Smtp & pop3

DerekAustin26

SMTP = Sending email
POP3 = Retrieving email

is this correct?

I thought when your online and connected in Microsoft Outlook you are already connected to the SMTP server, so there is no use for the POP3 protocol.

If so, what are the specific reasons why you would use POP3?

tiersten

SMTP is for talking to a mail server and for mail servers to talk to each other.

Once email is delivered to your local mail server using SMTP, it is left in a mailbox for you.

POP3/IMAP is to pick up your email from a mailbox.

DerekAustin26

i just said that.

CChN

DerekAustin26 wrote: »

I thought when your online and connected in Microsoft Outlook you are already connected to the SMTP server, so there is no use for the POP3 protocol.

POP3 is an application-layer protocol that makes use of TCP as it's transport protocol. Once a TCP 3-way handshake establishes a connection between your client and mail server, POP3 can do its mail grabbing magic. Without POP3 you can't pull your mail from the server to your user agent.

gojericho0

POP3 also pulls a copy of the mail so your client almost acts like its own mailbox. With IMAP you are actually interacting with the mailbox on the server. So for example with POP you delete a mail on the client it will still be on the mail server, with IMAP you delete the mail on the client and it will also be deleted on the server

Mishra

DerekAustin26 wrote: »

i just said that.

Thats not what you said. You said that SMTP was for sending mail and POP3 was for receiving mail. These 2 references do not go together.

Tiersten said that SMTP was used for communication which means sending/receiving.

In order to get a good understanding of what is going on; telnet into a SMTP server using port 25 (smtp port) [telnet your.smtpserver.com 25] then google how to talk SMTP and try to send a piece of mail to a correct address. You should be able to do this on most mail serves, even yahoo/google.

dynamik

DerekAustin26 wrote: »

I thought when your online and connected in Microsoft Outlook you are already connected to the SMTP server, so there is no use for the POP3 protocol.

If you're talking about using Outlook in conjunction with Exchange, it uses MAPI (or RPC over HTTP if you're off your network).

DerekAustin26 wrote: »

i just said that.

You asked for confirmation

DerekAustin26

Mishra wrote: »

Thats not what you said. You said that SMTP was for sending mail and POP3 was for receiving mail. These 2 references do not go together.

Tiersten said that SMTP was used for communication which means sending/receiving.

In order to get a good understanding of what is going on; telnet into a SMTP server using port 25 (smtp port) [telnet your.smtpserver.com 25] then google how to talk SMTP and try to send a piece of mail to a correct address. You should be able to do this on most mail serves, even yahoo/google.

That is what i said. SMTP is for sending email and thats it. You receive email on the SMTP Server, but you dont retrieve it.. Make sense?

Tiersten said the exact same thing as me but more extensive and in different words.

Now back to the question...

DerekAustin26

I thought when your online and connected in Microsoft Outlook you are already connected to the SMTP server?

Is this true or false?

CChN

DerekAustin26 wrote: »

I thought when your online and connected in Microsoft Outlook you are already connected to the SMTP server?

Is this true or false?

Read my post!

You have established a TCP connection. Now, what protocol is going to DL your e-mail after doing so?

kalebksp

DerekAustin26 wrote: »

SMTP is for sending email and thats it.

As Mishra and Tiersten said, SMTP is used by email servers to send and receive mail. When Server A sends email to email Server B, Server A is sending using SMTP and Server B is receiving using SMTP.

gojericho0

SMTP pushes email, POP3 pulls

DerekAustin26

kalebksp wrote: »

As Mishra and Tiersten said, SMTP is used by email servers to send and receive mail. When Server A sends email to email Server B, Server A is sending using SMTP and Server B is receiving using SMTP.

I strongly disagree.. I may have started this forum, but I do know what SMTP is. SMTP is only for sending email. look it up. The SMTP SERVER "Receives" the mail, but the Protocol itself is not retrieving ****. Thats for the POP3 protocol.

DerekAustin26

CChN wrote: »

Read my post!

You have established a TCP connection. Now, what protocol is going to DL your e-mail after doing so?

That would be the POP3.

DerekAustin26

CChN wrote: »

Read my post!

You have established a TCP connection. Now, what protocol is going to DL your e-mail after doing so?

Okay one more question then... If POP3 is pulling the mail off the SMTP Server, then where is the mail going? Because obviously its not going to your harddrive unless you are archiving(pst file etc..)

What is holding the mail after you retrieve it from the SMTP Server?

