CentOS 6 (dedicated server)
SELinux disabled, and I can't find anything related in IPTABLES
cURL v.17.9.7
Summary: I can not use cURL (shell or PHP) to connect to this particular remote IP address from my server. Domain addresses and other IP addresses are fine, and I have no trouble connecting to the same problem IP address:port using any other method (ping, browsers, other cURL service, other networks, etc.)
For example:
curl http://www.google.com = fine
curl http://234.234.234.234:8888 (my own other server) = fine
curl http://123.456.234.234:8080 (the problem IP address) = "couldn't connect to host"
ping 123.456.234.234 = fine
Looking for: Anything more that I can look at to resolve this
Details (Suspicious Variation at the end):
My test shell command is:
curl http://123.456.234.234:8080
I use a real IP address with a print server running on it in a remote location.
Executing that command from my server shows:
* About to connect() to 123.456.234.234 port 8080 (#0)
* Trying 123.456.234.234...
and it never completes.
Executing essentially the same simple command from PHP (5.2 ... yeah, I know) using cURL:
$ch=curl_init();
curl_setopt($ch,CURLOPT_URL,"http://123.456.234.234:8080/");
curl_exec($ch);
times out with a "couldn't connect to host" cURL connection curl_error.
Executing the shell command from my home linux box pulls up the print server's page, immediately.
Executing the shell command from onlinecurl.com pulls up the print server's page, immediately.
Using any web browser to go to 123.456.234.234:8080 pulls up the print server's page, immediately.
On my server, connecting to a domain URL using cURL is no problem.
It seems to be having an issue only with IP addresses ... not ruling out ONLY this IP address, but it's all I have to work with.
I have tried:
My Server:
1) SELinux: installed, but disabled, therefore "setsebool -P httpd_can_network_connect on" does not execute.
2) IPTABLES: Did not find anything related to that IP address or that port in any of the tables.
3) /etc/hosts : set up "123.456.234.234 ppp.primarydomainonserver.com", and I can use either one, but no connection. I can ping the fake domain from that machine, and PHP cURL makes the translation, too ... but no cURL connect, either way.
4) Went through EVERY cPanel setting provided by the hosting company (not really a cPanel guy)
PHP cURL:
$httpheader = array(
"Host: ppp.primarydomainonserver.com"
);
curl_setopt($ch,CURLOPT_URL,"http://123.456.234.234:8080/");
curl_setopt($ch,CURLOPT_HEADER,1); (and false)
curl_setopt($ch,CURLOPT_HTTPHEADER,$httpheader);
curl_setopt($ch,CURLOPT_RETURNTRANSFER,1);
and using or not using any and all of those.
Note that cURL v.17.9.7 does NOT include RESOLVE, but there doesn't seem to be a problem with that, if you look at the output of the shell test, above and nmap, below ... cURL's got the IP address, it just can't connect to the host.
Print Server: Windows 10, RocketShipIt Thermal Print Server
1) Windows Firewall: server is allowed (I can connect from anywhere) and my server does not match any firewall rule.
2) Windows Security: server is allowed with no restrictions, Private and Public networks
The routers where the print server is located have no firewalls or other control software.
Suspicious Variant:
nmap for a known-good, available HTTP server:port comes back:
nmap -p 80 234.234.234.234
Nmap scan report for www.realwebserver.com (234.234.234.234)
Host is up (0.032s latency).
PORT STATE SERVICE
80/tcp open http
nmap for this problem IP address:port comes back:
nmap -p 8080 123.456.234.234
Nmap scan report for ppp.primarydomainonserver.com (123.456.234.234)
Host is up (0.045s latency).
PORT STATE SERVICE
8080/tcp filtered http-proxy
Could this be affecting the installation of cURL on my server? It doesn't seem to have any affect on any other method I tested to connect.
Finale: I am seeking ANY thoughts on ANY systems/processes/etc. that might be affecting connection from that one server to that one IP address.
Thanks, in advance.
