What are POP3, IMAP, and SMTP?

☝️ POP, POP3, IMAP, and SMTP are all acronyms used in configuring email. We'll look at what they mean and how they relate.

☝️ POP3, IMAP, SMTP
POP3: Post Office Protocol version 3, used to download email.
IMAP: Internet Message Access Protocol, used to access email via multiple devices.
SMTP: Simple Mail Transfer Protocol, used to send mail from one computer or server to the next.

Chapters
0:00 POP3, IMAP, and SMTP
0:50 POP: Post Office Protocol
2:00 IMAP: Internet Message Access Protocol
3:50 SMTP: Simple Mail Transfer Protocol
5:00 Webmail works differently, mostly

More Ask Leo!

#askleo #POP3 #IMAP

[sennthemanwin]

Leo, at this point you deserve a wikipedia. Thanks for helping us out and being our guide around the internet!

[HartmutWSager]

Hi Leo. A nice simple and clear explanation. But a bit too simple re IMAP itself and also re IMAP vs POP3.
1. IMAP is a 2-way sync, unlike POP3's one-way retrieval.
2. IMAP does a 2-way sync on an entire collection of folders and subfolders, unlike POP3's one-way retrieval of Inbox only. This would matter a lot if a user currently has a whole folder tree of e-mails on the server, which a Webmail user could easily have done over time, as part of organizing his/her e-mails.
3. Though a POP3 mail client normally deletes the retrieved e-mails from the server, most POP3 mail clients do have the option of leaving mail on the server. Furthermore, some mail servers have an option to ignore a mail client's "delete from server" setting.

[brightonmusic]

Thank you! As always, fantastic useful information

[aldrinjohnencina]

thank you so much. very clear explanations.

[kylemlsantos]

Exceptionally clear explanations. Thank you greatly, Leo!

[malchikovma]

Great explanation, thank you. I used the gmail for most of the time and didn't know these protocol purpose. And I'm a programmer. What a shame. Well, now i know.

[keithswalley]

I have used MS Outlook for likely 15+ years. I still use a Pop3 setup. Back when I used an iPhone (3.5+ years ago), I could access my e-mail on the iPhone when traveling, delete most of the mails, and still be able to access those (phone) deleted mails when I returned to my PC at home. When I switched to an Android phone, I discovered that it needed an imap account for it to work on the phone. Due to research that I do, I want to preserve certain (now a couple of thousand) e-mails on my PC. So, I do not use e-mail on my phone as deleting it on my phone would delete it everywhere....so I'm told. I want everything on my PC, where I regularly back up, and will cull it from there. So, I stay with pop3. 'Course, now that I'm old, I can wait until I return home to read my e-mails, but phone access would be convenient.

Now, the additional issue is how to save all of those .pst e-mails on my PC to a readable format if and when I leave MS Outlook.

[inexpensivegames]

Leo thank you for the Ip address video saved me a heart attack!

[Jack-fsim]

thanx hope you do a WSAP modem settings explain.thanx again

[shadowminister]

Thankyou Leo for your great videos.
My son is an IT person; me, not so much. Some years ago, he set up Thunderbird for me and it sounds like he used IMAP, because when I deleted emails on my PC, I still had copies on my other devices. I don't use Thunderbird now that I have Gmail, but at the time, I found it annoying because I needed to delete the messages twice. In hindsight, I can see not losing your original, has a lot of advantages.

[E-MATHSTUTORS]

my outlook email corrupted due to the fact i added multiple emails (three emails ) on outlook account; what can i do to rectify the problem?

[NoEggu]

I used to use Outlook 2007, configured with POP3.
That version of Outlook had an option to leave the e-mail on the server (download, but do not delete).

I do not know what current versions of Outlook have, or what other e-mail clients have. But if I had to guess, I would say that they, too, can be configured the same way (to not delete your messages from the e-mail server).

I once heard that POP3 does its business in the clear, whereas IMAP creates an encrypted tunnel between you and the e-mail server -- making it a more secure choice for exchanging e-mail messages between you and the e-mail server. I might be mistaken, and not interested enough to search for the answer. Maybe someone else can elaborate.

[billz]

Thanks but how do I find out which one I have for my Gmail and Yahoo Mail?
Each of my Mail accounts have "missing" / deleted emails?

[anthonyrude]

Which one is best for replying to emails?
Does replying to an email from an email address where the original email was routed to a new email address through pop3 IMAP or SMTP affect domain reputation because it's sent from a different address?

[AzminGamespot]

Hey can you help me, I remember my email and password but the problem is it's asking if it's really me trying to sign in, i dont have my phone with me so i hate how even though it's right password but still asking if it me

[jamesweber]

I cannot send a gmail email to myself using Thunderbird. Do I have a setting wrong in Thunderbird ?

[franciscohorna]

which one dose web based email use outlook and gmail