Problem with a domain that seem to respond correctly

Hi, I'm using this lib on a daily basis. I have found a problem with the domain bourdette (.com).

This domain can't be checked because there is an exception in the RECV function. With telnet it seems to work fine.

Does anyone can help?

Thanks, Fabio Chelly

Turn on debug to see the exact output/exception? When using telnet (which you say works fine), are you connecting from the same machine/host as the script or a different one?

Hard to tell anything else without more details really...

I tried to connect from the same IP machine with telnet (a linux centos server).

I tried to follow the problem step by step:

After the HELO, in the expect(), the first RECV works fine but the second one (located in a while loop) triggers a Timeout exception.
I tried to catch this exception (in the expect() while loop) and your library has been able to go further but in the end, every response code was out of sync (shifted one command further) : for instance, I had a 550 response code for the QUIT command (it was the response code of the previous RCPT TO).

Maybe the problem is that for this domain (bourdette.com), I get a 220 response after the HELO too soon (this domain is very fast). So maybe I get a timeout because the response has already been sent?

You can try by yourself with anything@bourdette.com

Cordialement, Fabio Chelly

2017-09-13 15:26 GMT+02:00 zytzagoo notifications@github.com:

Turn on debug to see the exact output/exception? When using telnet (which you say works fine), are you connecting from the same machine/host as the script or a different one?

Hard to tell anything else without more details really...

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This is what I get, tested using:

<?php

require 'smtp-validate-email.php';

$from = 'a-happy-camper@campspot.net'; // for SMTP FROM:<> command
$emails = array(
    'anything@bourdette.com',
);

$validator = new SMTP_Validate_Email($emails, $from);
$validator->debug = true;
$smtp_results = $validator->validate();

print "\n";
var_dump($smtp_results);

Output:

MX records (bourdette.com): Array
(
    [smtp.bourdette.com] => 10
    [bourdette.com] => 0
)

Connecting to smtp.bourdette.com:25
Connected to smtp.bourdette.com:25 successfully
<<<recv: 220-zimbra.bourdette.com ESMTP Postfix

<<<recv: 220 zimbra.bourdette.com ESMTP Postfix

send>>>: EHLO campspot.net
<<<recv: 250-zimbra.bourdette.com

<<<recv: 250-PIPELINING

<<<recv: 250-SIZE 30000000

<<<recv: 250-VRFY

<<<recv: 250-ETRN

<<<recv: 250-STARTTLS

<<<recv: 250-ENHANCEDSTATUSCODES

<<<recv: 250-8BITMIME

<<<recv: 250 DSN

send>>>: MAIL FROM:<a-happy-camper@campspot.net>
<<<recv: 250 2.1.0 Ok

send>>>: NOOP
<<<recv: 250 2.0.0 Ok

send>>>: NOOP
<<<recv: 250 2.0.0 Ok

send>>>: RCPT TO:<anything@bourdette.com>
<<<recv: 550 5.1.1 <anything@bourdette.com>: Recipient address rejected: bourdette.com

Unexpected response to RCPT TO: 550 5.1.1 <anything@bourdette.com>: Recipient address rejected: bourdette.com

send>>>: NOOP
<<<recv: 250 2.0.0 Ok

send>>>: RSET
<<<recv: 250 2.0.0 Ok

send>>>: QUIT
<<<recv: 221 2.0.0 Bye

Closing socket to smtp.bourdette.com:25
array(2) {
  ["anything@bourdette.com"]=>
  bool(false)
  ["domains"]=>
  array(1) {
    ["bourdette.com"]=>
    array(2) {
      ["users"]=>
      array(1) {
        [0]=>
        string(8) "anything"
      }
      ["mxs"]=>
      array(2) {
        ["smtp.bourdette.com"]=>
        int(10)
        ["bourdette.com"]=>
        int(0)
      }
    }
  }
}

From what you describe, it seems you get a different response from the server at some point?

I have no idea if that address really exists or not, so can't say if this is really working as intended or not...

Hi,

Thanks for your answer. I have found the origin of the problem. In fact your library takes too much time to check some domains.

