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Dynamic DNS question

Dynamic DNS question
« on: December 29, 2016, 08:16:47 AM »
Hi all. and compliments of the season.
Have a client with a really bad internet connection, that is, more down than up. They have wireless internet backup, but of course that doesn't have a static IP. I have setup a NoIP account so that they can have mail flow. I have been at this for 2 day now with no joy at all.

The server is a SME 8, server-only mode. I have setup an MX record with a greater value pointing to the NoIP account/host. Before I jump out of a window, is it at all possible to have SME in this configuration? Using both the NoIP and the regular DNS? (Don't think so, but then again...)

Sorry if this is a silly post, but I need some sort of help..

thank you and best to all
gb

Offline Jáder

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Re: Dynamic DNS question
« Reply #1 on: December 29, 2016, 10:21:57 AM »
Hi,

I´m not sure if I understand your question, but SME works with dinamic IP.
The real problem is ISP very often block ports on dinamic IP address (as port 80, 25 ...) so you cannot have a server behind it.

If your ISP do not block ports it´s just a matter of external DNS configuration.
Create a primary MX pointing to your fixed (and unreliable) IP and a secondary MX pointing to your dinamic ip.
tip: You can create an  CNAME (alias) entry on your domain DNS as "dsl.mydomain.com"  pointing to mycompany-dsl-link.noip.com

AFAIK there are no problem to SME to get e-mails or http connections from two different IP/ISP... I´ve several clients using it this way.

Regards
Jáder
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Re: Dynamic DNS question
« Reply #2 on: December 29, 2016, 11:02:13 AM »
Hi Jader,

thanks a million for that.. Wasn't sure as I had been working at it for a long time and might have got muddled up...Looks like it's working now...
Thanks again and happy new year to all..all the best!

Offline Stefano

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Re: Dynamic DNS question
« Reply #3 on: December 29, 2016, 11:25:54 AM »
Hi bosco555

I had some similar issues some time ago with a customer of mine..

I solved pointing the MX record of the domain on a dyndns host and configuring the dyndns client on SME.. IOW, the MX record (but it wil work for any DNS entry) is bound to a dyndns host
Consulente di Smeserver.it -  Soluzioni e supporto su Sme server in Italia

Offline brianr

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Re: Dynamic DNS question
« Reply #4 on: December 30, 2016, 11:34:01 AM »
Hi bosco555

I had some similar issues some time ago with a customer of mine..

I solved pointing the MX record of the domain on a dyndns host and configuring the dyndns client on SME.. IOW, the MX record (but it wil work for any DNS entry) is bound to a dyndns host

All the MX records for my customers (not so many now) point to the SMeServer using DYNDNS entries, even the static ones, as it gives me a symbolic name to use to access the server.
Brian j Read
(retired, but still looking after 5 SME installations)
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Re: Dynamic DNS question
« Reply #5 on: January 05, 2017, 01:21:27 AM »
What I found is that email doesn't get through mobile devices eg tablets and phones when the main line is down and the NoIP kicks in. Local PCs and mobile devices in the office are OK though. Also webmail does not work using https://mail.company.com/webmail but its OK (obxiously) if you use the temporary IP address.

The MX records at the registrar are 10 mail.company.com and 30 mail.noip.com.

Is there anything I missed here?

thanks again

Offline Jáder

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Re: Dynamic DNS question
« Reply #6 on: January 23, 2017, 11:42:36 AM »
What I found is that email doesn't get through mobile devices eg tablets and phones when the main line is down and the NoIP kicks in. Local PCs and mobile devices in the office are OK though. Also webmail does not work using https://mail.company.com/webmail but its OK (obxiously) if you use the temporary IP address.

I'm not sure if I understand your problem... but let's try:
1) if you have a fixed IP pointing by external DNS to mail.yourcompany.com and that link is down or failing, external devices are no supposed to get mail using that route.
You should create a roundrobin DNS entry with both external names (one for each link) as:
office.mydomain.com  pointing to mail.mydomain.com and noip.mydomain.com

later, you should configure your external devices to use office.mydomain.com

Quote
The MX records at the registrar are 10 mail.company.com and 30 mail.noip.com.

Is there anything I missed here?

thanks again
2) The MX records are used by server to know where to delivery e-mail not by clients to read e-mails.
But it appears to be right if you wish to let others try to delivery FIRST at mail.company.com and LATER at mail.noip.com

Is this helpfull ?

Regards
« Last Edit: January 23, 2017, 11:44:33 AM by Jáder »
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Re: Dynamic DNS question
« Reply #7 on: January 24, 2017, 07:56:59 AM »
Hi Jader and thanks for the reply. All I can create is a CNAME record like: office.mydomain.com pointing to noip.mydomain.com.

When the main line is down, noip will come into effect and I will have to change all the mobile devices to office.company.com in order to receive mail?

thanks again
gb

Offline Jáder

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Re: Dynamic DNS question
« Reply #8 on: January 25, 2017, 02:58:48 AM »
WARNING: I'm not sure about this, you should try to ask to someone better than me!

I'd create an A record with TWO IPs (for fixed IPs!)  something like office.mydomain.com with IP of link A and IP of link B.

I'm not sure how this would work for TWO other CNAMES (or even if this is possible).

The final GOAL would be configure your clients (as mobiles clients for e-mail) with this office.mydomain.com hostname so they can access your services running behind those two fixed IPs. Again ... not sure how this can be done on DynDNS names.
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