DNS warning updating outdated

[graziosi.angelo@…]

Recently I get this warning updating outdated ports:

$ sudo port upgrade outdated
[...]
Warning: Your DNS servers incorrectly claim to know the address of nonexistent hosts. This may cause checksum mismatches for some ports.
[...]

I am not sure, but it seems to me that this occurs since the upgrade from 2.1.3 to 2.2.0.

Usually the upgrade, after issuing that warning, is fine.

Ciao, Angelo.

[larryv (Lawrence Velázquez)]

There’s no problem here. Just watch out for checksum mismatches if a port tries to fetch a nonexistent file. (See also #25128 and #33930, if you’re curious.)

[graziosi.angelo@…]

Replying to larryv@…:

There’s no problem here. Just watch out for checksum mismatches if a port tries to fetch a nonexistent file. (See also #25128 and #33930, if you’re curious.)

Perhaps it is as you write, but it does not seem normal that, for at least two years, I NEVER see that warning and now, say in the last two week, I get SYSTEMATICALLY that warning and ONLY for the first port to be upgraded, whatever it is.

Angelo

[neverpanic (Clemens Lang)]

That's because the test is new since r99755, which wasn't in any released version but 2.2.0. Try opening invalid-host.macports.org in a Browser and see what happens. If you don't see an error message printed by your _browser_, you're affected by the problem. As the warning says, this might not always cause problems for you.

[graziosi.angelo@…]

Replying to cal@…:

That's because the test is new since r99755, which wasn't in any released version but 2.2.0. Try opening invalid-host.macports.org in a Browser and see what happens. If you don't see an error message printed by your _browser_, you're affected by the problem. As the warning says, this might not always cause problems for you.

Let's see if I have understood..

With MacPorts 2.2.0 has been introduced a test which tries to load a not valid host (invalid-host.macports.org), so that the test HAS success if it PRODUCES an error (indeed when I put invalid-host.macports.org in the address bar of Chrome, I got an error). And this is flagged to the user with that warning.

So, in short, the warning really means "OK, you have a good connection etc.."

Is that interpretation right?

Ciao, Angelo.

[neverpanic (Clemens Lang)]

Replying to graziosi.angelo@…:

With MacPorts 2.2.0 has been introduced a test which tries to load a not valid host (invalid-host.macports.org), so that the test HAS success if it PRODUCES an error.

Correct so far. If the lookup of invalid-host.macports.org does NOT fail, there is a potential problem with your setup.

(indeed when I put invalid-host.macports.org in the address bar of Chrome, I got an error). And this is flagged to the user with that warning.

It depends what kind of error you get. If it's the error message usually printed by Chrome (​http://files.neverpanic.de/chrome-dns-error.jpg) then your connection is fine and you should not see this warning. If you see a different page (usually with your ISP's logo and a search form) your DNS servers do not correctly indicate that this domain does not exist, which might lead to problems when automatically downloading files.

So, in short, the warning really means "OK, you have a good connection etc.."

No. If you see the warning, there probably is something wrong with your connection.

Just to make sure, let's verify this is actually the case. Please run the following command in a terminal and paste its output:

/usr/bin/host invalid-host.macports.org

[graziosi.angelo@…]

Replying to cal@…:

Replying to graziosi.angelo@…:

With MacPorts 2.2.0 has been introduced a test which tries to load a not valid host (invalid-host.macports.org), so that the test HAS success if it PRODUCES an error.

Correct so far. If the lookup of invalid-host.macports.org does NOT fail, there is a potential problem with your setup.

(indeed when I put invalid-host.macports.org in the address bar of Chrome, I got an error). And this is flagged to the user with that warning.

It depends what kind of error you get. If it's the error message usually printed by Chrome (​http://files.neverpanic.de/chrome-dns-error.jpg) then your connection is fine and you should not see this warning. If you see a different page (usually with your ISP's logo and a search form) your DNS servers do not correctly indicate that this domain does not exist, which might lead to problems when automatically downloading files.

So, in short, the warning really means "OK, you have a good connection etc.."

No. If you see the warning, there probably is something wrong with your connection.

