Is the Provider SMTP limitation to its internal DNS resolution solved?


#1

Hi guys,

If I want to send an email to one of my ISP, I need to request this ISP DNS to get the IP address of its smtp server and of course use its link.

This was a trouble with previous firmware, because they couldn’t assure DNS resolution of the “SMTP service forwarding” to be made on the right DNS. Is it possible to know if it has been solved? And if yes to have few explanation on the way it’s done?

Best regards,


#2

Just to answer myself : it’s not. :frowning:

In my first test I was just in this special case when the balance has this good idea to use the right DNS at the “SMTP service forwarding” resolution time.

By the way, when you use this “SMTP service forwarding” feature, how often the balance looks for FQDN resolution to organize its DNAT rules?

Thank you for your answer,


#3

SMTP service forwarding will perform FQDN lookup every time when SMTP forwarding is triggered. SMTP forwarding will use LAN DNS Proxy to lookup. You can click the question mark next to LAN DNS Proxy Settings, and you can select the LAN DNS uses only specific WAN (this will affect all DNS traffic). I would like to see it can be workaround for you at this moment or not. And we will also discuss internally about your situation about SMTP forwarding.



#4

Dear Chan,

I’ve been using your work around since january but the solution doesn’t look to be satisfying enough. Sometime, I observed mail was not working and as it’s the case this morning, I decided to look in the log. Each time I loose connexion to this provider, I can see in the log:
Oct 23 19:47:23 balance-5a8c WAN: Orange disconnected (WAN failed DNS test)
Oct 23 19:47:32 balance-5a8c WAN: Orange connected (82.127.99.222)
Oct 23 19:47:48 balance-5a8c Failed to resolve smtp.orange.fr in performing SMTP forwarding for Orange.
Oct 23 22:45:48 balance-5a8c WAN: Orange disconnected (WAN failed DNS test)
Oct 23 22:45:58 balance-5a8c WAN: Orange connected (82.127.99.222)
Oct 24 01:27:58 balance-5a8c WAN: Orange disconnected (WAN failed DNS test)
Oct 24 01:28:07 balance-5a8c WAN: Orange connected (82.127.99.222)
Oct 24 01:28:23 balance-5a8c Failed to resolve smtp.orange.fr in performing SMTP forwarding for Orange.

Then, I think there is like a cache trouble that make all SMTP requests after that to fail for a while with this provider.

So I’m still interesting in going on finding a solution with you.

Regard EG


#5

Hi EG,

Please open ticket here for further checking. Do let us know which is your preferred DNS for SMTP lookup. Please turn on Remote Assistance as well.