Hello there! I am making an SMTP mail client and mail server project of computer networks on a single host (in Ubuntu).

I am having a problem in sending an attachment to the mail server. I am using simple send(socket descriptor, message.txt, sizeof(message), flag) and recv(sockfd, buf, sizeof(buf), flag) to send and recieve mails fto and from mail server.

But I am unable to send an attachment. Please help me to develop a a code that can send attachments to the server and at the server side recieve those attachments.