For some domains (bourdette.com, easycash.fr) the connect part is extremely slow. Those domains response with a first response: 220-XXXXX Then a : 220 YYYY a lot of time later (without the "-")

The problem is that your library waits for the second 220 response and it takes forever to check those domains (many other check tools can check the same domains instantly).

I tried to bypass this 220 wait by detecting "220-" line in the expect() function and sending the HELO just after. It worked. In that case, the checking is complete and takes a 300 ms instead of 10 seconds!

But I have problems checking the result because all messages are shifted (I get the "RCPT TO" response after the "QUIT". Here is the log I get in that case (checking testqkjhfved@easycash.fr):

Connecting to mx3.ovh.net:25 Connected to mx3.ovh.net:25 successfully <<<recv: 220-mx3.ovh.net in10

send>>>: EHLO free.fr <<<recv: 220 mx3.ovh.net in10

send>>>: HELO free.fr <<<recv: 250-in10.mail.ovh.net

<<<recv: 250-SIZE 104850000 Reception 2: 250-SIZE 104850000

<<<recv: 250-STARTTLS Reception 2: 250-STARTTLS

<<<recv: 250-ENHANCEDSTATUSCODES Reception 2: 250-ENHANCEDSTATUSCODES

<<<recv: 250 8BITMIME Reception 2: 250 8BITMIME

send>>>: MAIL FROM:fc1507110134@free.fr <<<recv: 250 in10.mail.ovh.net

send>>>: RCPT TO:testqkjhfved@easycash.fr <<<recv: 250 2.1.0 Ok

send>>>: QUIT <<<recv: 550 5.1.1 testqkjhfved@easycash.fr: Recipient address rejected: User unknown

Closing socket to mx3.ovh.net:25

Cordialement, Fabio Chelly

2017-09-13 16:15 GMT+02:00 zytzagoo notifications@github.com:

This is what I get, tested using:

<?phprequire 'smtp-validate-email.php';$from = 'a-happy-camper@campspot.net'; // for SMTP FROM:<> command$emails = array( 'anything@bourdette.com',);$validator = new SMTP_Validate_Email($emails, $from);$validator->debug = true;$smtp_results = $validator->validate();print "\n";var_dump($smtp_results);

Output:

MX records (bourdette.com): Array ( [smtp.bourdette.com] => 10 [bourdette.com] => 0 )

Connecting to smtp.bourdette.com:25 Connected to smtp.bourdette.com:25 successfully <<<recv: 220-zimbra.bourdette.com ESMTP Postfix

<<<recv: 220 zimbra.bourdette.com ESMTP Postfix

send>>>: EHLO campspot.net <<<recv: 250-zimbra.bourdette.com

<<<recv: 250-PIPELINING

<<<recv: 250-SIZE 30000000

<<<recv: 250-VRFY

<<<recv: 250-ETRN

<<<recv: 250-STARTTLS

<<<recv: 250-ENHANCEDSTATUSCODES

<<<recv: 250-8BITMIME

<<<recv: 250 DSN

send>>>: MAIL FROM:a-happy-camper@campspot.net <<<recv: 250 2.1.0 Ok

send>>>: NOOP <<<recv: 250 2.0.0 Ok

send>>>: NOOP <<<recv: 250 2.0.0 Ok

send>>>: RCPT TO:anything@bourdette.com <<<recv: 550 5.1.1 anything@bourdette.com: Recipient address rejected: bourdette.com

Unexpected response to RCPT TO: 550 5.1.1 anything@bourdette.com: Recipient address rejected: bourdette.com

send>>>: NOOP <<<recv: 250 2.0.0 Ok

send>>>: RSET <<<recv: 250 2.0.0 Ok

send>>>: QUIT <<<recv: 221 2.0.0 Bye

Closing socket to smtp.bourdette.com:25 array(2) { ["anything@bourdette.com"]=> bool(false) ["domains"]=> array(1) { ["bourdette.com"]=> array(2) { ["users"]=> array(1) { [0]=> string(8) "anything" } ["mxs"]=> array(2) { ["smtp.bourdette.com"]=> int(10) ["bourdette.com"]=> int(0) } } } }

From what you describe, it seems you get a different response from the server at some point?

