Enable/Disable DNS Queries for MSF and SMTP to Allow Blind Forwarding All E-Mail Directly to External Mail Server

By default, both MSF (Mail Server Framework) and SMTP (Simple Mail Transfer Protocol) use a DNS query of the domain of the target e-mail to determine further actions to be taken. The DNS queries are unnecessary if all e-mail is simply being forwarded to a remote mail server for handling. PTFs have been released that allow the unnecessary processing and DNS queries by both MSF and SMTP to be shut off. The following PTFs (for product TC1) or the PTFs superseding them for supported releases are as follows:

o V7R1: SI45552 and SI46193
o V6R1: SI44755 and SI45258
o V5R4: SI47744 and SI47241

Once the latest version of these PTFs is applied, you can reference the cover letters to enable the function (enabling the function shutoffs using the DNS queries).

An example from the V6R1 PTF (SI44755 Product 5761-TC1) cover letter follows:

*************************
* Enable this function  *
*************************
1) Stop SMTP and MSF service
ENDMSF
ENDTCPSVR *SMTP

2) Open the function and set the mail router and firewall
a. If enable this function first time, a system scope environment
variable should be created for switch:
ADDENVVAR ENVVAR(QIBM_SMTP_FWDSVR_LCL_MAIL) VALUE('YES')
LEVEL(*SYS)
If the environment variable has been created, change its value
to *YES:
CHGENVVAR ENVVAR(QIBM_SMTP_FWDSVR_LCL_MAIL) VALUE('YES')
LEVEL(*SYS)
b. Run CHGSMTPA to set "Forwarding mailhub server" if not already defined.

3) Start SMTP and MSF service
STRMSF
STRTCPSVR *SMTP

Note- If the system is configured to receive email as an SMTP server this function will cause all email to not get delivered to users mail boxes but instead route the email directly to the router. Do not use this if you are receiving mail on the IBMi

*************************
In the event it is desired to reconfigure SMTP and start sending e-mails out directly (no longer using a remote mail server), it would be necessary to disable this function (which would turn back on DNS queries). Again, from the V6R1 PTF cover letter, the steps to disable are provided:

*************************
* Disable this function *
*************************
1) Stop SMTP and MSF service
ENDMSF
ENDTCPSVR *SMTP

2) Close the function
CHGENVVAR ENVVAR(QIBM_SMTP_FWDSVR_LCL_MAIL) VALUE('NO')
LEVEL(*SYS)
As for "Forwarding mailhub server" configuration, it can be kept
or disabled based on the requirement.

3) Start SMTP and MSF service
STRMSF
STRTCPSVR *SMTP

Note: There are also some additional notes provided in the cover letter covering other unique considerations that should be reviewed.