SMTP error with data command

[blabla32]

Hello :)

I work currently on the program and I need send a mail. I have a problem with a data SMTP command. Indeed, this command return this error message:

503 5.5.0 <DATA>: Data command rejected: Improper use of SMTP command pipelining

This is my source code (just the interesting part ;)):

char data[] = "HELO smtp.yopmail.com\n"
                  "MAIL FROM:<[e-mail]>\n"
                  "RCPT TO:<[e-mail]>\n"
                  "DATA\n"
                  "From: <[e-mail]>\n"
                  "To: <[e-mail]>\n"
                  "Subject: Test\n"
                  "Le corp c'est ici =)\n"
                  ".\n"
                  "QUIT\n";

I don't understand why it don't work because the same command work when I use it manualy in console. :/

If it can help you, I'm on Ubuntu and... I'm here if you need more informations :)

Thank in advance ;)

[coder777]

One possible source of this problem could be that you don't wait for an answer of the server when sending another message/command.

[blabla32]

I try it in this time this solution but I have a another problem VERY strange... Bad syntax error... The code is EXACTLY the same, but when I send it one by one I have this error on the next command:

char FROM[] = "MAIL FROM:<[e-mail]>\n";
send(sock, FROM, sizeof(FROM)+2, 0);

return:

500 5.5.2 Error: bad syntax

The HELO smtp... goes well but the rest not work. It's the same error for each instruction when they are send one by one.
I don't understand why it don't work with the same SMTP source code :/

I think my first problem is something like that too. But why "bad syntax error"? It's strange... Or I have don't understand something ^^'

[coder777]

Why this sizeof(FROM)+2?
Besides the trailing zero you send two invalid bytes of data. I'd say that even the trailing 0 is a problem.

You may consider to use a library for this. POCO has already this functionality:

http://pocoproject.org/docs/

See Net/Mail

[blabla32]

+2 It's an error, I was testing a solution but it's not good.
With or without +2 the return it's always the same.

Thank you for the library but, I prefere make a mail sender by myself to really understand how it to work :)

This is my source code without +2 (sorry again):

char FROM[] = "MAIL FROM:<[e-mail]>\n";
send(sock, FROM, sizeof(FROM), 0);

And the return is a same, bad syntax.

[coder777]

You're still transmitting the terminating 0. Better use strlen(...) instead of sizeof():

char FROM[] = "MAIL FROM:<[e-mail]>\n";
send(sock, FROM, strlen(FROM), 0);

[EDIT]
You might want take a look at code project:

http://www.codeproject.com/Articles/28806/SMTP-Client

[blabla32]

With sizeof or strlen the return is a same :/ I have also try to write manually the lenght and always this bad syntax error...

I have see your link but my answer isn't here :/

[coder777]

I suggest to take a closer look.

For instance

Each line sent by the client ought to be finished by "\r\n".

You're sending just "\n"

The correct order of request/response is certainly important too.

[blabla32]

If I don't say a foolishness, the \r is use to return to the beginning of the line and \n to jump a line on Windows. On linux the \n is sufficient to jump a line and back to his beginning. Therefore, \r is useless on linux. I have still tried with \r and don't work either :/

[coder777]

Do not mix concepts.

The default end of line for windows is "\r\n"
The required end of line for SMTP is "\r\n"

So, if you store text with a text editor under windows it is very likely that all line endings are according to the requirement of SMTP

I don't understand why it don't work because the same command work when I use it manualy in console. :/

This is a strong hint that you have still problems with the line endings. Replace all line endings that currently have only "\n" with "\r\n"

[blabla32]

Ok, sorry, I did not know \r\n it's required for SMTP, I thought that \n enough :)

But I have always the same problem ^^'

[blabla32]

Solve :D

The problem was that I store the mails data in one cell instead allocate one data by cell.

This is my new source code:

    char HELO[4][100] = {"HELO smtp.gmail.com\n",
                        "MAIL FROM: <[e-mail]>\n",
                        "RCPT TO: <[e-mail]>\n",
                        "DATA\r\n"};

    char DATA[4][100]   {"From: <[e-mail]>\n",
                        "To: <[e-mail]>\n",
                        "Subject: Test\n",
                        "Le corp c'est ici =)\n"};

    char QUIT[2][100]   {".\n",
                        "QUIT\n"};

    for(int i = 0; i<4; i++)
    {
        send(sock, HELO[i], strlen(HELO[i]), 0);
        recept_S(sock);
    }

    for(int i = 0; i<4; i++)
        send(sock, DATA[i], strlen(DATA[i]), 0);

    for(int i = 0; i<2; i++)
    {
        send(sock, QUIT[i], strlen(QUIT[i]), 0);
        recept_S(sock);
    }

Thank you very much to your help ^^