[php] CURL ERROR: Recv failure: Connection reset by peer - PHP Curl

I'm having this strange error, CURL ERROR: Recv failure: Connection reset by peer

This is how it happens, if I did not connect to the server and all of a sudden trying to connect to the server via CURL in PHP I get the error. When I run the CURL script again the error disappears and then works well the whole time, if I leave the remote server idle for about 30mins or reboot the remote server and try to connect again, I get the error again. So it seems like the connection is idle and then all of sudden the server wakes up and then works and then sleeps again.

This is how my CURL script looks.

$url = Yii::app()->params['pdfUrl'];
            $body = 'title='.urlencode($title).'&client_url='.Yii::app()->params['pdfClientURL'].'&client_id='.Yii::app()->params['pdfClientID'].'&content='.urlencode(htmlentities($content));

            $c = curl_init ($url);
            $body = array(
                "client_url"=>Yii::app()->params['pdfClientURL'],
                "client_id"=>Yii::app()->params['pdfClientID'],
                "title"=>urlencode($title),
                "content"=>urlencode($content)

            );
            foreach($body as $key=>$value) { $body_str .= $key.'='.$value.'&'; }
                rtrim($body_str,'&');

            curl_setopt ($c, CURLOPT_POST, true);
            curl_setopt ($c, CURLOPT_POSTFIELDS, $body_str);
            curl_setopt ($c, CURLOPT_RETURNTRANSFER, true);
            curl_setopt ($c, CURLOPT_CONNECTTIMEOUT , 0);
            curl_setopt ($c, CURLOPT_TIMEOUT  , 20);

            $pdf = curl_exec ($c);
            $errorCode = curl_getinfo($c, CURLINFO_HTTP_CODE);
            $curlInfo = curl_getinfo($c);
            $curlError = curl_error($c);

            curl_close ($c);

I'm totally out of ideas and solutions, please help, I'll appreciate it!!!

If I verbose the output to see what happens using

curl_setopt ($c, CURLOPT_VERBOSE, TRUE);
curl_setopt($c, CURLOPT_STDERR, $fp); 

I get the following

* About to connect() to 196.41.139.168 port 80 (#0)
*   Trying 196.x.x.x... * connected
* Connected to 196.x.x.x (196.x.x.x) port 80 (#0)
> POST /serve/?r=pdf/generatePdf HTTP/1.1
Host: 196.x.x.x
Accept: */*
Content-Length: 7115
Content-Type: application/x-www-form-urlencoded
Expect: 100-continue

* Recv failure: Connection reset by peer
* Closing connection #0
012 20:23:49 GMT
< Server: Apache/2.2.15 (CentOS)
< X-Powered-By: PHP/5.3.3
< Connection: close
< Transfer-Encoding: chunked
< Content-Type: text/html; charset=UTF-8
< 
* Closing connection #0

I've added in the following toe remove the default header and still no luck:

curl_setopt ($c, CURLOPT_HTTPHEADER, array( 'Expect:' ) );

> Accept: */* Content-Length: 8414 Content-Type:
> application/x-www-form-urlencoded
> 
> * Recv failure: Connection reset by peer
> * Closing connection #0 r: Apache/2.2.15 (CentOS) < X-Powered-By: PHP/5.3.3 < Connection: close < Transfer-Encoding: chunked <
> Content-Type: text/html; charset=UTF-8 < 
> * Closing connection #0

This question is related to php curl yii

The answer is


I faced same error but in a different way.

When you curl a page with a specific SSL protocol.

curl --sslv3 https://example.com

If --sslv3 is not supported by the target server then the error will be

curl: (35) TCP connection reset by peer

With the supported protocol, error will be gone.

curl --tlsv1.2 https://example.com

So what is the URL that Yii::app()->params['pdfUrl'] gives? You say it should be https, but the log shows it's connecting on port 80... which almost no server is setup to accept https connections on. cURL is smart enough to know https should be on port 443... which would suggest that your URL has something wonky in it like: https://196.41.139.168:80/serve/?r=pdf/generatePdf

That's going to cause the connection to be terminated, when the Apache at the other end cannot do https communication with you on that port.

