PHP cURL无法解析api.mailjet.com：浏览器失效终端正常求助

在PHP中遇到持续性cURL问题：通过浏览器运行PHP脚本发起cURL请求时，报错“cURL Error: Could not resolve host: api.mailjet.com”，但终端执行相同cURL命令完全正常。

已排查步骤 #

• 验证php.ini配置：
  • 已启用extension=curl；
  • 通过phpinfo()页面确认cURL已启用。
• 检查文件权限与路径：
  • 为/var/www/htdocs及其子目录设置755权限；
  • 验证PHP脚本中的路径正确。
• 调试DNS解析与网络连通性：
  • 脚本中添加调试信息，错误输出：

    Resolved IP for api.mailjet.com: api.mailjet.com - DNS resolution failed.
    cURL Error: Could not resolve host: api.mailjet.com
    

  • 调试脚本代码：

    <?php
    error_reporting(E_ALL);
    ini_set('display_errors', 1);
    chdir('/var/www/htdocs');
    $ip = gethostbyname('api.mailjet.com');
    echo "Resolved IP for api.mailjet.com: $ip<br>";
    require 'vendor/autoload.php';
    use \Mailjet\Resources;
    $mj = new \Mailjet\Client('your-api-key', 'your-secret-key', true, ['version' => 'v3.1']);
    $body = [ /*...*/ ];
    $response = $mj->post(Resources::$Email, ['body' => $body]);
    if ($response->success()) { echo "Email sent successfully!"; } else { echo "Failed to send email."; var_dump($response->getData()); }
    ?>
    

  • 终端通过nslookup和curl确认DNS解析正常：

    $ nslookup api.mailjet.com
    Server:         108.61.10.10
    Address:        108.61.10.10#53
    Non-authoritative answer:
    Name:   api.mailjet.com
    Address: 35.187.79.8
    
    $ curl -v https://api.mailjet.com/v3.1/send
    * Host api.mailjet.com:443 was resolved.
    * IPv6: (none)
    * IPv4: 35.187.79.8
    *   Trying 35.187.79.8:443...
    * Connected to api.mailjet.com (35.187.79.8) port 443
    ...
    Not authorized
    

• 验证防火墙与网络配置：
  • 执行命令检查防火墙规则：

    $ doas pfctl -sr | grep block
    block drop all
    

• 重启网络服务：

  $ sudo sh /etc/netstart
  

环境信息 #

• OS: OpenBSD
• PHP Version: 8.2
• Web Server: Apache

DNS配置 #

nameserver 108.61.10.10
nameserver 9.9.9.9
nameserver 2001:19f0:300:1704::6
nameserver 2620:fe::fe

浏览器完整错误信息 #

Fatal error: Uncaught GuzzleHttp\Exception\ConnectException: cURL error 6: Could not resolve host: api.mailjet.com for https://api.mailjet.com/v3.1/send in /htdocs/vendor/guzzlehttp/guzzle/src/Handler/CurlFactory.php:210 
Stack trace:
 #0 /htdocs/vendor/guzzlehttp/guzzle/src/Handler/CurlFactory.php(158): GuzzleHttp\Handler\CurlFactory::createRejection()
 #1 /htdocs/vendor/guzzlehttp/guzzle/src/Handler/CurlFactory.php(110): GuzzleHttp\Handler\CurlFactory::finishError()
 #2 /htdocs/vendor/guzzlehttp/guzzle/src/Handler/CurlHandler.php(47): GuzzleHttp\Handler\CurlFactory::finish()
 #3 /htdocs/vendor/guzzlehttp/guzzle/src/Handler/Proxy.php(28): GuzzleHttp\Handler\CurlHandler->__invoke()
 #4 /htdocs/vendor/guzzlehttp/guzzle/src/Handler/Proxy.php(48): GuzzleHttp\Handler\Proxy::GuzzleHttp\Handler\{closure}()
 #5 /htdocs/vendor/guzzlehttp/guzzle/src/PrepareBodyMiddleware.php(64): GuzzleHttp\Handler\Proxy::GuzzleHttp\Handler\{closure}()
 #6 /htdocs/vendor/guzzlehttp/guzzle/src/Middleware.php(31): GuzzleHttp\PrepareBodyMiddleware->__invoke()
 #7 /htdocs/vendor/guzzlehttp/guzzle/src/RedirectMiddleware.php(71): GuzzleHttp\Middleware::GuzzleHttp\{closure}()
 #8 /htdocs/vendor/guzzlehttp/guzzle/src/Middleware.php(66): GuzzleHttp\RedirectMiddleware->__invoke()
 #9 /htdocs/vendor/guzzlehttp/guzzle/src/HandlerStack.php(75): GuzzleHttp\Middleware::GuzzleHttp\{closure}()
 #10 /htdocs/vendor/guzzlehttp/guzzle/src/Client.php(333): GuzzleHttp\HandlerStack->__invoke()
 #11 /htdocs/vendor/guzzlehttp/guzzle/src/Client.php(169): GuzzleHttp\Client->transfer()
 #12 /htdocs/vendor/guzzlehttp/guzzle/src/Client.php(189): GuzzleHttp\Client->requestAsync()
 #13 /htdocs/vendor/mailjet/mailjet-apiv3-php/src/Mailjet/Request.php(238): GuzzleHttp\Client->request()
 #14 /htdocs/vendor/guzzlehttp/guzzle/src/ClientTrait.php(95): Mailjet\Request->request()
 #15 [internal function]: Mailjet\Request->post()
 #16 /htdocs/vendor/mailjet/mailjet-apiv3-php/src/Mailjet/Request.php(140): call_user_func()
 #17 /htdocs/vendor/mailjet/mailjet-apiv3-php/src/Mailjet/Client.php(342): Mailjet\Request->call()
 #18 /htdocs/vendor/mailjet/mailjet-apiv3-php/src/Mailjet/Client.php(99): Mailjet\Client->_call()
 #19 /htdocs/test-mailjet.php(31): Mailjet\Client->post()
 #20 {main} thrown in /htdocs/vendor/guzzlehttp/guzzle/src/Handler/CurlFactory.php on line 210

希望得到关于浏览器中cURL请求失败但终端正常的原因分析。

内容的提问来源于stack exchange，提问作者Tyler Morales