I have no idea if that address really exists or not, so can't say if this is really working as intended or not...

— You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub https://github.com/zytzagoo/smtp-validate-email/issues/23#issuecomment-329181530, or mute the thread https://github.com/notifications/unsubscribe-auth/AD32UfXFzfPIyFbrGUlhd1z8QVkWpv5Vks5sh-OMgaJpZM4PUxJs .

There's a delay when checking bourdette.com, but only on what appears to be the first connection from a certain ip (subsequent tests/connections from the same ip [if the ip is "healthy"] are almost instant).

This, to me, looks like it's intentional behavior from the server operators. Or the server might be temporarily overloaded or something? (highly doubt it, but still possible).

Here's another log output from my side, with timestamps:

[2017-10-04T10:20:51.496480+0000] MX records (bourdette.com): Array
(
    [smtp.bourdette.com] => 10
    [bourdette.com] => 0
)

[2017-10-04T10:20:51.496630+0000] Connecting to smtp.bourdette.com:25
[2017-10-04T10:20:51.552752+0000] Connected to smtp.bourdette.com:25 successfully
[2017-10-04T10:20:51.604996+0000] <<<recv: 220 zimbra.bourdette.com ESMTP Postfix

[2017-10-04T10:20:51.605342+0000] send>>>: EHLO campspot.net
[2017-10-04T10:20:51.657142+0000] <<<recv: 250-zimbra.bourdette.com

[2017-10-04T10:20:51.657272+0000] <<<recv: 250-PIPELINING

[2017-10-04T10:20:51.657330+0000] <<<recv: 250-SIZE 30000000

[2017-10-04T10:20:51.657382+0000] <<<recv: 250-VRFY

[2017-10-04T10:20:51.657436+0000] <<<recv: 250-ETRN

[2017-10-04T10:20:51.657487+0000] <<<recv: 250-STARTTLS

[2017-10-04T10:20:51.657540+0000] <<<recv: 250-ENHANCEDSTATUSCODES

[2017-10-04T10:20:51.657593+0000] <<<recv: 250-8BITMIME

[2017-10-04T10:20:51.657645+0000] <<<recv: 250 DSN

[2017-10-04T10:20:51.657709+0000] send>>>: MAIL FROM:<a-happy-camper@campspot.net>
[2017-10-04T10:20:51.710578+0000] <<<recv: 250 2.1.0 Ok

[2017-10-04T10:20:51.710691+0000] send>>>: NOOP
[2017-10-04T10:20:51.761789+0000] <<<recv: 250 2.0.0 Ok

[2017-10-04T10:20:51.761907+0000] send>>>: NOOP
[2017-10-04T10:20:51.811042+0000] <<<recv: 250 2.0.0 Ok

[2017-10-04T10:20:51.811178+0000] send>>>: RCPT TO:<anything@bourdette.com>
[2017-10-04T10:20:51.870558+0000] <<<recv: 550 5.1.1 <anything@bourdette.com>: Recipient address rejected: bourdette.com

[2017-10-04T10:20:51.870693+0000] Unexpected response to RCPT TO: 550 5.1.1 <anything@bourdette.com>: Recipient address rejected: bourdette.com

[2017-10-04T10:20:51.870750+0000] send>>>: NOOP
[2017-10-04T10:20:51.919670+0000] <<<recv: 250 2.0.0 Ok

[2017-10-04T10:20:51.919815+0000] send>>>: RSET
[2017-10-04T10:20:51.969110+0000] <<<recv: 250 2.0.0 Ok

[2017-10-04T10:20:51.969273+0000] send>>>: QUIT
[2017-10-04T10:20:52.020302+0000] <<<recv: 221 2.0.0 Bye

[2017-10-04T10:20:52.020414+0000] Closing socket to smtp.bourdette.com:25
array(2) {
  ["anything@bourdette.com"]=>
  bool(false)
  ["domains"]=>
  array(1) {
    ["bourdette.com"]=>
    array(2) {
      ["users"]=>
      array(1) {
        [0]=>
        string(8) "anything"
      }
      ["mxs"]=>
      array(2) {
        ["smtp.bourdette.com"]=>
        int(10)
        ["bourdette.com"]=>
        int(0)
      }
    }
  }
}
[Finished in 1.2s]

Either way, not sure what I can do more here? The library does it's checks according to the RFCs.

