Post by thread:[PIC:] SMTP, POP3 ?

On Wed, 21 Jan 2004 00:47:21 -0600, you wrote: >Does anyone have experience with SMTP and POP3 email protocols ? > Yes. >I'm trying to write C code for the PIC 18F452 to negotiate the connection to a server through an 802.11b wireless access point connection to the internet. I'm assuming you know that a TCP connection is required, that's the hard part. Beyond that, its just a text based conversation often done using a state machine. The best place to start is to read the RFC's. Using the RFC's you can simply telnet into the SMTP or POP server and issue commands (you might need to use line input mode, don't remember) to get a feel for how it all works. -- http://www.piclist.com hint: To leave the PICList piclist-unsubscribe-requestKILLspammitvma.mit.edu

MSullivan wrote: > Does anyone have experience with SMTP and POP3 email protocols ? Yes. I've written both POP3 and SMTP servers and additional software to form a whole mail queueing and forwarding system. What are your specific questions? You can't do much with these protocols without reading the specs, which in this case are RFCs. There is no substitute for going to the source and getting the definative answer. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com -- http://www.piclist.com hint: To leave the PICList .....piclist-unsubscribe-requestKILLspam.....mitvma.mit.edu

Olin, thanks for responding.... specifically.. how to negotiatate (or figure out how to negotiate) the connection to the mail server ? I have a PIC board with an 802.11b wireless card on it, and I have a wireless access point router connected to the internet through a cable modem. I can communicate to the PIC card using a PC with a wireless card on it, that goes through the access point (with TCP/IP). How do I negotiate the connection with the mail sever, from the PIC board...through the router? Will I have to send out IP addresses, passwords etc...... and what responses will I get and need to respond to? How do I determine that? Thanks, Mark Sullivan EraseMEmsullispam_OUTTakeThisOuTinsightbb.com {Original Message removed}

thanks Bob, how do I telnet into the SMTP/POP3 server? what is line input mode? ----- Original Message ----- From: "Robert Reimiller" <bobspam_OUTCERTSOFT.COM> To: <@spam@PICLISTKILLspamMITVMA.MIT.EDU> Sent: Wednesday, January 21, 2004 1:48 AM Subject: Re: [PIC:] SMTP, POP3 ? On Wed, 21 Jan 2004 00:47:21 -0600, you wrote: >Does anyone have experience with SMTP and POP3 email protocols ? > Yes. >I'm trying to write C code for the PIC 18F452 to negotiate the connection to a server through an 802.11b wireless access point connection to the internet. I'm assuming you know that a TCP connection is required, that's the hard part. Beyond that, its just a text based conversation often done using a state machine. The best place to start is to read the RFC's. Using the RFC's you can simply telnet into the SMTP or POP server and issue commands (you might need to use line input mode, don't remember) to get a feel for how it all works. -- http://www.piclist.com hint: To leave the PICList KILLspampiclist-unsubscribe-requestKILLspammitvma.mit.edu -- http://www.piclist.com hint: To leave the PICList RemoveMEpiclist-unsubscribe-requestTakeThisOuTmitvma.mit.edu

What you MUST do first is to get the RFCs for SMTP and POP3. There are many sources - I like faqs.org http://www.faqs.org/rfcs/rfc2821.html - SMTP defined. (although 821 is still mostly correct) http://www.faqs.org/rfcs/rfc1939.html - POP3 defined (and 1081 is also still mostly correct) You can then practice these protocols by telneting to the server. On your favorite workstation just enter the command telnet servername 25 This opens a connection to port 25 which is defined as the port for SMTP. Really it is just an opened socket that you send and receive ASCII command over. Dan MSullivan wrote: >thanks Bob, > >how do I telnet into the SMTP/POP3 server? what is line input mode? > >{Original Message removed}

Don't send me personal copies of your PIClist posts. I don't need to see the same message twice. MSullivan wrote: {Quote hidden}> specifically.. how to negotiatate (or figure out how to negotiate) the > connection to the mail server ? > I have a PIC board with an 802.11b wireless card on it, and I have a > wireless access point router connected to the internet through a cable > modem. I can communicate to the PIC card using a PC with a wireless > card on it, that goes through the access point (with TCP/IP). How > do I negotiate the connection with the mail sever, from the PIC > board...through the router? Will I have to send out IP addresses, > passwords etc...... and what responses will I get and need to respond > to? How do I determine that? None of this has anything to do with SMTP or POP3. For SMTP you first have to establish a TCP connection to port 25 of the server in the usual way. POP3 is the same, but uses port 110. You only start talking SMTP or POP3 after these have been established. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com -- http://www.piclist.com hint: To leave the PICList spamBeGonepiclist-unsubscribe-requestspamBeGonemitvma.mit.edu

