On 09/13/2013 12:56 PM, Timothy Murphy wrote:
If you upgrade from CentOS-5 to CentOS-6, which I imagine the vast majority of people did, then sendmail remains the current MTA.
that's a lot to assume. Most people I know professionally do not upgrade their rhel/centos servers. The debian crowd does, but they do have much shorter release cycles :-)
However, this is only a tiny point, since the document mentions "yum remove sendmail" as an alternative.
Firstly, after following the instructions meticulously, I found that I could not send out mail because (according to /var/log/maillog) the From address was tim@localhost.localdomain , and this was rejected by the recipient host or rather his ISP.
tim@localhost.localdomain MAIL FROM domain does not exist (in reply to MAIL FROM command)
I cured this by adding tim tim@gayleard.eu to /etc/hosts . I don't know if this is the best way to go about it?
That is a very odd hosts file entry :-). From man 5 hosts, section EXAMPLES:
127.0.0.1 localhost 192.168.1.10 foo.mydomain.org foo 192.168.1.13 bar.mydomain.org bar
This is typically caused by having your hostname set to localhost (or loaclhost.localdomain). Your hostname should reflect your fqdn.
If you mean $myhostname in /etc/postfix/main.cf then that is not the cause; it was set to my fqdn. Also it is set in /etc/sysconfig/network. And it is the name given by "uname -a". I'm not sure where else it can be given?
unless your fqdn is in DNS or in your hosts file, postfix does not know about that:
http://www.postfix.org/postconf.5.html#myhostname
So in order to find out what postfix thinks $myhostname is in its default settings, try this:
# postconf -d | grep myhostname
If you set a fqdn in myhostname, then you will not have that problem.
After correcting this, I found my email was still rejected, with the message "Blacklisted by Spamhaus"! I read in http://www.spamhaus.org/pbl/query/PBL814205 that 'the reason is simply that you need to turn on "SMTP Authentication"'
The bit at the top of the Spamhaus link says it all really - as a matter of *policy*, Spamhaus and/or your ISP has decided that you shouldn't be sending email direct from that IP address as it's residential / dynamic / whatever. Either way, as a result 90% of the internet is going to reject your mail. You will need to relay all outbound email through your ISPs smarthost to achieve any sort of deliverability.
Exactly. So perhaps this should be mentioned in the CentOS document http://wiki.centos.org/HowTos/postfix?
that is nothing postfix/centos specific, IMO. Trying to run an MTA on a dial-up host is an exercise in futility. You may agree of disagree whether this is fair, but it is a fact. So if someone adds a warning in the wiki about that, fine, but it has nothing to do with centos or postfix.
If you want to have a test postfix server with an acceptable IP address, get yourself a vm on any cloud provider. Then you will not be blocked unless you start spamming :-) . Those vm's are very affordable (from 5$/month on).