2538 (09EA) (RC2538): MQRC_HOST_NOT_AVAILABLE

Explanation

An MQCONN call was issued from a client to connect to a queue manager but the attempt to allocate a conversation to the remote system failed. Common causes of this reason code are:

The listener has not been started on the remote system.
The connection name in the client channel definition is incorrect.
The network is currently unavailable.
A firewall blocking the port, or protocol-specific traffic.
The security call initializing the IBM MQ client is blocked by a security exit on the SVRCONN channel at the server.

Completion code

MQCC_FAILED

Programmer response

Examine the client error log for messages explaining the cause of the problem.

If you are using a Linux server, and receiving a 2538 return code when trying to connect to a queue manager, ensure that you check your internal firewall configuration.

To diagnose the problem, issue the following commands to temporarily turn off the internal Linux firewall :
```
/etc/init.d/iptables save
/etc/init.d/iptables stop
```
To turn the internal Linux firewall back on, issue the command:
```
/etc/init.d/iptables start
```
To permanently turn off the internal Linux firewall, issue the command:
```
chkconfig iptables off
```