Before you say "Mail Client" - well the Mail Client is just software and software is ran by your RAM. I want a clear cut answer here..

Where is the mail stored after you retrieve it from the SMTP Server?

rwwest7

DerekAustin26 wrote: »

SMTP = Sending email
POP3 = Retrieving email

is this correct?

I thought when your online and connected in Microsoft Outlook you are already connected to the SMTP server, so there is no use for the POP3 protocol.

If so, what are the specific reasons why you would use POP3?

Please define what you mean by "online". Do you mean sitting at home with Outlook connected to your ISP mail account? If so, you're using SMTP/POP3. If your at work/a business and connect to an Exchange server on you local network, then your not using SMTP/POP3.

gojericho0

DerekAustin26 wrote: »

I strongly disagree.. I may have started this forum, but I do know what SMTP is. SMTP is only for sending email. look it up. The SMTP SERVER "Receives" the mail, but the Protocol itself is not retrieving ****. Thats for the POP3 protocol.

What everyone has been telling you is absolutely true

SMTP protocol can and is used to receive email, but is done so primary server to server. It just can't pull it on demand. It has to wait until a SMTP session is established from another server.

POP3 can pull email and is why it is used on clients. So you can receive on demand.

tiersten

DerekAustin26 wrote: »

I strongly disagree.. I may have started this forum, but I do know what SMTP is. SMTP is only for sending email. look it up. The SMTP SERVER "Receives" the mail, but the Protocol itself is not retrieving ****. Thats for the POP3 protocol.

So what are you asking exactly if you know what SMTP and POP3 do?

You can run a full SMTP server on your local PC if you want and use that to receive/send email if you really want to. If you don't want to do this then you'd want your email to be stored in your mailbox on a remote server and picked up via POP3/IMAP.

gojericho0

DerekAustin26 wrote: »

Okay one more question then... If POP3 is pulling the mail off the SMTP Server, then where is the mail going? Because obviously its not going to your harddrive unless you are archiving(pst file etc..)

What is holding the mail after you retrieve it from the SMTP Server?

Before you say "Mail Client" - well the Mail Client is just software and software is ran by your RAM. I want a clear cut answer here..

Where is the mail stored after you retrieve it from the SMTP Server?

POP stores mail on your hard drive. Thats why you have to download the mail and you can delete or move messages without it effecting the server.

This is not normally used in an enterprise environment because it is not portable, scalable, secure, and very hard to manage

tiersten

DerekAustin26 wrote: »

Okay one more question then... If POP3 is pulling the mail off the SMTP Server, then where is the mail going? Because obviously its not going to your harddrive unless you are archiving(pst file etc..)

Before you say "Mail Client" - well the Mail Client is just software and software is ran by your RAM. I want a clear cut answer here..

Where is the mail stored after you retrieve it from the SMTP Server?

I don't know why you're discounting your mail client. Why do you say it obviously isn't going to your hard drive?

Assuming you're not using IMAP or Exchange which store email on the remote server then it is all kept in a PST file by Outlook. If you are using IMAP or Exchange then Outlook will ask the server what email is in the particular folder you're interested in and show you the contents.

kalebksp

DerekAustin26 wrote: »

I strongly disagree.. I may have started this forum, but I do know what SMTP is. SMTP is only for sending email. look it up. The SMTP SERVER "Receives" the mail, but the Protocol itself is not retrieving ****. Thats for the POP3 protocol.

You are right, it doesn't retrieve anything, as I'm sure you know it's a push only, it does not pull data. But from a technical perspective, one end of the connection is receiving mail. That's all I meant. You really don't need to get upset over these sort of things, it's not a big deal.

rwwest7

tiersten wrote: »

I don't know why you're discounting your mail client. Why do you say it obviously isn't going to your hard drive?

Assuming you're not using IMAP or Exchange which store email on the remote server then it is all kept in a PST file by Outlook. If you are using IMAP or Exchange then Outlook will ask the server what email is in the particular folder you're interested in and show you the contents.

Exactly. If you're using POP3, then the message is stored on your local hard drive. You can configure Outlook to leave a copy on the server or remove it from the server, thats your choice. But there is always a copy on you local hard drive IF you're using POP3.

DerekAustin26

gojericho0 wrote: »

What everyone has been telling you is absolutely true

SMTP protocol can and is used to receive email, but is done so primary server to server. It just can't pull it on demand. It has to wait until a SMTP session is established from another server.