The log file you provided with the ovh servers seems perfectly fine, I don't see anything in it about getting RCPT TO after QUIT or similar?

I've added timestamps to the debug log now in 3cab8a3, but you have yet to provide a concrete log that actually demonstrates the issues (and changes you've done). Without those, and without a reproducible test case (which I cannot get, because the first address mentioned seems to work just fine from where I'm testing), I find it hard to justify changing anything else.

Hi,

On my log, you can see that I get the wrong response to each command ; I get a 250 to my RCPT TO (instead of 550) and the 550 is the response to QUIT

send>>>: RCPT TO:testqkjhfved@easycash.fr <<<recv: 250 2.1.0 Ok

send>>>: QUIT <<<recv: 550 5.1.1 testqkjhfved@easycash.fr: Recipient address rejected: User unknown

Here is the modification I made to the expect() function to by-pass the wait after connecting:

protected function expect($codes, $timeout = null, $empty_response_allowed = false) { $is220 = $codes == self::SMTP_CONNECT_SUCCESS;

...

    if ($is220 && substr($line, 0, 4) == '220-') {
        $this->debug('By-passing 220');
    }
    else {
        while (preg_match("/^[0-9]+-/", $line)) {
            $line = $this->recv($timeout);
            $text .= $line;
        }
    }

... }

Cordialement, Fabio Chelly

2017-10-04 12:35 GMT+02:00 zytzagoo notifications@github.com:

There's a delay when checking bourdette.com, but only on what appears to be the first connection from a certain ip (subsequent tests/connections from the same ip [if the ip is "healthy"] are almost instant).

This, to me, looks like it's intentional behavior from the server operators. Or the server might be temporarily overloaded or something? (highly doubt it, but still possible).

Here's another log output from my side, with timestamps:

[2017-10-04T10:20:51.496480+0000] MX records (bourdette.com): Array ( [smtp.bourdette.com] => 10 [bourdette.com] => 0 )

[2017-10-04T10:20:51.496630+0000] Connecting to smtp.bourdette.com:25 [2017-10-04T10:20:51.552752+0000] Connected to smtp.bourdette.com:25 successfully [2017-10-04T10:20:51.604996+0000] <<<recv: 220 zimbra.bourdette.com ESMTP Postfix

[2017-10-04T10:20:51.605342+0000] send>>>: EHLO campspot.net [2017-10-04T10:20:51.657142+0000] <<<recv: 250-zimbra.bourdette.com

[2017-10-04T10:20:51.657272+0000] <<<recv: 250-PIPELINING

[2017-10-04T10:20:51.657330+0000] <<<recv: 250-SIZE 30000000

[2017-10-04T10:20:51.657382+0000] <<<recv: 250-VRFY

[2017-10-04T10:20:51.657436+0000] <<<recv: 250-ETRN

[2017-10-04T10:20:51.657487+0000] <<<recv: 250-STARTTLS

[2017-10-04T10:20:51.657540+0000] <<<recv: 250-ENHANCEDSTATUSCODES

[2017-10-04T10:20:51.657593+0000] <<<recv: 250-8BITMIME

[2017-10-04T10:20:51.657645+0000] <<<recv: 250 DSN

[2017-10-04T10:20:51.657709+0000] send>>>: MAIL FROM:a-happy-camper@campspot.net [2017-10-04T10:20:51.710578+0000] <<<recv: 250 2.1.0 Ok

[2017-10-04T10:20:51.710691+0000] send>>>: NOOP [2017-10-04T10:20:51.761789+0000] <<<recv: 250 2.0.0 Ok

[2017-10-04T10:20:51.761907+0000] send>>>: NOOP [2017-10-04T10:20:51.811042+0000] <<<recv: 250 2.0.0 Ok

