IP failover in cURL - is it possible? - php

I have VPS on OVH, and I have one failover IP (eth0:0). Could you tell me, if It is possible to use this failover IP in cURL requests with PHP?
I tried:
curl_setopt($ch, CURLOPT_INTERFACE, "eth0:0");
and:
curl_setopt($ch, CURLOPT_INTERFACE, "XX.XXX.XXX.XXX");
..but it doesn't work :-/

Since I can't comment, I will try to help you here.
Can you try the following command and see if you get the correct results?
curl --interface eth0 http://ifconfig.me
curl --interface eth0:0 http://ifconfig.me
Check if the first one returns the correct IP for the device eth0, and the second one the correct IP for the device eth0:0.
The reason I am asking that is to try to figure out if the problem is with curl or on the OS (routing tables, etc).

Related

How to resolve cURL Error (7): couldn't connect to host?

I send an item code to a web service in xml format using cUrl(php). I get the correct response in localhost, but when do it server it shows
cURL Error (7): couldn't connect to host
And here's my code:
function xml_post($post_xml, $url)
{
$user_agent = $_SERVER['HTTP_USER_AGENT'];
$ch = curl_init(); // initialize curl handle
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_FAILONERROR, 1);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
curl_setopt($ch, CURLOPT_TIMEOUT, 50);
curl_setopt($ch, CURLOPT_POSTFIELDS, $post_xml);
curl_setopt($ch, CURLOPT_USERAGENT, $user_agent);
// curl_setopt($ch, CURLOPT_PORT, $port);
$data = curl_exec($ch);
$curl_errno = curl_errno($ch);
$curl_error = curl_error($ch);
if ($curl_errno > 0) {
echo "cURL Error ($curl_errno): $curl_error\n";
} else {
echo "Data received\n";
}
curl_close($ch);
echo $data;
}
I send the item code to the tally and fetch the details from it. I tried using both the versions php 4+ and php5+, nothing works out Any solution.
CURL error code 7 (CURLE_COULDNT_CONNECT)
is very explicit ... it means Failed to connect() to host or proxy.
The following code would work on any system:
$ch = curl_init("http://google.com"); // initialize curl handle
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
$data = curl_exec($ch);
print($data);
If you can not see google page then .. your URL is wrong or you have some firewall or restriction issue.
“CURL ERROR 7 Failed to connect to Permission denied” error is caused, when for any reason curl request is blocked by some firewall or similar thing.
you will face this issue when ever the curl request is not with standard ports.
for example if you do curl to some URL which is on port 1234, you will face this issue where as URL with port 80 will give you results easily.
Most commonly this error has been seen on CentOS and any other OS with ‘SElinux’.
you need to either disable or change ’SElinux’ to permissive
have a look on this one
http://www.akashif.co.uk/php/curl-error-7-failed-to-connect-to-permission-denied
Hope this helps
If you have tried all the ways and failed, try this one command:
setsebool -P httpd_can_network_connect on
In PHP, If your network under proxy. You should set the proxy URL and port
curl_setopt($ch, CURLOPT_PROXY, "http://url.com"); //your proxy url
curl_setopt($ch, CURLOPT_PROXYPORT, "80"); // your proxy port number
This is solves my problem
In my case I had something like cURL Error (7): ... Operation Timed Out. I'm using the network connection of the company I'm working for. I needed to create some environment variables. The next worked for me:
In Linux terminal:
$ export https_proxy=yourProxy:80
$ export http_proxy=yourProxy:80
In windows I created (the same) environment variables in the windows way.
I hope it helps!
Regards!
Are you able to hit that URL by browser or by PHP script? The error shown is that you could not connect. So first confirm that the URL is accessible.
Check if port 80 and 443 are blocked. or enter - IP graph.facebook.com and enter it in etc/hosts file
you can also get this if you are trying to hit the same URL with multiple HTTP request at the same time.Many curl requests wont be able to connect and so return with error
This issue can also be caused by making curl calls to https when it is not configured on the remote device. Calling over http can resolve this problem in these situations, at least until you configure ssl on the remote.
In my case, the problem was caused by the hosting provider I was using blocking http packets addressed to their IP block that originated from within their IP block. Un-frickin-believable!!!
For a couple of days I was totally blocked on this. I'm very very new to networking/vms but was keen to try set it up myself instead of paying a hosting company to do it for me.
Context
I'm rebuilding the server side for an app that uses php routines to return various bits of data from internal sources as well as external APIs for a map based app. I have started an Oracle VM instance and have installed/set up Apache and php. All running totally fine, until one of my php routines tries to execute a cURL. I start implementing error logging to find that I don't even get a message - just '7', despite implementation being very similar to the above. My php routine accessing an internal file for data was running successfully so I was fairly sure it wasn't an Apache or php issue. I also checked my Apache error logs, nothing telling.
Solution
I nearly gave up - there's talk on disabling SELinux above and in other articles, I tried that and it did work for my purposes, but here's a really good article on why you shouldn't disable SELinux https://www.electronicdesign.com/technologies/embedded-revolution/article/21807408/dont-do-it-disabling-selinux
If temporarily disabling it works and like me you don't want to do this (but it confirms that SELinux is blocking you!), I found a neat little command that actually prints out any SELinux issues in a more readable fashion:
sealert -a /var/log/audit/audit.log
This returned the following:
found 1 alerts in /var/log/audit/audit.log
--------------------------------------------------------------------------------
SELinux is preventing php-fpm from name_connect access on the tcp_socket port 443.
Great, I now get a bit more information than just '7'. Reading further down, I can see it actually makes suggestions:
***** Plugin catchall_boolean (24.7 confidence) suggests ******************
If you want to allow httpd to can network connect
Then you must tell SELinux about this by enabling the 'httpd_can_network_connect' boolean.
Do
setsebool -P httpd_can_network_connect 1
This has been mentioned further above but now I have a bit more context and an explanation as to what it does. I run the command, and I'm in business. Furthermore, my SELinux is still set to enforcing, meaning my machine is more secure.
There are many other suggestions logged out, if you're blocked it might be worth logging out/checking out /var/log/audit/audit.log.

