UNIX for Dummies Questions & Answers

Hello all,

I have been trying to understand sendmail. I'm having problem sending mail to another machine on the same network. I keep on getting error "Deferred: Name Server :redone: host name lookup fail". I can ping the machine and log in via ssh no problem. I don't have a DNS server. Is this because sendmail is looking for host via the DNS server instead of /etc/hosts. I have edit my /etc/resolv.conf file to not look for a nameserver just the domain. But the same thing. I can mail to a user on the machine locally. I can telnet to the smtp port locally but not from the out side ( another machine). I have edit my /etc/hosts.allow to include the other machine. I have also look at the posting here and edit the sendmail.cf to accept unreolv hostname and account and recompile. This doen't work. I'm lost. I'm currently running redhat AS3. Any help would be great. THANKS

On the machine that is running sendmail, you have to have a number of configuration files right of "there will be dragons."

First, I would insure that the forward and reverse DNS exists in both the /etc/hosts file and the DNS. Sendmail likes DNS, especially itself, to be configured correctly.

Sendmail normally tries to resolve its own hostname, but you can also enter it directly in the .cf file.

There is also a file, often located in /etc/mail/local-host-names which needs to have, of course, the local host names.

You can always post your files and we can have a look!

Neo

Neo,

Here is the set up dell-56 is the DNS server Server23 is a DHCP server. I'm trying to mail betweeen the two. These files are on my dell-56 server. Here are my files. I know that one problem was DNS. I've install a DNS server and now I don't get a responce of could not find hosts.

Now I'm getting connectrion refused by hosts...

Here are my files:

/etc/mail/access

# by default we allow relaying from localhost...
localhost.localdomain RELAY
localhost RELAY
127.0.0.1 RELAY
dell-56 OK
server23 OK
dell-80 OK


/etc/mail/local-hosts-named

# local-host-names - include all aliases for your machine here.
dell-56


/etc/hosts.allow

#
# hosts.allow This file describes the names of the hosts which are
# allowed to use the local INET services, as decided
# by the '/usr/sbin/tcpd' server.
#

ALL:ALL


/etc/mail/sendmail.cf Just a few cut from it


Cwlocalhost
# file containing names of hosts for which we receive email
Fw/etc/mail/local-host-names

# my official domain name
# ... define this only if sendmail cannot automatically determine your domain
#Dj$w.Foo.COM

CP.

# "Smart" relay host (may be null)
DS
# access_db acceptance class
C{Accept}OK RELAY


C{ResOk}OKR


# Hosts for which relaying is permitted ($=R)
FR-o /etc/mail/relay-domains



I hope you can help my. If you need other files let me know.

I just try to telnet to my smtp port and getting connection refused.

[dell-56]> telnet dell-56 25
....Unable to connect to remote host: Connection refuse.

I don't have ipchain or iptables running.


THANKS

OK, let's do this by-the-book, step-by-step:

Please post the output of a command like:

ps -aux | grep sendmail

So first we check if sendmail is running.

Is it?

Yes sendmail is running


root:......:sendmail: accepting connectoions
smmsp... : sendmail: Queue runner@01:00:00