connection timeout with smtp server

Issue: 

 I have faced this issue after I did inplace upgrade from OEL 6 to OEL 7. I am not able to send email and the maillog [/var/log/] updated with below error. 

 node-02 sendmail[27436]: 27E5KQWW098928: to=, ctladdr= (1001/1001), delay=00:20:52, xdelay=00:00:00, mailer=esmtp, pri=480584, relay=test.com., dsn=4.0.0, stat=Deferred: Connection timed out with test.com. 

node-02 sendmail[27544]: 27E5eOXd027538: to=, ctladdr= (1001/1001), delay=00:01:00, xdelay=00:01:00, mailer=esmtp, pri=120584, relay=test.com. [192.23.6.77], dsn=4.0.0, stat=Deferred: Connection timed out with test.com.

Reason For this issue: 

In our infra, our mail server dns name is “mail.test.com” and there is separate server for hosting one website called “test.com”. Due to that, If I use “mail.test.com”, The linux server resolves “test.com” instead of “mail.test.com” and ended with timeout error.

Solution: 

Update the IP instead of dns in the configuration. 

• systemctl stop sendmail 

• vi /etc/mail/sendmail.mc 

• Add the below entry [replace the hostname with IP] 

            o define(`SMART_HOST', `192.168.10.111')dnl 

• m4 /etc/mail/sendmail.mc > /etc/mail/sendmail.cf 

• systemctl restart sendmail 

 If the same issue happens, do the below steps and restart sendmail services.

 • grep DS /etc/mail/sendmail.cf 

Sample output: DS192.168.10.111 If there is no IP, add mail server IP.

Oracle Database Appliance [ODA] patching from 18.8.0.0.0 to 19.8.0.0.0 [patch 31481822]

 Oracle Database Appliance [ODA] patching from 18.8.0.0.0 to 19.8.0.0.0 [patch 31481822]

 Pre-requisite:-

1)      Take the backup of ODA_BASE. It is mandatory before proceeding with upgrade process.

2)      Follow Doc ID 1633166.1 to take backup of ODA_BASE server. Else,

a.       Shutdown the oda_base from dom server [oakcli stop oda_base]

b.       Execute the below command. Do not execute it without shutdown oda_base

                                                    i.      tar -cvzf node1.tar.gz /OVS/Repositories/odabaseRepo/VirtualMachines/oakDom1/

c.       Start the oda_base from dom server [oakcli start oda_base]

3)      Perform the same for another ODA_BASE node.

4)      Deregister the ODA_BASE nodes from ULN repository if it is registered. It is mandatory else the ODA_BASE will be corrupted after upgrade and ended with below error in boot screen.

Error 15: File not found

5)      Download the below packages and unpack it.

p31481822_198000_Linux-x86-64_3of3.zip

p31481822_198000_Linux-x86-64_1of3.zip

p31481822_198000_Linux-x86-64_2of3.zip è It is for Database patching. We can download it later.

6)      Keep minimum 7GB of free space in “/” location after unpack all packages.

7)      Execute the below command to unpack the package.

a.       oakcli unpack -package /u01/app/patch/p31481822_198000_Linux-x86-64_1of3.zip

b.       oakcli unpack -package /u01/app/patch/p31481822_198000_Linux-x86-64_3of3.zip

8)      Execute the below command to generate the pre-patch report.

a.       oakcli update -patch 19.8.0.0.0 --pre-patchreport –local

                                                    i.      Check the report  and fix the issues.

                                                   ii.      The report generation only one time and we cannot generate it multiple times if there is no issues and server ready for upgrade

Upgrade ODA_BASE 

9)      Execute the below command

a.       oakcli update -patch 19.8.0.0.0 --pre-patchreport –local

b.    oakcli update -patch 19.8.0.0.0 --pre-osupgrade --local

c.       oakcli update -patch 19.8.0.0.0 --osupgrade –local

d.       Perform above 2 steps in second node and then execute “oakcli update -patch 19.8.0.0.0 --post-osupgrade –local”

After Upgrade completed, execute "uname -a" or "cat /etc/oracle-release" to check the new version. It should be like below,

[root@test-01 patch]# uname -a

Linux test-01 4.14.35-1902.303.4.1.el7uek.x86_64 #2 SMP Fri May 29 14:56:41 PDT 2020 x86_64 x86_64 x86_64 GNU/Linux

[root@test-01 patch]# cat /etc/oracle-release

Oracle Linux Server release 7.8

[root@test-01 patch]#