You realize your first $body definition gets replaced when you set $body to an array two lines later? {Probably just an artifact of you trying to solve the problem} You're also not encoding the client_url and client_id values (the former quite possibly containing characters that need escaping!) Oh and you're appending to $body_str without first initializing it.

From your verbose output we can see cURL is adding a content-length header, but... is it correct? I can see some comments out on the internets of that number being wrong (especially with older versions)... if that number was to small (for example) you'd get a connection-reset before all the data is sent. You can manually insert the header:

curl_setopt ($c, CURLOPT_HTTPHEADER, 
   array("Content-Length: ". strlen($body_str))); 

Oh and there's a handy function http_build_query that'll convert an array of name/value pairs into a URL encoded string for you.

All this rolls up into the final code:

$post=http_build_query(array(
  "client_url"=>Yii::app()->params['pdfClientURL'],
  "client_id"=>Yii::app()->params['pdfClientID'],
  "title"=>$title,
  "content"=>$content));

//Open to URL
$c=curl_init(Yii::app()->params['pdfUrl']);
//Send post
curl_setopt ($c, CURLOPT_POST, true);
//Optional: [try with/without]
curl_setopt ($c, CURLOPT_HTTPHEADER, array("Content-Length: ".strlen($post))); 
curl_setopt ($c, CURLOPT_POSTFIELDS, $post);
curl_setopt ($c, CURLOPT_RETURNTRANSFER, true);
curl_setopt ($c, CURLOPT_CONNECTTIMEOUT , 0);
curl_setopt ($c, CURLOPT_TIMEOUT  , 20);
//Collect result
$pdf = curl_exec ($c);
$curlInfo = curl_getinfo($c);
curl_close($c);

Normally this error means that a connection was established with a server but that connection was closed by the remote server. This could be due to a slow server, a problem with the remote server, a network problem, or (maybe) some kind of security error with data being sent to the remote server but I find that unlikely.

Normally a network error will resolve itself given a bit of time, but it sounds like you’ve already given it a bit of time.

cURL sometimes having issue with SSL and SSL certificates. I think that your Apache and/or PHP was compiled with a recent version of the cURL and cURL SSL libraries plus I don't think that OpenSSL was installed in your web server.

Although I can not be certain However, I believe cURL has historically been flakey with SSL certificates, whereas, Open SSL does not.

Anyways, try installing Open SSL on the server and try again and that should help you get rid of this error.


This is a firewall issue, if you are using a VMware application, make sure the firewall on the antivirus is turned off or allowing connections.

If this server is on a secure network, please have a look at firewall rules of the server.

Thanks Ganesh PNS


We had the same issue, in making a websocket connection to the Load Balancer. The issue is in LB, accepting http connection on port 80 and forwarding the request to node (tomcat app on port 8080). We have changed this to accept tcp (http has been changed as 'tcp') connection on port 80. So the first handshake request is forwarded to Node and a websocket connection is made successfully on some random( as far as i know, may be wrong) port.

below command has been used to test the websocket handshake process.

curl -v -i -N -H "Connection: Upgrade" -H "Upgrade: websocket" -H "Host: localhost" -H "Origin: http://LB URL:80" http://LB URL

  • Rebuilt URL to: http:LB URL/
  • Trying LB URL...
  • TCP_NODELAY set
  • Connected to LB URL (LB URL) port 80 (#0)

    GET / HTTP/1.1 Host: localhost User-Agent: curl/7.60.0 Accept: / Connection: Upgrade Upgrade: websocket Origin: http://LB URL:80

  • Recv failure: Connection reset by peer
  • Closing connection 0 curl: (56) Recv failure: Connection reset by peer

In my case there was problem in URL. I've use https://example.com - but they ensure 'www.' - so when i switched to https://www.example.com everything was ok. The proper header was sent 'Host: www.example.com'.

You can try make a request in firefox brwoser, persist it and copy as cURL - that how I've found it.


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