Originally posted by: SystemAdmin

We are having an issue where sendmail wants to do a DNS lookup for external MX records, even though we are forwarding all mail to a smart host.

If we point the server to a DNS server that does not have forwareds set to allow lookups the mail fails.

I am the DNS admin, not an AIX admin, and am trying to work with our people to get this fixed.

We do not want all of of DNS servers to resolve external addresses.

Thanks!

Originally posted by: tony.evans

Which version of sendmail?

v8 or above may use service.switch to stop DNS lookups,

Create a file called /etc/mail/service.switch with

hosts files
aliases files

in it. Then modify sendmail.cf to use service.switch,

This line is probably commented out in sendmail.cf

#O ServiceSwitchFile=/etc/mail/service.switch

In earlier versions, you need to use the ResolverOptions directive I think,

http://www.ussg.iu.edu/usail/mail/op/op-sh-4.9.html
and
http://wwwcgi.rdg.ac.uk:8081/cgi-bin/cgiwrap/wsi14/poplog/man/3RESOLV/resolver

Were the best references I could find.

basically,

O ResolverOptions=-DNSRCH

may do what you want. But you'd be better off asking this query in a sendmail forum (they'll tell you the version of sendmail on AIX is out of date probably).

Note: I'm not a sendmail expert by any means.

Message was edited by: tony.evans