Problem Statement
================
The server test01 and test02 are in cluster . The customer was having concern that they were not able to reach the Cluster-IP through port number 25 .
Analysis and understanding the exact problem
======================================
1. First we validated if the sendmail services are running fine .it was working fine .
2. We tried to telnet the Cluster-IP using port number 25 ,it was rejecting . we tried to telnet all the configured IP’s on the network interfaces using port number 25 but that also failed .
3. We tried to telnet the localhost using port 25 , it was successful . That means that there is no port level blocking at server level .
4. We validated the sendmail configuration file to check for the relay server configuration and found it is ok .
5. Now the question arises that if port is open and we are able to do telnet to localhost ,then why are we not able to do for other-IP . why is the sendmail services listening only to localhost . This was the actual Issue that need to be sorted out .
For searching the solution ,we went through net and found some useful documents . sharing the same .
For sendmail :
============
https://www.novell.com/support/kb/doc.php?id=7003912
After performing this change in configuration file , it was working fine for all the IP's.
For postfix
==========
1. Open /etc/postfix/main.cf file:
# vi /etc/postfix/main.cf
2. Append / modify line as follows to bind to localhost (127.0.0.1) only:
inet_interfaces = 127.0.0.1
3. If you need to bind to 127.0.0.1 and 192.168.2.1, enter:
inet_interfaces = 192.168.2.1,127.0.0.1
Save and close the file. You need to stop and start Postfix when this parameter changes. So type the following to restart Postfix:
# /etc/init.d/postfix restart
================
The server test01 and test02 are in cluster . The customer was having concern that they were not able to reach the Cluster-IP through port number 25 .
Analysis and understanding the exact problem
======================================
1. First we validated if the sendmail services are running fine .it was working fine .
2. We tried to telnet the Cluster-IP using port number 25 ,it was rejecting . we tried to telnet all the configured IP’s on the network interfaces using port number 25 but that also failed .
3. We tried to telnet the localhost using port 25 , it was successful . That means that there is no port level blocking at server level .
4. We validated the sendmail configuration file to check for the relay server configuration and found it is ok .
5. Now the question arises that if port is open and we are able to do telnet to localhost ,then why are we not able to do for other-IP . why is the sendmail services listening only to localhost . This was the actual Issue that need to be sorted out .
For searching the solution ,we went through net and found some useful documents . sharing the same .
For sendmail :
============
https://www.novell.com/support/kb/doc.php?id=7003912
After performing this change in configuration file , it was working fine for all the IP's.
For postfix
==========
1. Open /etc/postfix/main.cf file:
# vi /etc/postfix/main.cf
2. Append / modify line as follows to bind to localhost (127.0.0.1) only:
inet_interfaces = 127.0.0.1
3. If you need to bind to 127.0.0.1 and 192.168.2.1, enter:
inet_interfaces = 192.168.2.1,127.0.0.1
Save and close the file. You need to stop and start Postfix when this parameter changes. So type the following to restart Postfix:
# /etc/init.d/postfix restart
