topic Not getting mail from outside servers in Operating System - Linux

Not getting mail from outside servers

monu_1 — Sat, 16 Feb 2008 10:23:28 GMT

Hi All,

I have setup sendmail server on fedora6 with dovecot, sqirrelmail web based application.
hostname mail3.abc.net(PTR record set)
ipaddr 192.168.0.4
default gatway 255.255.255.0
nameserver 203.122.63.154

now users can send and receive mails in local environment and can send also outside smtp servers.

But probelm is that no one can received mails from any outside mail servers.

following is the mail delivery report from sender which is outsider-

Delivery to the following recipient has been delayed:

manoj@mail3.abc.net

Message will be retried for 2 more day(s)

Technical details of temporary failure:
TEMP_FAILURE: Could not initiate SMTP conversation with any hosts:
[mail3.abc.net (1): Connection refused]

Please sugget where is missing...?

Thanks in Advanced
MKS

Re: Not getting mail from outside servers

Matti_Kurkela — Sat, 16 Feb 2008 11:36:04 GMT

If 192.168.0.4 is your true IP address, the problem is obvious: Any address in 192.168.*.* range is a "private" or "non-routable" IP address. These addresses are not globally unique: anyone can set up a network using these addresses. So the outsider's system has no way to indicate *which one* of the various "192.168.0.4"s in the world it wants to connect to.

Your outsider's connection is probably reaching some other 192.168.0.4 which is not accepting SMTP traffic, not your server.

There must be a NAT device of some sort in between your network and the global Internet.
That device will make your entire network seem like just one IP address. *That* is the IP address you would have to announce to the world as "mail3.abc.net".

In addition, you would have to set up a "virtual server" or a "destination NAT configuration" to the NAT device, so that any incoming connections to port 25 (SMTP) of the NAT device will be redirected to port 25 of 192.168.0.4.

If the NAT device is in your control, you probably can do this. But if the NAT device is controlled by your Internet Service Provider, there might be a problem: consumer-grade Internet connections may not include a permission to run a mail server, and this is enforced by not setting up redirections like this.

There are alternative ways to arrange the delivery of incoming emails, if your ISP makes some arrangements (mail relaying, suitable MX records in DNS). Contact your ISP for more information.

MK

Re: Not getting mail from outside servers

monu_1 — Sat, 16 Feb 2008 12:29:49 GMT

Thanks matti,

I am using that static IP(mail3.abc.net) for sending mails.
How can it possible to use this server for incomming mails?
I have already configure virtual hosting for that server.

Thanks & Regards,
MKS