Step 1: Setting up server-to-server communications

Define the source and the target replication servers to each other. When you define servers, you can also specify Secure Sockets Layer (SSL) communications.

About this task

Server definitions are required for the source replication server to communicate with the target replication server and for the target replication server to report status to the source replication server.

Before you begin this procedure, complete the following prerequisites:

Ensure that the target replication server is accessible from the source replication server with an IP connection.
Ensure that there is enough network bandwidth to accommodate the volume of data to be replicated. If bandwidth is insufficient and the flow of data is impeded, the ability to keep the two servers synchronized is affected.
If you plan to use SSL communication, the SSL infrastructure must be in place on the source and target replication servers. Required SSL certificates must be in the key database file that belongs to each server.

Important: You can specify only one target replication server for a source replication server. However, you can specify one or more source replication servers for a single target replication server. Source and target replication servers must be V6.3 or later.

The method that you use to set up servers depends on whether the server definitions exist and on whether you are using the cross-define function to automatically define one server to another.

To use TLS 1.2, you must specify the SSLTLS12 YES server option in the server options file. If you want to ensure that a minimum TLS protocol level of 1.2 is enforced, set the SSLDISABLELEGACYtls server option to YES. For successful TLS communication, the target server must also be configured to use TLS 1.2.

Procedure

To set up server-to-server communications, complete one of the following actions:

If server definitions do not exist and you want to cross-define servers, complete the following steps:
1. On the target replication server, issue the following commands:
```
set servername target_server_name
set serverpassword target_server_password
set serverhladdress _target_server_ip_address
set serverlladdress target_server_tcp_port
set crossdefine on
```
  Remember: If you want an SSL connection, the value for the SET SERVERLLADDRESS command on the target replication server must be an SSL port. The value of the SET SERVERNAME command must match the server name in the server definition.
2. On the source replication server, issue the following commands:
```
set servername source_server_name
set serverpassword source_server_password
set serverhladdress source_server_ip_address
set serverlladdress source_server_tcp_port
```
  Remember: If you want an SSL connection, the value for the SET SERVERLLADDRESS command on the source replication server must be an SSL port. The value of the SET SERVERNAME command must match the server name in the server definition.
3. On the source replication server connect to the target replication server by using the DEFINE SERVER command. If you want an SSL connection, specify SSL=YES. For example:
```
define server target_server_name hladdress=target_sever_ip_address
lladdress=target_server_tcp_port serverpassword=
target_server_password crossdefine=yes ssl=yes
```
  A server definition is created on the source replication server, and the source replication server is connected to the target replication server. A definition for the target replication server is created that points to the source replication server.
If server definitions do not exist and you are not using the cross-define function, complete the following steps:
1. Issue the following commands on both the source and target replication servers:
```
set servername server_name
set serverpassword server_password
set serverhladdress ip_address
set serverlladdress tcp_port
```
  Remember: If you want an SSL connection, the value for the SET SERVERLLADDRESS command on the replication servers must be an SSL port. The value of the SET SERVERNAME command must match the server name in the server definition.
2. Issue the DEFINE SERVER command on each server. Do not specify the CROSSDEFINE parameter. If you want an SSL connection, specify SSL=YES. For example:
  - On the source replication server:
```
define server target_server_name hladdress=target_server_ip_address
lladdress=target_server_tcp_port serverpassword=target_server_password
ssl=yes
```
  - On the target replication server:
```
define server source_server_name hladdress=source_server_ip_address
lladdress=source_server_tcp_port serverpassword=source_server_password
ssl=yes
```
If definitions exist for both the source and target replication servers, issue the UPDATE SERVER command on each server. Do not specify the CROSSDEFINE parameter. You can use the QUERY STATUS command to determine the server names. If you want an SSL connection, specify SSL=YES. For example:
- On the source replication server:
```
update server target_server_name hla=target_server_ip_address 
lladdress=target_server_tcp_port serverpassword=target_server_password
ssl=yes
```
- On the target replication server:
```
update server source_server_name hladdress=source_server_ip_address
lladdress=source_server_tcp_port serverpassword=
source_server_password 
ssl=yes
```