curl_exec($ch) not executing on external domains anymore, why?

I was using cURL to scrape content from a site and just recently my page stated hanging when it reached curl_exec($ch). After some tests I noticed that it could load any other page from my own domain but when attempting to load from anything external I'll get a connect() timeout! error.
Here's a simplified version of what I was using:
<?php
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL,'http://www.google.com');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 0);
$contents = curl_exec ($ch);
curl_close ($ch);
echo $contents;
?>
Here's some info I have about my host from my phpinfo():
PHP Version 5.3.1
cURL support enabled
cURL Information 7.19.7
Host i686-pc-linux-gnu
I don't have access to SSH or modifying the php.ini file (however I can read it). But is there a way to tell if something was recently set to block cURL access to external domains? Or is there something else I might have missed?
Thanks,
Dave
I'm not aware about any setting like that, it would not make much sense.
As you said you are on a remote webserver without console access I guess that your activity has been detected by the host or more likely it caused issues and so they firewalled you.
A silent iptables DROP would cause this.
When scraping google you need to use proxies for more than a few hand full of requests and you should never abuse your webservers primary IP if it's not your own. That's likely a breach of their TOS and could even result in legal action if they get banned from Google (which can happen).
Take a look at Google rank checker that's a PHP script that does exactly what you want using CURL and proper IP management.
I can't think of anything that's causing a timeout than a firewall on your side.
I'm not sure why you're getting a connect() timeout! error, but the following line:
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 0);
If it's not set to 1, it will not return any of the page's content back into your $contents.

