I cannot send mail from the server (notifications) per my postfix MX is setup to reject non fully qualified ehlo domainname (those with a domain name not fully qualified)
I get this form urbackup server htt interface when I set the email settings with a test email address:
Sending test mail failed. Error: Error(ec=55), RCPT failed: 504
From rfc 5321 4.1.4:
The SMTP client MUST, if possible, ensure that the domain parameter
to the EHLO command is a primary host name as specified for this
command in Section 2.3.5. If this is not possible (e.g., when the
client’s address is dynamically assigned and the client does not have
an obvious name), an address literal SHOULD be substituted for the
domain name.
curl strip domain from hostname (curl-7.52.1/lib/curl_gethostname.c and advertise so) even though the SMTP rfc tells nodename is not supported 
One can get curl to send a FQDN in ehlo/helo https://curl.haxx.se/mail/lib-2011-04/0066.html; That is: extend the url with a slash and the fqdn or ip litteral
smtp://target_host:taget_port/fqdn_sender_host
I tested this with curl command line client. Now I want to add a field helodomain to MailServer and set it to the fully qualified domain name of the backup server in urbackupserver/ClientMain.cpp getMailServerSettings.
Then check this field and add the extension to the smtp url in urlplugin/UrlFactory sendMail.
Could you tell me if there is a function to get the backup server IP or even better fqdn ?
If the IP, should I get the host with LookupService LookupHostname ?
Or move fileservplugin/CUDPThread.cpp getSystemServerName to a common location …
Cheers,
Alban
PS: The ip litteral would be a string with the ip enclosed in square brackets. Since rfc 5321 the extra comment aside the ip litteral is obsolete.