[2017-10-04T10:20:51.811178+0000] send>>>: RCPT TO:anything@bourdette.com [2017-10-04T10:20:51.870558+0000] <<<recv: 550 5.1.1 anything@bourdette.com: Recipient address rejected: bourdette.com

[2017-10-04T10:20:51.870693+0000] Unexpected response to RCPT TO: 550 5.1.1 anything@bourdette.com: Recipient address rejected: bourdette.com

[2017-10-04T10:20:51.870750+0000] send>>>: NOOP [2017-10-04T10:20:51.919670+0000] <<<recv: 250 2.0.0 Ok

[2017-10-04T10:20:51.919815+0000] send>>>: RSET [2017-10-04T10:20:51.969110+0000] <<<recv: 250 2.0.0 Ok

[2017-10-04T10:20:51.969273+0000] send>>>: QUIT [2017-10-04T10:20:52.020302+0000] <<<recv: 221 2.0.0 Bye

[2017-10-04T10:20:52.020414+0000] Closing socket to smtp.bourdette.com:25 array(2) { ["anything@bourdette.com"]=> bool(false) ["domains"]=> array(1) { ["bourdette.com"]=> array(2) { ["users"]=> array(1) { [0]=> string(8) "anything" } ["mxs"]=> array(2) { ["smtp.bourdette.com"]=> int(10) ["bourdette.com"]=> int(0) } } } } [Finished in 1.2s]

Either way, not sure what I can do more here? The library does it's checks according to the RFCs.

The log file you provided with the ovh servers seems perfectly fine, I don't see anything in it about getting RCPT TO after QUIT or similar?

I've added timestamps to the debug log now in 3cab8a3 https://github.com/zytzagoo/smtp-validate-email/commit/3cab8a35e2596d47465c07e52cddde8c6bdcbb63, but you have yet to provide a concrete log that actually demonstrates the issues (and changes you've done). Without those, and without a reproducible test case (which I cannot get, because the first address mentioned seems to work just fine from where I'm testing), I find it hard to justify changing anything else.

— You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub https://github.com/zytzagoo/smtp-validate-email/issues/23#issuecomment-334116005, or mute the thread https://github.com/notifications/unsubscribe-auth/AD32URS7OgzQOyjteOsE4LNE8k_Yt94Sks5so1-GgaJpZM4PUxJs .

I have found the real problem. As soon as the catchall check, is enabled every check to @ easycheck.fr takes 30 seconds instead of 6 seconds normally:

6 seconds are wasted between the connect and the HELO
24 seconds are wasted after the QUIT command (I don't know why: the QUIT works fine if I don't check the catchall).

Cordialement, Fabio Chelly

2017-10-04 14:04 GMT+02:00 Fabio Chelly fabio@chelly.net:

Hi,

On my log, you can see that I get the wrong response to each command ; I get a 250 to my RCPT TO (instead of 550) and the 550 is the response to QUIT

send>>>: RCPT TO:testqkjhfved@easycash.fr <<<recv: 250 2.1.0 Ok

send>>>: QUIT <<<recv: 550 5.1.1 testqkjhfved@easycash.fr: Recipient address rejected: User unknown

Here is the modification I made to the expect() function to by-pass the wait after connecting:

protected function expect($codes, $timeout = null, $empty_response_allowed = false) { $is220 = $codes == self::SMTP_CONNECT_SUCCESS;

...
    if ($is220 && substr($line, 0, 4) == '220-') {
        $this->debug('By-passing 220');
    }
    else {
        while (preg_match("/^[0-9]+-/", $line)) {
            $line = $this->recv($timeout);
            $text .= $line;
        }
    }
... }

Cordialement, Fabio Chelly

2017-10-04 12:35 GMT+02:00 zytzagoo notifications@github.com:

There's a delay when checking bourdette.com, but only on what appears to be the first connection from a certain ip (subsequent tests/connections from the same ip [if the ip is "healthy"] are almost instant).

This, to me, looks like it's intentional behavior from the server operators. Or the server might be temporarily overloaded or something? (highly doubt it, but still possible).

