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Relay server

 
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iman_1
Advisor

Relay server

Is it possible to configure the sendmail without any relay server ?

Example : I have 100 unix host servers, A, B, C, D .......

I want email from A to go directly to B without the need of any relay server ? Although there would be one smtp gateway to send and receive emails from outside for the unix hosts.
5 REPLIES
Michal Kapalka (mikap)
Honored Contributor

Re: Relay server

hi,

i think if you make

mailx for examle .... userx@server1(IP)

it should be directly deliver the message.

mikap
Ganesan R
Honored Contributor

Re: Relay server

Hi,

You don't need any relay server to send mails inside your network. Relay server is to send the mails outside.
Best wishes,

Ganesh.
VK2COT
Honored Contributor
Solution

Re: Relay server

Hello,

Of course you can configure Mail Transfer Agent
like sendmail not to use relay hosts.

Here is the behaviour when mailertables are
not in use:

a) If sendmail can find MX- resource records
for a specific domain, then it will try
to deliver messages to the servers listed
as MX.

b) If MX- resource records do not exist, than
A- resource records are looked up and
email delivery tried directly.

As long you have a decent host resolution
setup at your company, it will work fine.

Also, the remote servers must listen on,
typically, SMTP port 25. I have seen some
sites using obscure ports for SMTP.
It does not improve security at all but
obviously makes some people happy thinking
that nobody can figure it out :)

To test where email is supposed to be delivered, here is a simple command:

/usr/lib/sendmail -bv user@mydomain.dom

Cheers,

VK2COT
VK2COT - Dusan Baljevic
Steven E. Protter
Exalted Contributor

Re: Relay server

Shalom,

Yes you don't need a relay server.

The standard sendmail configuration attempts to resolve the target domain with DNS and get the MX record of the domain and send directly.

Port 25 must be open to the outside world.

The reason most corporate environments use relay servers is because the level of preparation necessary to meet public Internet anti spam rules is onerous.

SEP
Steven E Protter
Owner of ISN Corporation
http://isnamerica.com
http://hpuxconsulting.com
Sponsor: http://hpux.ws
Twitter: http://twitter.com/hpuxlinux
Founder http://newdatacloud.com
Vishu
Trusted Contributor

Re: Relay server

Hi iman,

i hope Ganesan and SEP must have cleared your doubt on relay server that they are used to send mail outside the network, to public internet.

So, you can directly send the mails to other hosts, if they are getting resolved properly.

Thanks