"need fully-qualified hostname" error

Question

Can someone please help me with a basic problem with setting up the mail server, I can't seem to get to first base. The following is a Terminal session using telnet to do some basic testing (with personal info substituted for generic names) -
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mbp-5:~ Tony$ telnet mailserver.mydomain 25
Trying 82.7.140.46...
Connected to mailserver.mydomain.
Escape character is '^]'.
220 mailserver.mydomain ESMTP Postfix
helo me
250 mailserver.mydomain
Mail from:myaddress@somedomain
250 2.1.0 Ok
Rcpt to:[email protected]
504 5.5.2 <me>: Helo command rejected: need fully-qualified hostname
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In my Server Admin/Mail/General settings I have the host name set to mailserver.mydomain
Can anyone give me a pointer please

Answer 1

Thanks for that info.
However, is the FQDN mailserver.example.com or example.com ?
Hey guys - old thread, but was poking about and came across this.  I'll assume you've fix this, but the reason for the behavior (in case others find this) is that Postfix's default configuration requires a FQHN at HELO.  This helps with spam and reverse DNS.  If you want to turn this behavior off, then change this line in main.cf from:
[smtpd_helo_restrictions = reject_non_fqdn_helo_hostname reject_invalid_helo_hostname]
To:
[smtpd_helo_restrictions = reject_invalid_helo_hostname]
Personally, I do NOT like changing this.  However, mail clients on Windows (Outlook, OE and maybe others) pull the hostname off the TCP/IP stack.  So if your machine is named FOO, even if you have a domain suffix of "bar.com" which is forced, or if you force it in the "Computer Name" tab with the "More" button, Win7 will only send FOO to Outlook or OE which is sloppy.  RFC1123 states you MUST send FQHN, but MSFT doesn't allways care about RFC.  And actually, it is a lack of communication between OS and Apps.
Many people have asked how to force Outlook to send the FQHN.  This is a misnomer as it is the OS that sends it.  Regardless, once can force the hostname by editing the registry.  Note this regards the TCP/IP parameters only.  These two values can be changed:
In [HKEY_LOCAL_MACHINE\SYSTEM\ControlSet\services\Tcpip\Parameters]
For the [Hostname] value, you would change [FOO] to [foo.bar.com]
Likewise for the [NV Hostname] value, you would change [FOO] to [foo.bar.com]
If you have many systems, you could always write a .reg file to do it for you.
In this way, you can leave your server more secure and provide functionality to your Windows clients.
Hope this helps.
t