Hi All,
after whOOle of attempts I post my relay problem here :
is years that I can't send mail with my CentOS because I receive 550 relay not permitted...
note that I have another machine CentOS 7 with the same packages installed that can send mail es.
if I input :
echo "this is the msg" | mail -r example@mail.com -s "subj" to@mail.com
I send mails ( for example I successful sent an email to my real hotmail account )
BUT
with the relay problem machine I receive :
send-mail: RCPT TO:<to@mail.com> (550 relay not permitted)
KINDLY : where can I go to try to solve this relay problem ?
t h a n k s

The SMTP server you are trying to use to relay your mail is refusing to relay it. Either you configure your SMTP server to identify it to the relaying server in the manner the relayer requires or you configure the relayer to accept relays from your domain.

In the bad old days sendmail relayed by default. When spammers took advantage of this to camouflage the source of their messages sendmail switched to non-promiscuous relay by default. Eventually SMTP servers stopped accepting mail from domains that allowed promiscuous relay so no one uses it; it remains as an option for sendmail though.

In addition to what RandomTroll said, please tell us what MTA you're using and how it's configured.

Is it the same setup as on the server that does work? What's different?

Hi All,
first thanks for yours reply,
so when I had tried ALL with postfix I tried to install sendmail and everything go fine at to the first try !
sendmail NUMBER ONE ! maybe now I need some of yours suggestions to check that everything is sure ok ( this is a question )
for notice, always I've tried to install postfix I get only problems and when I left I never understood how my postfix go...
I also successful configured spf1 & DKIM1 now I will configured also DMARK to send my promo mails but I just get an excellent spam score of 9.6 on html but is another story...
So now the question is if You can kindly advise me what I have to check/configure to be sure that my sendmail is ok and sure 100 % and maybe if you understand how block my postfix now that sendmail go fine at the first try.
always thanks
Gio

Yes.

Send a message to another domain, inspect it. If we were all buddies you could send us your sendmail.mc but that's not appropriate for a public forum.


Uninstall it?

1 members found this post helpful.

ok RandomTroll thx,
I will send an email and inspect, if come some doubt I will return,
yes, postfix was removed before install sendmail.
again thx
ciao
Gio