web caching issue

[subgenius]

I work in web development for a small company, and another developer and myself made separate updates to a website on Monday. But for some reason, I can't see some of the changes that were made when I'm at work, but I have seen the updated pages on another computer. I'm running OS X at work and get the same result on different browsers, and the problem also occurs on other computers in my office (both Macs and PCs). I've emptied the cache, history, cookies, and anything else with a trash can about 20 times, so I feel pretty sure that that's not the issue either.

My best theory at this point is that it has something to do with our Charter cable service or something else in between the web hosting company and my computer. I've e-mailed friends in different states, and they're seeing the updated pages, and none of them use Charter for Internet access, which leads me to believe that somehow, Charter is the source of the problem.

I'm obviously not a networking person, so I was wondering if anyone had any ideas as to what was going on, and do ISPs cache websites somewhere in between the web hosting company and my desktop?

 

[HKSturboKID]

Well my guess is that you company probably use some kind of web cache device where one of them is updated and the redundant one still caching the old pages. Have your network admin flush out the caches and see what happens. Also try to do a tracert from the pc that is seeing the old pages to see if the the route is the same as the pc that is seeing the updated pages.

 

[Garion]

The good news: A lot of ISP use transparent caching devices to save bandwidth and improve customer response time.

The bad news: The caches only do what the website tells them to, in terms of caching objects.


In other words, if it's getting cached and it shouldn't be, it's not Charter's problem, it's yours (or whomever runs your website). Cacheability of a site is set on the web server - All a web cache does is obey the rules that you publish along with your site.

There's a good tutorial and explanation of this at mnot. Give it a read and it will explain why this is happening and how to prevent it. Some info is old (they talk about IIS4), but most is still very pertinent.

- G

 

[subgenius]

Thanks for your help, HKSturboKID and Garlon. You're both right, I'm wrong. I actually meant something more along the lines of network caching, when I said web caching. I went on Google and found this webpage that talks about network caching:

http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/net_cach.htm#xtocid1

and thought that that might be the problem, but I think the problem is that the computers in my office are poorly networked. There are only seven of us altogether and I think when the network was initially setup, the computers were linked room to room in a big chain.

Can anyone recommend any resources or networking models (ie Client-Server network) that would be useful for a small business like ours? I'm guessing that the problems we encounter will only get worse if we don't restructure the way we're networked together.

 

[wlee]

As far as I know, Charter does not ( yet ) use inline caching. Anyway, try adding a question mark " ? " to the end of the URL you want to load. E.G., " http://www.anandtech.com/? " to force an un-cached load. You might also check out the Charter Communications forum at DSLReports.com It's also posible that your web host uses Akamai cache servers to load balance based on region. It may take time for an update to proliferate.

 

[Garion]

Originally posted by: subgenius
Thanks for your help, HKSturboKID and Garlon. You're both right, I'm wrong. I actually meant something more along the lines of network caching, when I said web caching. I went on Google and found this webpage that talks about network caching:

http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/net_cach.htm#xtocid1

and thought that that might be the problem, but I think the problem is that the computers in my office are poorly networked. There are only seven of us altogether and I think when the network was initially setup, the computers were linked room to room in a big chain.

Can anyone recommend any resources or networking models (ie Client-Server network) that would be useful for a small business like ours? I'm guessing that the problems we encounter will only get worse if we don't restructure the way we're networked together.

Looking at that doc, web caching == network caching. Cisco likes to throw their own terms around, despite what the industry uses.

If you're not sure about how your network is structured, post more details here (probably in another topic) and there's lots of folks who will help out.

- G