POP3 Relaying

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millvalley
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POP3 Relaying

Post by millvalley » 2020-09-25 16:59

I'm investigating the implementation of a POP3 Relay to provide a stepping stone from a telephony Mail client in a customer's corporate network via a relay server in their DMZ to a mailbox in Google's GMail platform (akin to the use of IIS SMTP server or standard SMTP Traffic).
Does hMailServer support this or does it need to stage the mailbox locally to the hMailServer server?

As an aside doe hMailServer support Oauth2 and LSA connections to Google or just one or the other?

Many thanks
Rich

dejavou42
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Re: POP3 Relaying

Post by dejavou42 » 2020-09-25 17:19

hmailserver is very adaptable to most needs. From what I understand, you want hmailserver to connect to a pop3 server and forward those emails on to a gmail account? This is doable by using the external account function within a user of a domain. You could then use a rule or a route to forward the mail on to gmail.

If I recall correctly, you will need to create an app specific password to use between hmailserver and Google.

millvalley
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Re: POP3 Relaying

Post by millvalley » 2020-09-25 17:46

It's the flipside of that, the telephony system Mail Client initiates a POP3 Request to the GMail Mailbox and retrieves new email and holds it in the telephone system mail store. It worked with the on-prem Exchange implementation as they were on the same network, the client has migrated to Google from Exchange and needs the same functionality as it forms part of their work flow, unfortunately their firewall provider doesn't allow POP3 as a bypass rule through the DMZ, so the Mail client can't directly connect to Google.

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Re: POP3 Relaying

Post by dejavou42 » 2020-09-25 18:29

So, it sounds like you would do this:

1. Create a domain in hmailserver

2. Create an account within that domain

3. Within the account settings, set up an external account for the gmail account using the app specific password. Hmailserver will collect those emails into the local domain's account.

4. You can connect a mail client to the local hmailserver and customize a non-standard port to bypass the firewall's restrictions.

millvalley
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Re: POP3 Relaying

Post by millvalley » 2020-09-28 11:44

More like:

1. Telephony mail client initiates the POP request opening a connection the hMailServer in DMZ

2. hMailServer opens a connection to GMail and requests new mail from the required mailbox.

3. hMailServer returns new mail to the Telephony mail client.

4. Telephony system processes email and generates response

5. Telephony system Opens connection to IIS SMTP Server in DMZ and sends email.

6. SMTP server relays email to Gmail SMTP server.

palinka
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Re: POP3 Relaying

Post by palinka » 2020-09-28 14:19

millvalley wrote:
2020-09-25 17:46
It's the flipside of that, the telephony system Mail Client initiates a POP3 Request to the GMail Mailbox and retrieves new email and holds it in the telephone system mail store. It worked with the on-prem Exchange implementation as they were on the same network, the client has migrated to Google from Exchange and needs the same functionality as it forms part of their work flow, unfortunately their firewall provider doesn't allow POP3 as a bypass rule through the DMZ, so the Mail client can't directly connect to Google.
What about smtp? If yes, instead of using pop to retrieve mail from Gmail, have gmail FORWARD messages to hmailserver where the telephony system can retrieve via pop.

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mattg
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Re: POP3 Relaying

Post by mattg » 2020-09-29 01:02

millvalley wrote:
2020-09-28 11:44
More like:

1. Telephony mail client initiates the POP request opening a connection the hMailServer in DMZ

2. hMailServer opens a connection to GMail and requests new mail from the required mailbox.

3. hMailServer returns new mail to the Telephony mail client.

4. Telephony system processes email and generates response

5. Telephony system Opens connection to IIS SMTP Server in DMZ and sends email.

6. SMTP server relays email to Gmail SMTP server.
In hmailserver these aren't sequential

#2 would happen independently of #1
#1 would lead to 3, then to '4, 5 & 6' ('4, 5 & 6' may also be independent from #3)
I would use hMailserver SMTP rather than IIS SMTP, unless you are utilising the 'drop folder' feature of IIS
Just 'cause I link to a page and say little else doesn't mean I am not being nice.
https://www.hmailserver.com/documentation

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