Here's another log output from my side, with timestamps:

[2017-10-04T10:20:51.496480+0000] MX records (bourdette.com): Array ( [smtp.bourdette.com] => 10 [bourdette.com] => 0 )

[2017-10-04T10:20:51.496630+0000] Connecting to smtp.bourdette.com:25 [2017-10-04T10:20:51.552752+0000] Connected to smtp.bourdette.com:25 successfully [2017-10-04T10:20:51.604996+0000] <<<recv: 220 zimbra.bourdette.com ESMTP Postfix

[2017-10-04T10:20:51.605342+0000] send>>>: EHLO campspot.net [2017-10-04T10:20:51.657142+0000] <<<recv: 250-zimbra.bourdette.com

[2017-10-04T10:20:51.657272+0000] <<<recv: 250-PIPELINING

[2017-10-04T10:20:51.657330+0000] <<<recv: 250-SIZE 30000000

[2017-10-04T10:20:51.657382+0000] <<<recv: 250-VRFY

[2017-10-04T10:20:51.657436+0000] <<<recv: 250-ETRN

[2017-10-04T10:20:51.657487+0000] <<<recv: 250-STARTTLS

[2017-10-04T10:20:51.657540+0000] <<<recv: 250-ENHANCEDSTATUSCODES

[2017-10-04T10:20:51.657593+0000] <<<recv: 250-8BITMIME

[2017-10-04T10:20:51.657645+0000] <<<recv: 250 DSN

[2017-10-04T10:20:51.657709+0000] send>>>: MAIL FROM:a-happy-camper@campspot.net [2017-10-04T10:20:51.710578+0000] <<<recv: 250 2.1.0 Ok

[2017-10-04T10:20:51.710691+0000] send>>>: NOOP [2017-10-04T10:20:51.761789+0000] <<<recv: 250 2.0.0 Ok

[2017-10-04T10:20:51.761907+0000] send>>>: NOOP [2017-10-04T10:20:51.811042+0000] <<<recv: 250 2.0.0 Ok

[2017-10-04T10:20:51.811178+0000] send>>>: RCPT TO:anything@bourdette.com [2017-10-04T10:20:51.870558+0000] <<<recv: 550 5.1.1 anything@bourdette.com: Recipient address rejected: bourdette.com

[2017-10-04T10:20:51.870693+0000] Unexpected response to RCPT TO: 550 5.1.1 anything@bourdette.com: Recipient address rejected: bourdette.com

[2017-10-04T10:20:51.870750+0000] send>>>: NOOP [2017-10-04T10:20:51.919670+0000] <<<recv: 250 2.0.0 Ok

[2017-10-04T10:20:51.919815+0000] send>>>: RSET [2017-10-04T10:20:51.969110+0000] <<<recv: 250 2.0.0 Ok

[2017-10-04T10:20:51.969273+0000] send>>>: QUIT [2017-10-04T10:20:52.020302+0000] <<<recv: 221 2.0.0 Bye

[2017-10-04T10:20:52.020414+0000] Closing socket to smtp.bourdette.com:25 array(2) { ["anything@bourdette.com"]=> bool(false) ["domains"]=> array(1) { ["bourdette.com"]=> array(2) { ["users"]=> array(1) { [0]=> string(8) "anything" } ["mxs"]=> array(2) { ["smtp.bourdette.com"]=> int(10) ["bourdette.com"]=> int(0) } } } } [Finished in 1.2s]

Either way, not sure what I can do more here? The library does it's checks according to the RFCs.

The log file you provided with the ovh servers seems perfectly fine, I don't see anything in it about getting RCPT TO after QUIT or similar?

I've added timestamps to the debug log now in 3cab8a3 https://github.com/zytzagoo/smtp-validate-email/commit/3cab8a35e2596d47465c07e52cddde8c6bdcbb63, but you have yet to provide a concrete log that actually demonstrates the issues (and changes you've done). Without those, and without a reproducible test case (which I cannot get, because the first address mentioned seems to work just fine from where I'm testing), I find it hard to justify changing anything else.

