First off, when posting info about an issue, you should change anything that is a possible way for others to 'attack' your system - you can see I changed your IP to a generic one, and any actual domain names to generic. This is for your own protection since anyone can read these forums.
Quote:
May 5 08:30:41 nus220 sendmail[29817]: k44MUbM29801: to=miamikool@otherplace.com, ctladdr=kndsep (40105/40025), delay=00:00:04, xdelay=00:00:03, mailer=relay, pri=121651, relay=cdn-mail.somewhere.com.au. [10.10.138.138], dsn=2.0.0, stat=Sent (IAA03690 Message accepted for delivery)
Does the last part stat=Sent (IAA03690 Message accepted for delivery) mean that the msg has gone successfully?
Yes, the message was accepted by the cdn-mail relay - that is probably still part of your network but it did leave your system. You should check with the person who runs cdn-mail.somewhere.com.au and see if they can verify the message was forwarded on to the receipent.
Version 8.11.6+Sun
<---version of sendmail you are running
Compiled with: LDAPMAP MAP_REGEX LOG MATCHGECOS MIME7TO8 MIME8TO7
NAMED_BIND NDBM NETINET NETINET6 NETUNIX NEWDB NIS NISPLUS
QUEUE SCANF SMTP USERDB XDEBUG
<-----sendmail was compiled with support for these - looks normal
============ SYSTEM IDENTITY (after readcf) ============
(short domain name) $w = nus220
(canonical domain name) $j = nus220.in.somewhere.com.au
(subdomain name) $m = somewhere.com.au
(node name) $k = nus220
========================================================
this looks correct also - there are times when DNS isn't set up correctly that these would be wrong, possibly being an issue with slow mail service or no mail service
ADDRESS TEST MODE (ruleset 3 NOT automatically invoked)
Enter <ruleset> <address>
----------------------------------------------------------------------
No errors in output - looks okay
Quote:
Also i would like to know how does mailx work internally? as in does it store the mails in a buffer before sending it? and what happens if the mail is not sent? where does that mail go if it was not sent successfully?
Mail will be sent to /var/spool/mqueue - it will be attempted to be sent every XX minutes (see next note). If it doesn't go, it will be attempted again every XX minutes (see next note) until XX hours. After XX hours, if the message is still not sent, the sender should recieve an email that the email still hasn't gone and is still trying. After a final attempt, the sender should get an email that it hasn't gone (for whatever reason) and sendmail has stopped trying (this is when the email would be deleted).
All the XX minute/hour stuff should be in your /etc/mail/sendmail.cf file - I believe the default is that sendmail attempts every 15 minutes to send all email in the queue. After 4 hours, it will notify the sender if it hasn't gone. After 8 hours it will notify the sender it has given up. The reason it does this is that the mail relay to the final receipent may be down - this allows email to be sent later when whatever the issue is to be resolved. These times I put may not be correct - it's been awhile since I've looked/changed them so it may just be what my server has as 'default'
Read more at
www.sendmail.org