POP3 can pull email and is why it is used on clients. So you can receive on demand.

So your saying that Outlook's "Send/Receive" button is an active "pop3" protocol button?

Cuz as soon as you hit "send/receive" you will start to receive mail soon if not already downloaded.

gojericho0

yes and the smtp you have on outlook is only the client. like mirsha said, try to telnet to an smtp server and mess around with a few commands. you will see what your client is doing behind the scenes

DerekAustin26

rwwest7 wrote: »

Exactly. If you're using POP3, then the message is stored on your local hard drive. You can configure Outlook to leave a copy on the server or remove it from the server, thats your choice. But there is always a copy on you local hard drive IF you're using POP3.

Here's my understanding.. Obviously we have established pop3 "pulls" but now the question is.. where's it going next?

And what i understand, is that
A: Its going to your harddrive
or
B: it's going to a remote server/domain
depending on your configuration

That sound right?

tiersten

DerekAustin26 wrote: »

Here's my understanding.. Obviously we have established pop3 "pulls" but now the question is.. where's it going next?

And what i understand, is that
A: Its going to your harddrive
or
B: it's going to a remote server/domain
depending on your configuration

That sound right?

The Send/Receive button does several things. You can see what it is doing if you check the box to show details.

For POP3:

It looks into its outgoing folder to see if there are any emails it needs to send. If there are then it will open a connection to the configured SMTP server and then send the email. It will then move the email into the sent items folder.

It will also connect to your POP3 server and look to see if there are any new emails that have appeared since it last checked. If there are then it will either just download the headers or the full email depending on how you've configured Outlook. It will then save the email into a local PST file.

For IMAP:

It does the same checking the outgoing folder process as POP3.

It will connect to your IMAP server and look to see if there are any new emails. If there are any then it will download the header details so it can display the relevant details to you. The email is still on the remote server at this point. It will stay there until you delete it or save it to a local folder.

kalebksp

DerekAustin26 wrote: »

Here's my understanding.. Obviously we have established pop3 "pulls" but now the question is.. where's it going next?

And what i understand, is that
A: Its going to your harddrive
or
B: it's going to a remote server/domain
depending on your configuration

That sound right?

With POP3 (with Outlook as an example) the email is saved into the PST file and then deleted from the server. In most cases the POP3 client has to tell the server to delete the messages. You can actually change the configuration and tell Outlook (the POP3 client) not to delete those messages, in which case you could retrieve them again from a different client.

You could replace POP3 with IMAP, in which case IMAP would pull the messages and folders structure from the server and display it to the client. However the data is only used to cache the messages, all the data is left on the server.

rwwest7

DerekAustin26 wrote: »

Here's my understanding.. Obviously we have established pop3 "pulls" but now the question is.. where's it going next?

And what i understand, is that
A: Its going to your harddrive
or
B: it's going to a remote server/domain
depending on your configuration

That sound right?

It's not going to a server, it's already on the server. POP is just the protocol that transfers it to your hard drive. Like FTP is used to transfer files from an FTP server to your local computer. POP

lildeezul

gojericho0 wrote: »

POP stores mail on your hard drive. Thats why you have to download the mail and you can delete or move messages without it effecting the server.

This is not normally used in an enterprise environment because it is not portable, scalable, secure, and very hard to manage

please read all the post

gojericho0

lildeezul wrote: »

please read all the post

huh? i was just trying to clarify the storage question

/usr

OP, you need to clarify. A lot of people are trying to help you and you're replying with smart ass comments.

First of all. Why is this in the CCNA forum?

Second, could you please clarify what the hell you're asking?


SMTP is for sending mail, correct.
POP3 is for receiving mail, correct.

is this correct?

Yes.

I thought when your online and connected in Microsoft Outlook you are already connected to the SMTP server, so there is no use for the POP3 protocol.

When you are "online" in Microsoft Outlook, what do you mean?

If you are using a POP3/SMTP mail server in your Accounts, then you are never "online" with Microsoft Outlook. You connect when you hit "Send and Receive", or at a time interval if you have that selected. When you connect, you connect to your mail server. You use the POP3 protocol to download the mail from your mail server. You use the SMTP protocol when you're sending mail to your mail server.

If so, what are the specific reasons why you would use POP3?

To download the mail, sent by other people and queued on your mail server, to your mail client.


If I am missing something or am wrong in any aspect of this, please correct me. Otherwise, do you understand?