Just to make sure, let's verify this is actually the case. Please run the following command in a terminal and paste its output:

/usr/bin/host invalid-host.macports.org

It prints:

$ /usr/bin/host invalid-host.macports.org
invalid-host.macports.org has address 212.48.8.140
Host invalid-host.macports.org not found: 3(NXDOMAIN)
Host invalid-host.macports.org not found: 3(NXDOMAIN)

Sincerely, I don't understand what is wrong with my connection. I work with it since 2004 without big problems..

Ciao,

Angelo.

[graziosi.angelo@…]

Replying to graziosi.angelo@…:

Replying to cal@…:

Replying to graziosi.angelo@…:

With MacPorts 2.2.0 has been introduced a test which tries to load a not valid host (invalid-host.macports.org), so that the test HAS success if it PRODUCES an error.

Correct so far. If the lookup of invalid-host.macports.org does NOT fail, there is a potential problem with your setup.

(indeed when I put invalid-host.macports.org in the address bar of Chrome, I got an error). And this is flagged to the user with that warning.

It depends what kind of error you get. If it's the error message usually printed by Chrome (​http://files.neverpanic.de/chrome-dns-error.jpg) then your connection is fine and you should not see this warning. If you see a different page (usually with your ISP's logo and a search form) your DNS servers do not correctly indicate that this domain does not exist, which might lead to problems when automatically downloading files.

So, in short, the warning really means "OK, you have a good connection etc.."

No. If you see the warning, there probably is something wrong with your connection.

Just to make sure, let's verify this is actually the case. Please run the following command in a terminal and paste its output:

/usr/bin/host invalid-host.macports.org

It prints:

$ /usr/bin/host invalid-host.macports.org
invalid-host.macports.org has address 212.48.8.140
Host invalid-host.macports.org not found: 3(NXDOMAIN)
Host invalid-host.macports.org not found: 3(NXDOMAIN)

Sincerely, I don't understand what is wrong with my connection. I work with it since 2004 without big problems..

OK, I have tried also this:

$ host ____.org
____.org has address 212.48.8.140
Host ____.org not found: 3(NXDOMAIN)
Host ____.org not found: 3(NXDOMAIN)

$ host axbc.com
axbc.com has address 81.169.145.157
axbc.com has IPv6 address 2a01:238:20a:202:1090::144
axbc.com mail is handled by 5 smtpin.rzone.de.
axbc.com mail is handled by 10 mailin.rzone.de.

$ host axbcdefg.com
axbcdefg.com has address 212.48.8.140
Host axbcdefg.com not found: 3(NXDOMAIN)
Host axbcdefg.com not found: 3(NXDOMAIN)

and searched for 212.48....

For what I have understood (​http://punto-informatico.it/2348608/PI/News/dns-promozionali-alice-irritano-utenti.aspx), it seems the result of a promotional policy of the provider. In short, the user typing a not existent site is redirected to a page (212.48....) proposing some alternative suggestions.

Some year ago (the cited article, I am afraid it is in italian.. :( ) the situation was worse because the user was redirected to a page with games, pubblicity etc..

it seems that I have to live with the MacPorts warning... :-(

Ciao,

Angelo.

[neverpanic (Clemens Lang)]

Replying to graziosi.angelo@…:

In short, the user typing a not existent site is redirected to a page (212.48....) proposing some alternative suggestions.

Yes, that's exactly the situation this test is supposed to detect.
Why is this a problem? Well, sometimes mirrors MacPorts tries to use cease to exist. Normally, DNS resolution would fail and MacPorts would just gracefully try the next mirror. However, in this case, DNS resolution actually does not fail and MacPorts continues to download the file from this server. Since MacPorts tries to find the fastest server out of a given set of mirrors and these "services" are often run by providers which are rather close to you, MacPorts often ends up trying to use these "mirrors", downloading an incorrect file and aborting installation. This warning is to remind you that this might happen; you should keep it in mind if you see a checksum error.

it seems that I have to live with the MacPorts warning... :-(

Most ISPs offering this "service" have a way to turn it off in their control panel settings. You might want to check that (or even call them and tell them to stop trying to be "helpful"). ISPs can also not force you to use their DNS servers – there is a series of alternative DNS servers available that you could configure your setup to use instead to work around this problem, if you want to.

[mkae (Marko Käning)]

Cc Me!