[Dapp]

Hello
I don't know why this happs:

#test
#this works:
127.0.0.1 apple.com
#this not:
127.0.0.1 www.apple.com
any idea?

thanks

[Kristoff]

The way you have it...if both of them are in the file, it stops at first resolution.

The correct syntax would be:

127.0.0.1 apple.com www.apple.com localhost

[mrchin]

Just for my knowledge, hosts file allows you to apecify or prevent access to ceertain sites, right?

I had someone show me that he added about 50-100 items to this file to block pop-ups apparently. I did tell him to just turn it on in safari, but he thought he'd use his Unix instead. Afterwards, his mail and ichat apps took a minute to launch on first launch after boot. Subsequent launches were ok, but I did finally pinpoint the issue to this file. Upon, resetting it back to an original file with limited text, issue resolved.

Could there be a bad command in there that was hanging any internet app? (not browsers though). Or just too many entries?

[Johnny_B]

It isn't a good idea using /etc/hosts for banner blocking

[Kristoff]

No, you got it all wrong.

/etc/hosts is used solely for name resolution.
using it will just "short circuit" DNS resolution (depending on how lookupd is configured)

Now, you can trick your computer and prevent sites from loading by mapping something like

127.0.0.1 ad.server.com
127.0.0.1 something.else.com


in which case any requests to either ad.server.com or something.else.com would just go to your localhost.

/etc/hosts is not used for allowing or denying hosts access in or out of your machine.

[spiky_dog]

Originally posted by Kristoff:
/etc/hosts is not used for allowing or denying hosts access in or out of your machine.

well, if he didn't specify a dns server then he could selectively allow access by only defining allowed sites in /etc/hosts (or netinfo's /machines directory more ideally)...

[mrchin]

so are we saying that adding 127.0.0.1 whatever.com for said sites will block their appearance?

[Kristoff]

No, that's not what I said.

By default, OS X has lookupd to get info from NetInfo, not from flat files, unless you change the lookupd configuration.

If you want to block sites, you need to add a rule to IPFW.

ipfw add deny tcp from <blocked.domain> to any

etc, etc....

ipfw is what blocks sites. /etc/hosts is for name resolution

[spiky_dog]

Originally posted by mrchin:
so are we saying that adding 127.0.0.1 whatever.com for said sites will block their appearance?

your syntax is not correct, but yes, that's why there are lists of ad servers pre-mapped to 127.0.0.1 that one can download and import. i run one, for example, and imported it into netinfo.

http://www.macwrite.com/criticalmass...ts-panther.php

[Kristoff]

I still don't get why you would bastardize lookupd when ipfw is the tool designed for that purpose....

(and that syntax is correct)

address hostname1 hostname2 alias1 alias2, etc

[spiky_dog]

Originally posted by Kristoff:
I still don't get why you would bastardize lookupd when ipfw is the tool designed for that purpose....

(and that syntax is correct)

address hostname1 hostname2 alias1 alias2, etc

ah, so it is. i had it in my head that it was backwards

anyway, using host files to combat ads is common because others take the time to craft and populate host files for the lazy amongst us, namely me. then i download them, import them into netinfo, and enjoy the result.

[Kristoff]

but, you could just as easily download an IPFW ruleset and thereby use the proper application (a firewall).

But, whatever lifts your skirt.

[genevish]

Originally posted by mrchin:
so are we saying that adding 127.0.0.1 whatever.com for said sites will block their appearance?

Essentially, yes. 127.0.0.1 maps to the IP address of your own machine. So, when a web page asks for an ad from ads.server.com, your hosts file would tell your browser to get it from your own machine. Since your machine does not have that ad on it, the ad will not appear. It's not really the way it was intended to work, but it gets the job done.

Incidentally, this is a good joke to play on someone. If you know their homepage is listed as my.yahoo.com, for example, you can map requests for my.yahoo.com to go to www.microsoft.com or something. They won't know what happened...

[Kristoff]

Why would you associate with people who would let you have unfettered access to anything in their /etc directory?

[zzzmarcus]

Originally posted by Kristoff:
Why would you associate with people who would let you have unfettered access to anything in their /etc directory?

good point.