How to identify server IP address in PHP

How can I identify the server IP address in PHP?
Like this for the server ip:
$_SERVER['SERVER_ADDR'];
and this for the port
$_SERVER['SERVER_PORT'];
If you are using PHP version 5.3 or higher you can do the following:
$host= gethostname();
$ip = gethostbyname($host);
This works well when you are running a stand-alone script, not running through the web server.
for example:
$_SERVER['SERVER_ADDR']
when your on IIS, try:
$_SERVER['LOCAL_ADDR']
I came to this page looking for a way of getting my own ip address not the one of the remote machine connecting to me.
This will not work for a windows machine.
But in case someone searches for what I was looking for:
#! /usr/bin/php
<?php
$my_current_ip=exec("ifconfig | grep -Eo 'inet (addr:)?([0-9]*\.){3}[0-9]*' | grep -Eo '([0-9]*\.){3}[0-9]*' | grep -v '127.0.0.1'");
echo $my_current_ip;
(Shamelessly adapted from How to I get the primary IP address of the local machine on Linux and OS X?)
Neither of the most up-voted answers will reliably return the server's public address. Generally $_SERVER['SERVER_ADDR'] will be correct, but if you're accessing the server via a VPN it will likely return the internal network address rather than a public address, and even when not on the same network some configurations will will simply be blank or have some other specified value.
Likewise, there are scenarios where $host= gethostname(); $ip = gethostbyname($host); won't return the correct values because it's relying on on both DNS (either internally configured or external records) and the server's hostname settings to extrapolate the server's IP address. Both of these steps are potentially faulty. For instance, if the hostname of the server is formatted like a domain name (i.e. HOSTNAME=yahoo.com) then (at least on my php5.4/Centos6 setup) gethostbyname will skip straight to finding Yahoo.com's address rather than the local server's.
Furthermore, because gethostbyname falls back on public DNS records a testing server with unpublished or incorrect public DNS records (for instance, you're accessing the server by localhost or IP address, or if you're overriding public DNS using your local hosts file) then you'll get back either no IP address (it will just return the hostname) or even worse it will return the wrong address specified in the public DNS records if one exists or if there's a wildcard for the domain.
Depending on the situation, you can also try a third approach by doing something like this:
$external_ip = exec('curl http://ipecho.net/plain; echo');
This has its own flaws (relies on a specific third-party site, and there could be network settings that route outbound connections through a different host or proxy) and like gethostbyname it can be slow. I'm honestly not sure which approach will be correct most often, but the lesson to take to heart is that specific scenarios/configurations will result in incorrect outputs for all of these approaches... so if possible verify that the approach you're using is returning the values you expect.
This is what you could use as an adaptation of the above examples without worrying about curl installed on your server.
<?php
// create a new cURL resource
$ch = curl_init ();
// set URL and other appropriate options
curl_setopt ($ch, CURLOPT_URL, "http://ipecho.net/plain");
curl_setopt ($ch, CURLOPT_HEADER, 0);
curl_setopt ($ch, CURLOPT_RETURNTRANSFER, true);
// grab URL and pass it to the browser
$ip = curl_exec ($ch);
echo "The public ip for this server is: $ip";
// close cURL resource, and free up system resources
curl_close ($ch);
?>
Check the $_SERVER array
echo $_SERVER['SERVER_ADDR'];
The previous answers all give $_SERVER['SERVER_ADDR']. This will not work on some IIS installations. If you want this to work on IIS, then use the following:
$server_ip = gethostbyname($_SERVER['SERVER_NAME']);
If you are using PHP in bash shell you can use:
$server_name=exec('hostname');
Because $_SERVER[] SERVER_ADDR, HTTP_HOST and SERVER_NAME are not set.
I found this to work for me:
GetHostByName("");
Running XAMPP v1.7.1 on Windows 7 running Apache webserver.
Unfortunately it just give my gateway IP address.
I just created a simple script that will bring back the $_SERVER['REMOTE_ADDR'] and $_SERVER['SERVER_ADDR'] in IIS so you don't have to change every variable. Just paste this text in your php file that is included in every page.
/** IIS IP Check **/
if(!$_SERVER['SERVER_ADDR']){ $_SERVER['SERVER_ADDR'] = $_SERVER['LOCAL_ADDR']; }
if(!$_SERVER['REMOTE_ADDR']){ $_SERVER['REMOTE_ADDR'] = $_SERVER['LOCAL_ADDR']; }
$serverIP = $_SERVER["SERVER_ADDR"];
echo "Server IP is: <b>{$serverIP}</b>";
You may have to use $HTTP_SERVER_VARS['server_ADDR'] if you are not getting anything from above answers and if you are using older version of PHP
You can use https://icanhazip.com and since Cloudflare owned this project sometimes it can be even more reliable.
$my_real_ip = file_get_contents('https://icanhazip.com/');
Check the $_SERVER array
echo $_SERVER['SERVER_ADDR'];
Here is one solution when the site is running behind a load-balancer, a reverse proxy server, or a CDN like CloudFront:
$conn = curl_init();
curl_setopt($conn, CURLOPT_URL, 'any.valid.url');
curl_exec($conn);
$WebServerIP = curl_getinfo($conn)['local_ip'];
To accurately get the external IP address, you can call checkip.amazonaws.com, a service provided by Amazon.
$ip = exec("curl https://checkip.amazonaws.com");
As we can see it's such a widespread problem that AWS has created that very tool for the world to use.
I would use that over other similar services, since it's provided by AWS and will probably be around for long.
Like this:
$_SERVER['SERVER_ADDR'];

Is there a way to check if a host is up?