— You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub https://github.com/zytzagoo/smtp-validate-email/issues/23#issuecomment-334116005, or mute the thread https://github.com/notifications/unsubscribe-auth/AD32URS7OgzQOyjteOsE4LNE8k_Yt94Sks5so1-GgaJpZM4PUxJs .

easycheck.fr (ovh.net really) is doing various things to prevent bulk validations, including sender address validation etc.

they maybe don't do so much when you come for a reputable ip and/or authenticate before issuing RCPT TO -- don't have time to test that now, there's some more (somewhat related) info here: https://github.com/zytzagoo/smtp-validate-email/issues/3

I don't notice the timings you mention when testing something@easycash.fr from my shitty residential broadband at home, here's a log:

[2017-10-04T18:39:29.470666+0000] MX records (easycash.fr): Array
(
    [mx3.ovh.net] => 1
    [mx4.ovh.net] => 5
    [mxb.ovh.net] => 100
    [easycash.fr] => 0
)

[2017-10-04T18:39:29.476489+0000] Connecting to mx3.ovh.net:25
[2017-10-04T18:39:29.549388+0000] Connected to mx3.ovh.net:25 successfully
[2017-10-04T18:39:29.574901+0000] <<<recv: 220-mx3.ovh.net in12

[2017-10-04T18:39:35.899551+0000] <<<recv: 220 mx3.ovh.net in12

[2017-10-04T18:39:35.902294+0000] send>>>: EHLO campspot.net
[2017-10-04T18:39:35.931512+0000] <<<recv: 250-in12.mail.ovh.net

[2017-10-04T18:39:35.933191+0000] <<<recv: 250-SIZE 104850000

[2017-10-04T18:39:35.937472+0000] <<<recv: 250-STARTTLS

[2017-10-04T18:39:35.938440+0000] <<<recv: 250-ENHANCEDSTATUSCODES

[2017-10-04T18:39:35.939575+0000] <<<recv: 250 8BITMIME

[2017-10-04T18:39:35.940105+0000] send>>>: MAIL FROM:<a-happy-camper@campspot.net>
[2017-10-04T18:39:35.971322+0000] <<<recv: 250 2.1.0 Ok

[2017-10-04T18:39:35.973454+0000] send>>>: NOOP
[2017-10-04T18:39:36.001407+0000] <<<recv: 250 2.0.0 Ok

[2017-10-04T18:39:36.003403+0000] send>>>: NOOP
[2017-10-04T18:39:36.031642+0000] <<<recv: 250 2.0.0 Ok

[2017-10-04T18:39:36.035570+0000] send>>>: RCPT TO:<something@easycash.fr>
[2017-10-04T18:40:26.359878+0000] <<<recv: 450 4.1.8 <a-happy-camper@campspot.net>: Sender address rejected: Domain not found

[2017-10-04T18:40:26.361597+0000] send>>>: NOOP
[2017-10-04T18:40:26.389449+0000] <<<recv: 250 2.0.0 Ok

[2017-10-04T18:40:26.390917+0000] send>>>: RSET
[2017-10-04T18:40:26.418883+0000] <<<recv: 250 2.0.0 Ok

[2017-10-04T18:40:26.420075+0000] send>>>: QUIT
[2017-10-04T18:40:26.449634+0000] <<<recv: 221 2.0.0 Bye

[2017-10-04T18:40:26.451707+0000] Closing socket to mx3.ovh.net:25
array(2) {
  ["something@easycash.fr"]=>
  bool(true)
  ["domains"]=>
  array(1) {
    ["easycash.fr"]=>
    array(2) {
      ["users"]=>
      array(1) {
        [0]=>
        string(9) "something"
      }
      ["mxs"]=>
      array(4) {
        ["mx3.ovh.net"]=>
        int(1)
        ["mx4.ovh.net"]=>
        int(5)
        ["mxb.ovh.net"]=>
        int(100)
        ["easycash.fr"]=>
        int(0)
      }
    }
  }
}

The above (probably non-existing) address turning out to be "valid" is due to public $graylisted_considered_valid = true, and the 450 response code being considered as a "graylist" response code.

From here, this all looks like various symptoms of the same disease -- you're being throttled (for whatever reason). If someone else has some other insights and/or similar experiences, do share.

zytzagoo / smtp-validate-email

Problem with a domain that seem to respond correctly #23