MSullivan wrote: > how do I telnet into the SMTP/POP3 server? It depends on your telnet client, but it's usually: telnet <machine name> <port number> This works for TELNET that comes with Windows 2000. The port number for SMTP is 25 and for POP3 is 110. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com -- http://www.piclist.com hint: To leave the PICList TakeThisOuTpiclist-unsubscribe-requestEraseMEspam_OUTmitvma.mit.edu

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Wednesday 21 January 2004 22:05, you wrote: > thanks Bob, > > how do I telnet into the SMTP/POP3 server? what is line input mode? You do a telnet to port 25 for SMTP or 110 for POP3... then, you can communicate with it using the protocols specified in the RFC... for example, in POP3, you'll have to enter your USER xxxx and PASS xxxx command to get logged in followed by the STAT and LIST commands to get a list of emails and then the RETR command to get mails... > > {Original Message removed}

On Wednesday, Jan 21, 2004, at 06:00 US/Pacific, MSullivan wrote: > specifically.. how to negotiatate (or figure out how to negotiate) the > connection to the mail server ? > I have a PIC board with an 802.11b wireless card on it, and I have a > wireless access point router connected to the internet through a cable > modem. I can communicate to the PIC card using a PC with a wireless > card > on it, that goes through the access point (with TCP/IP). How do I > negotiate the connection with the mail sever, from the PIC > board...through > the router? Will I have to send out IP addresses, passwords > etc...... and > what responses will I get and need to respond to? How do I determine > that? I'm sorry, but you need to back up a few steps and learn a bit and learn how the internet "works" at a basic level, especially with respect to the layering of protocols. An SMTP client does not "negotiate a connection" with a mail server; it simply opens a TCP connection, using whatever tcp APIs are provided. the TCP layer handles the negotiation and "connection." A TCP connection does not 'work through a router"; it sends IP packets using internal APIs. The IP layer handles (more or less, using additional protocols like ICMP or ARP) figuring out which router to use. Writing SMTP code is easy; a nice ascii dialog. writing a complete internet stack containing all the layers needed to communicate over an 802.11b card is a major undertaking... BillW -- http://www.piclist.com hint: To leave the PICList piclist-unsubscribe-requestEraseME.....mitvma.mit.edu

MSullivan wrote: > Does anyone have experience with SMTP and POP3 email protocols ? This page has an example of the text protocol used for a pop3 transaction: http://www.wowarea.com/english/help/poptel.htm This is the rfc for pop3: http://www.faqs.org/rfcs/rfc1939.html Here is an example of an smtp script: http://www.aspheute.com/english/20001009.asp This page explains smtp in a little more detail: http://cr.yp.to/smtp.html This is the smtp rfc: http://www.faqs.org/rfcs/rfc2821.html Authenticating smtp can be a little complicated depending on the authentication scheme your isp uses, if you don't send mail from the same server you dialed up to. Bruce Douglas -- http://www.piclist.com hint: To leave the PICList EraseMEpiclist-unsubscribe-requestmitvma.mit.edu

Hello, ----- Original Message ----- From: "MSullivan" <RemoveMEmsulliEraseMEEraseMEINSIGHTBB.COM> To: <RemoveMEPICLISTspam_OUTKILLspamMITVMA.MIT.EDU> Sent: Wednesday, January 21, 2004 6:00 AM Subject: Re: [PIC:] SMTP, POP3 ? {Quote hidden}> Olin, > > thanks for responding.... > > specifically.. how to negotiatate (or figure out how to negotiate) the > connection to the mail server ? > I have a PIC board with an 802.11b wireless card on it, and I have a > wireless access point router connected to the internet through a cable > modem. I can communicate to the PIC card using a PC with a wireless card > on it, that goes through the access point (with TCP/IP). How do I > negotiate the connection with the mail sever, from the PIC board...through > the router? Will I have to send out IP addresses, passwords etc...... and > what responses will I get and need to respond to? How do I determine that? So far, two people have said that the best source are RFC's. It would be far more efficient for YOU to read the RFC's to determine exactly what you need to do rather than relying on someone to walk you through step-by-step. To make it easy, you can resolve the POP/SMTP server domain to an IP address beforehand and use that to connect. Otherwise, you'll have to implement a DNS client. Once you have the IP address, for POP3, you would initiate (3 way handshake) a connection to port 110 of the remote machine. Then, you proceed to send the necessary commands. This will take a bit of coding on your part. For POP3, the aforementioned RFC is RFC1939: http://www.networksorcery.com/enp/rfc/rfc1939.txt For SMTP, RFC821: http://www.faqs.org/rfcs/rfc821.html -Tim > > Thanks, > > Mark Sullivan > RemoveMEmsulliTakeThisOuTspaminsightbb.com > > -- http://www.piclist.com hint: To leave the PICList EraseMEpiclist-unsubscribe-requestspamspamBeGonemitvma.mit.edu

thanks.. if I'm understanding correctly... not sure I am because is not working...... I have a local network.... on it are a laptop... a desktop.... the PIC card I am developing code for.... and a router connected to a cable modem to the internet... the PIC card address is 192.168.0.20 ... desktop 192.168.0.2 ... laptop 192.168.0.10 ... router 192.168.0.1 ..... and the mailserver IP is 32.x.x.x .... so I ARP request and get a respone... then send SYN through TCP client..... and should get back an ACK flag.... but instead I get back RST (reset) flag.... because the mailserver is outside the 255.255.255.0 mask (ie 32.x.x.x compared to 192.x.x , the LAN router address is used ? to ARP? to send SYN to mailserver IP? {Original Message removed}

