Link prefetching

[vasa1]

Before starting this thread, I searched the forum for "link prefetching" but got nothing except for this post of mine here.

I didn't know about this at all but once I set up PCTFWP to ask about virtually everything, I realised that such a thing exists.

Firefox has a way to turn it off using about config: but before I try that, I'm curious to know if anyone has and subsequently found that their "user experience" has been adversely affected.

Anyway, here are a few links about link prefetching and opinions on its "morality":

• Link prefetching: http://en.wikipedia.org/wiki/Link_prefetching
• Prefetching by the "don't be evil" gang: http://webaccelerator.google.com/webmasterhelp.html
• How to Disable Firefox Link Prefetching for better Online Security: http://webtoolsandtips.com/make-wind...k-prefetching/

[26Dolphins]

Hi vasa1,

I keep prefetching disabled for quite some of the reasons mentioned on that Wikipedia link you provided, as "the user might visit in the near future" is not a good enough reason for me to keep it enabled.

As for

Originally Posted by vasa1

... found that their "user experience" has been adversely affected....

it all depends on what the acceptable "user experience" level is.
Disabling prefetching may have an impact when one decides to load a "heavy" site, but the degree of it also depends on your system & Internet connection.

Bottom line, you have to try it for yourself, do your usual web surfing and see if there's unacceptable impact, if any.

Cheers,
26Dolphins

[vasa1]

Originally Posted by 26Dolphins

...
Bottom line, you have to try it for yourself, do your usual web surfing and see if there's unacceptable impact, if any.
...

Hi and thanks for answering. I too have turned it off. While it may enhance the browsing experience for those with "unlimited" net usage, those of us with budgets may not want this "experience".

It would be interesting to know the experience of others who use browsers other than Firefox (or its clones).

[torres-no-tan-magnifico]

Originally Posted by vasa1

Hi and thanks for answering. I too have turned it off. While it may enhance the browsing experience for those with "unlimited" net usage, those of us with budgets may not want this "experience".

It would be interesting to know the experience of others who use browsers other than Firefox (or its clones).

Just to say thanks vasa1 for the heads up.

I use FF for most of my browsing and have also turned off prefetching mainly with regard to security. My other browser is SRWare Iron and I have simply unchecked the use DNS pre-fetching box that is accessible via Options>Under the Bonnet.

Have not as yet had time to assess any difference in performance with Iron, and with FF I can't detect any difference.

[vasa1]

Originally Posted by torresmagnifico

...
I use FF for most of my browsing and have also turned off prefetching mainly with regard to security. My other browser is SRWare Iron and I have simply unchecked the use DNS pre-fetching box that is accessible via Options>Under the Bonnet.

Have not as yet had time to assess any difference in performance with Iron, and with FF I can't detect any difference.

Hi Torres, it makes sense that Google's Chrome (and clones) would also facilitate prefetching links since Google's search automatically loads all or part of the first hit and they go on a bit about the user experience in the link I gave earlier.

I hope Google is aware of the fact that not everyone has super connectivity and unlimited usage to appreciate the user experience they wish to provide (unasked).

As far as no difference in performance in FF ... Since I'm using FF (sandboxed) and with always ask set in PCTFWP, it really used to bug (and alarm) me when FF wanted to open a page which I thought was unrelated to where I was at. Now, that's history .

[vasa1]

I got more confused after reading this:
Google Chrome DNS Fetching
and
Controlling DNS prefetching

Now I feel that all that is being prefetched is the IP address. So that should not be a big deal. It doesn't appear that the page content is being prefetched.

But then why are there two entries in Firefox' about:config?

[1.] network.prefetch.next
and
[2.] network.dns.disablePrefetch

While [2.] is clear, what does [1.] do?

[J_L]

Originally Posted by vasa1

I got more confused after reading this:
Google Chrome DNS Fetching
and
Controlling DNS prefetching

Now I feel that all that is being prefetched is the IP address. So that should not be a big deal. It doesn't appear that the page content is being prefetched.

But then why are there two entries in Firefox' about:config?

[1.] network.prefetch.next
and
[2.] network.dns.disablePrefetch

While [2.] is clear, what does [1.] do?

Interesting, especially the Firefox one.
On Iron, it is disabled by default.

Any input on the possible privacy issue? As I search online, most people say it's not an issue, but I'm very concerned about my privacy.

[vasa1]

I should have titled this topic "Prefetching: links and DNS" or something like that because, while it maybe a privacy issue, DNS prefetching is only a very marginal nuisance if it is a nuisance at all but it is different from link prefetching.

And what I seem to encounter most of the time is DNS prefetching. I can't really remember when (the contents of) a page have been prefetched at my expense. I say this because the working definition of link prefetching seems to imply so:

3 Mar 2003 ... Link prefetching is a browser mechanism, which utilizes browser idle time to download or prefetch documents that the user might visit in the ...
https://developer.mozilla.org/en/Link_prefetching_FAQ -

In any case, I've turned off link prefetching but left DNS prefetching on.

[sa1]

Any input on the possible privacy issue? As I search online, most people say it's not an issue, but I'm very concerned about my privacy.

In general with prefetching has no privacy issues, if anything complete prefetching(as in Fasterfox) only increases your privacy because when you download all possible links instead of just the ones you want, it is harder for analytic services to put tabs on your online behaviour. Link prefetching as espoused by Mozilla is neutral in this matter: it neither adds nor subtracts from privacy.

And what I seem to encounter most of the time is DNS prefetching. I can't really remember when (the contents of) a page have been prefetched at my expense. I say this because the working definition of link prefetching seems to imply so:

Link prefetching prefetches documents that web-authors have explicitly marked for prefetching. I think web-authors rarely do so hence you may not have run across it. I don't use Firefox; I'm not sure how common such explicit link tags are.

Fasterfox prefetches all links regardless of will of webmasters. (http protocol disapproves of this.)

DNS-Prefetching, as you may have understood, has nothing to do with the webmaster at all, it just communicates with the DNS Server, and creates minimal traffic.

P.S. It was exam season so sorry for late replies, though of course I don't need to apologize for it.

[J_L]

Originally Posted by sa1

In general with prefetching has no privacy issues, if anything complete prefetching(as in Fasterfox) only increases your privacy because when you download all possible links instead of just the ones you want, it is harder for analytic services to put tabs on your online behaviour. Link prefetching as espoused by Mozilla is neutral in this matter: it neither adds nor subtracts from privacy.



Link prefetching prefetches documents that web-authors have explicitly marked for prefetching. I think web-authors rarely do so hence you may not have run across it. I don't use Firefox; I'm not sure how common such explicit link tags are.

Fasterfox prefetches all links regardless of will of webmasters. (http protocol disapproves of this.)

DNS-Prefetching, as you may have understood, has nothing to do with the webmaster at all, it just communicates with the DNS Server, and creates minimal traffic.

P.S. It was exam season so sorry for late replies, though of course I don't need to apologize for it.

I see, gonna keep it enabled then. Really doubt there's much privacy issues at all when dealing with DNS.