messed up. I also wonder if it could have been a safari glitch. I love the hardware on this laptop, but I have ZERO faith in apple software.

The weirdest part was that nesdev.com went to the wiki and nesdev.com/bbs didn't go anywhere. I don't have much faith in my isp either, but for the price I pay it's the fastest I can get around here.

Author:  koitsu [ Sat Mar 24, 2012 6:55 pm ]
Post subject: 

Understood. I have no way to determine if it was a Safari problem or not, but I would strongly doubt it. The fact that the Wiki and main nesdev site (which includes the BBS) are on different IPs indicates more than likely something very erroneous was going on upstream for you, or on a packet level. If I had to take a wild guess, I'd say a very, very badly broken DNS server or some kind of transparent HTTP proxy/cache.

Like I said, we didn't see any HTTP requests from your IP for over 2 hours, yet there were lots of other people visiting both sites (wiki and the nesdev sites) during that time frame. I'm forced to believe the issue was somehow centric to you or your ISP, sad to say. :(

Author:  koitsu [ Mon Mar 26, 2012 9:01 am ]
Post subject: 

By the way, when/if the next time this happens, I recommend you immediately run ICSI Netalyzer (you'll need Java). It does things like examine whether or not there's transparent caching going on within your ISP, and similar issues with DNS. The results may not make much sense to you, but they will to me.

Here's an example run for sake of what gets analysed.

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