how to use SMTP server on a proxy network

I have searched a lot can't do anything. i am on a proxy network and using arduino uno to send mails but it is not connecting to the internet. I have seen a example of connecting to proxy network but that works for HTTP request only can't use the same method to connect to the smtpcorp.com port 2525. Please help me out and tell me where i have to make changes.

#include <SPI.h>;
#include <Ethernet.h>;

// Arduino network information
byte mac[] = { 0x00, 0xAA, 0xBB, 0xCC, 0xDE, 0x02 };
EthernetClient client;
char smtpServer[] = "smtpcorp.com";
void setup()
{
Serial.begin(9600); // for debug mode
setupComm();
}
void loop()
{
email("hello");
delay(1000);
}
// ethernet shield connection init
void setupComm()
{
Serial.println("Trying to connect");
if (!Ethernet.begin(mac)){
Serial.println("Failed to DHCP");
// verifyng connection
while(true);
}
delay(10000);
// IP address is:
Serial.print("IP address: ");
for (byte thisByte = 0; thisByte < 4; thisByte++) {
Serial.print(Ethernet.localIP()[thisByte], DEC);
Serial.print(".");
}
Serial.println();
}
// now I send email
bool email(char* text)
{
bool success = false;
Serial.println("Sending email...");
if (client.connect(smtpServer, 2525)){ //2525 is SMTP Server port
Serial.println("connected");
delay(100);
client.println("EHLO arduino");
for(int i=0; i<999; ++i){
if(client.read() > 0)
break;
}
Serial.println("responded");
client.println("AUTH LOGIN"); //see "http://base64-encoder-online.waraxe.us/"
client.println("xxxxxxxxxx"); //Type your username and encode it
client.println("yyyyyyyyyy"); //Type your password and encode it

// Put your "from" email address here
client.println("MAIL FROM:dumm@gmail.com"); //Seems you can write what you want here...
for(int i=0; i<999; ++i){
if(client.read() > 0)
break;
}
client.println("RCPT TO:mail@mail.com");
for(int i=0; i<999; ++i){
if(client.read() > 0)
break;
}
client.println("DATA");
for(int i=0; i<999; ++i){
if(client.read() > 0)
break;
}
//Sender
client.println("from: mail@mail.com"); //Sender address
client.println("to: mail@mail.com"); //Receiver address
client.println("SUBJECT: From your arduino");
client.println("");
client.println(text);
client.println(".");
client.println("QUIT");
for (int i = 0; i<999; ++i){
if(i > 998){
Serial.println("error: No response");
}
if(client.read() > 0)
break;
}
success = true;
client.println();
Serial.println("end");
}
else {
Serial.println("Failed");
client.println("QUIT"); //Disconnection
}
client.stop();
return success;
}

Did you try to connect to the SMTP server from your PC using a telnet client to verify you are giving the correct commands?

I would also print out the server responses so you can see whats happening

Instead of

for(int i=0; i<999; ++i){
      if(client.read() > 0)
        break;
    }

maybe

for(int i=0; i<999; ++i){
      if(client.available() > 0)
        break;
    }
while (client.available()>0) {
  Serial.print(client.read())
}
Serial.println();

(see how nice it is when you use the code tags..)