I'm trying to do this in PHP. I need to check if a specified host is "up"
I thought of pinging the specified host (though I'm not sure how I would, since that would require root. --help here?)
I also though of using fsockopen() to try to connect on a specified port, but that would fail too, if the host wasn't listening for connections on that port.
Additionally, some hosts block ping requests, so how might I get around this? This part isn't a necessity, though, so don't worry about this too much. I realize this one might get tricky.
I typically do a simple cURL for a public page and see if it returns a 200. If you get a 500, 404, or anything besides a 200 response you know something fishy is up.
The short answer is that there is no good, universal way to do this. Ping is about as close as you can get (almost all hosts will respond to that), but as you observed, in PHP that usually requires root access to use the low port.
Does your host allow you to execute system calls, so you could run the ping command at the OS level and then parse the results? This is probably your best bet.
$result = exec("ping -c 2 google.com");
If a host is blocking a ping request, you could do a more general portscan to look for other open ports (but this is pretty rude, don't do it to hosts who haven't given you specific permission). Nmap is a good tool for doing this. It uses quite a few tricks to figure out if a host is up and what services may or may not be running. Be careful though, as some shared hosting providers will terminate your account for "hacking activity" if you install and use Nmap, especially against hosts you do not control or have permission to probe.
Beyond that, if you are on the same unswitched ethernet layer as another host (if you happen to be on the same open WiFi network, for example), an ethernet adaptor in promiscuous mode can sniff traffic to and from a host even if it does not respond directly to you.
You could use cURL
$url = 'yoururl';
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_NOBODY, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
curl_exec($ch);
$retcode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);
if (200==$retcode) {
// All's well
} else {
// not so much
}
For the host to be monitored at all, at least one port must be open. Is the host a web server? If so you could just open a connection to port 80, as long as it's opened successfully then at least some part of the host is working.
A better solution would be to have a script that is web accessible to just your monitor, and then you could open a connection to that, and that script would return various bits of system info.
EDIT--
How thorough do you want this test to be?
[server on] -> [apache running] -> [web application working]
Are all different levels of working. Just showing apache is returning something does at least show the server is on, but not that your web app is running.
(I realise that you may not be running anything like this but I hope it's a useful example)
EDIT--
Would it be worth installing a lightweight http server (I mean very light weight) just for monitoring?
Failing that could you install something on the hosts that phoned home every so often to show they are up?
I used gethostbyname($hostname).
The function gives you the IP if the host is up, or the input hostname if it couldn't find the IP.
if ($hostname !== gethostbyname($hostname)) {
//Host is up
}

PHP curl and file_get_contents returns the main website located on the server when I enter a valid URL without DNS resolution

When I call the following:
file_get_contents('http://whgfdw.ca');
or
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'http://whgfdw.ca');
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_exec($ch);
The return value is the HTML of the homepage of the main site located on the local (dedicated) webserver. I would be grateful if anyone could help me understand this? Perhaps there is something I'm overlooking.
I can't use simple URL validation because http://whgfdw.ca is a perfectly fine URL; it just doesn't have a DNS entry.
My ideal functionality is to be able to catch a DNS lookup failure or a 404 or a case of no content and then act on it. Thanks!
If you got a valid response then that DNS entry exists somewhere. It may be on an internal DNS server, in the /etc/hosts file of the local server or somewhere else in the stack but the bottom line is its being resolved in some way. So the question becomes wheres the entry its resolving to entered. Its possible that there is an application that is set to resolve all lookups to the local server (similar to how openDNS and many ISP's will resolve an un-resolved DNS name to their search page).
Given that its somehow being resolved there really isnt a way to validate it unless you compare the content of the response to some content you expect. Catching a 404 is pretty easy, you can also set up reverse lookup in php to catch unresolved names i believe. But you need to tackle that resolution first i should think.

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