topic sendmail relaying problem in Operating System - Linux

sendmail relaying problem

kcpant — Wed, 29 Sep 2004 01:21:36 GMT

hi all,
I have setup a mail server on linux 8.0 using sendmail+mailscanner+clamav and fetchmail. the first question I want to ask is : what is the meaning of the following error msg which I frequently get to my mailer daemon account:

The original message was received at Wed, 29 Sep 2004 11:24:22 +0530
from [192.169.10.1]
with id i8T5s8KD002740
----- The following addresses had permanent fatal errors -----

while talking to smtp.net4india.com.:
>>> DATA
550 relaying to prohibited by administrator
550 5.1.1 ... User unknown
<<< 503 Valid RCPT TO must precede DATA

smtp.net4india.com is the smart host which I use for relaying my outgoing mails.the user name abc & domain may be anything for any outgoing mail and 192.169.10 is my local network.I have an internal mail setup for users , as well as users can send mails outside by using their net4india ID, which relayed out by smart host.
I dont get any complain from my users or outside mail reciever about any delay in mail recieving or about not getting mails, which mean this error is not stopping mails , but I can't understand why it is coming frequently.

the second question is, is it a good&wise decision to migrate a mail service of about 100 users from microsoft exchange to linux based fetchmail+sendmail combination?..you all must have a fair answer on this issue because some of you are very experienced linux mail administrators. ( I've just started using and configuring linux from last 6-7 months, setup some small (10-20 users) mail & proxy servers, and going to design a big & complex server for a client).In my experience, my mail services are working very smoothly, no spams at all in inboxes now...

thanks to you all..

Re: sendmail relaying problem

Steven E. Protter — Wed, 29 Sep 2004 11:35:00 GMT

The relay server is not allowing relay.

>>> DATA
550 relaying to prohibited by administrator
550 5.1.1 ... User unknown

Relay in the relay server must be expicitly authorized in the /etc/mail/access file and access.db file.

spam primarily gets into inboxes because users are careless about who they email to or post their email address to searchable websites.

I'm attaching a script that does sendmail anti spam and sendmail.mc macro for linux. You can also do lots more against spam with sendmail hacks at http://www.sendmail.org

To move your users exchange data to a sendmail/fetchmail system you'll need to export the data from outlook/exchange. I think getting rid of Exchange server is a fine idea. Some of the calendar functionality can be duplicated with squirrelmail http://www.squirrelmail.org . Squirrelmail also provides web based mail and dozens of easy to implment customized add in's that your users will love.

There are some migration tools at http://sourceforge.net

SEP

Re: sendmail relaying problem

kcpant — Thu, 30 Sep 2004 00:23:04 GMT

hi steven,

I 've already mentioned that even this error is coming, I don't get any complain from users about mail transfer.I'm just curious why this error is coming from my relay server (which I use for relaying my outgoing mails). The second thing is , I already got rid of all spams once I've implemented sendmail+mailscanner+clamav combination. So, I don't need any more scripting on my sendmail.mc file.

one more thing I want to tell you all is, the "relaying prohibited" error generally comes against read notification acknowledgment replies, which sent automatically once a mail 's read by reciepient.

thanks

Re: sendmail relaying problem

kcpant — Fri, 25 Feb 2005 06:14:19 GMT

closing thread