Using Cisco VPN Client Release 4.8.02.0030 for Linux on Centos 5.
Locally I have a C application that accepts socket requests and sends data.
On the remote server farm in the DMZ is a php page that asks the socket on the local machine for data over the socket.
It gets around 1300 bytes out of the 4500 or so bytes and errs out:
function.socket-read</a>]: unable to read from socket [104]: Connection reset by peer
The identical application running on a server inside the remote server farm sends the full 4500 bytes or so of data to the php application.
I also wrote a trivial C client for the application to see if it was a php issue. It works from the local host to the local application, but not from any remote host on the server farm to the local application.
I uploaded the c file, and it is also below.
(EDIT) I also uploaded the php client code (client.php) and pasted it below as well.
The php client gets fewer characters returned, not sure why
Thus it appears that the VPN Client is truncating the data, possibly at the MTU boundary.
The basic issue:
remote host->remote application - OK
remote host->local application (via vpnclient) - Truncates data
Please note that I have tried read and write in addition to send/recv on the socket with identical results.
Any ideas on how to get around this would be appreciated.
The php client code:
<?php
// Create a TCP/IP Socket
$socket = socket_create (AF_INET, SOCK_STREAM, 0);
if ($socket < 0) { echo "socket() failed: reason: " . strerror ($socket) . "\n"; }
// Connect to Target
$result = socket_connect ($socket, $address, $service_port);
if ($result < 0) { echo "connect() failed.\nReason: ($result) " . strerror($result) . "\n"; }
// Send Input Transaction
socket_write ($socket, $outPost, strlen ($outPost));
// Read Output Transaction
//get length of response
$tmp = socket_read ($socket, 6, PHP_NORMAL_READ);
$slen = (int)($tmp-6);
$out = (string)$tmp;
//get response
while(($sting = socket_read($socket, $slen)) !== false) {
$out = $out.$sting;
if(strlen($out) >= $slen) break;
// if(strlen($out) >= ($slen-6)) break;
}
return $out."\n";
// Close Socket
socket_close ($socket);
?>
The c client code:
//file client.c
//simple socket client
#include <sys/socket.h>
#include <netinet/in.h>
...
#define PORTNUMBER 1528
int main(void){
//some declarations
...
struct hostent *hp;
struct sockaddr_in name;
...
//host
sprintf(hostname, "somehostname");
hp = gethostbyname(hostname));
s = socket(AF_INET, SOCK_STREAM, 0);
//Create the address of the server.
memset(&name, 0, sizeof(struct sockaddr_in));
name.sin_family = AF_INET;
name.sin_port = htons(PORTNUMBER);
memcpy(&name.sin_addr, hp->h_addr_list[0], hp->h_length);
len = sizeof(struct sockaddr_in);
connect(s, (struct sockaddr *) &name, len);
//send a request
nbytes = send(s, msg, n, 0); //some request
nflags = 0;
//get the message length
nbytes = recv(s, msgout, 6, nflags);
printf("msg from socket\n%s", msgout);
n = atoi(msgout);
//get the message
nbytes = recv(s, msgout, n, nflags); //nbytes around 4500 bytes
printf("msg from socket\n%s", msgout);
close(s);
exit(0);
}//end main
Edit:
I uploaded the php request - file client.php and pasted it into the text