MSullivan wrote : > if I'm understanding correctly... I wouldn't bet on that... {Quote hidden}> not sure I am because is not > working...... I have a local network.... on it are a laptop... a > desktop.... the PIC card I am developing code for.... and a router > connected to a cable modem to the internet... the PIC card > address is > 192.168.0.20 ... desktop 192.168.0.2 ... laptop > 192.168.0.10 ... > router 192.168.0.1 ..... and the mailserver IP is 32.x.x.x .... > > so I ARP request and get a respone... What response ? > then send SYN Where to ? > through TCP client..... > > and should get back an ACK flag.... but instead I get back > RST (reset) flag.... Now, you do know how IP routing works, right ? In short, your "client" should see that the target IP address is outside the local netmask, and then send the request (route) through your router. Now, does the PIC software support routing ? > > because the mailserver is outside the 255.255.255.0 mask > (ie 32.x.x.x compared to 192.x.x , the LAN router addres > is used ? to ARP? to send SYN to mailserver IP? In a way... ...I think... Jan-Erik. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

On Fri, 23 Jan 2004, MSullivan wrote: > then send SYN through TCP client..... What software are you using on the PIC that requires you to know about SYN packets? > because the mailserver is outside the 255.255.255.0 mask (ie 32.x.x.x > compared to 192.x.x , the LAN router address is used ? to ARP? to send SYN > to mailserver IP? Since the mail server is off your LAN, you have to ARP for the router's address, then use the router's MAC address with the mail server's IP address for all the packets you are directing to the mail server. -- John W. Temples, III -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

> if I'm understanding correctly... not sure I am because is not > working...... I have a local network.... on it are a laptop... a > desktop.... the PIC card I am developing code for.... and a router > connected to a cable modem to the internet... the PIC card address is > 192.168.0.20 ... desktop 192.168.0.2 ... laptop 192.168.0.10 ... > router 192.168.0.1 ..... and the mailserver IP is 32.x.x.x .... > because the mailserver is outside the 255.255.255.0 mask > (ie 32.x.x.x compared to 192.x.x), By definition, if the netmask is 255.255.255.0 (it's a bit mask) then the local network is 192.168.0.0, not 192.x.x.x. The mailer server's network number would be 32.x.x.0 using your netmask. To compute a network number you bit-wise AND the IP address with the netmask. > so I ARP request and get a respone... > > then send SYN through TCP client..... > > and should get back an ACK flag.... but instead I get back > RST (reset) flag.... You don't specifically state it, but from the hints in your questions, I'm assuming you are layering SMTP/POP3 on top of TCP on top of IP on top of an Ethernet physical layer. Where did you get the TCP/IP & Ethernet layers running on your PIC? Do they work? Do you trust them to work? I don't think you have a clear understanding of how the TCP, IP, and Ethernet layers work. Your first question implies you are implementing the IP layer and interfacing directly to the Ethernet layer (ARP). Yet later questions imply you are working at the TCP layer. I think you need to spend some time studying up on IP, TCP, Ethernet encapsulation of IP, etc. All these subjects are well covered by various RFCs. And then provide a clear description of how your application is trying to hook into the layer(s) of whatever network stack you are using. > the LAN router address is used ? to ARP? to send SYN If the destination IP address is not on the local network, then you need to use your routing table to determine what gateway IP address is most appropriate for traffic destined for any specific remote IP network. Decision is usually made based on IP address but may include link cost metrics or other factors. The easiest & most common case for end nodes is a single default gateway. It is normally the IP address of the router, DSL box, etc on your local network and appears to be 192.168.0.1 from your above description. In this case, all traffic that isn't destined for the local IP network is sent to the gateway router's IP address. Lee Jones -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

On Fri, 23 Jan 2004, Lee Jones wrote: > The easiest & most common case for end nodes is a single > default gateway. It is normally the IP address of the > router, DSL box, etc on your local network and appears to > be 192.168.0.1 from your above description. In this case, > all traffic that isn't destined for the local IP network > is sent to the gateway router's IP address. No, it is not. It is sent to the desired destination IP address, using the router's MAC address. -- John W. Temples, III -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics