Google Outbound Services Configuration Guide - Manual (Page 106)

IBM Lotus Domino (Private DNS Method) 113
4. In the nslookup prompt, type gmail.com and hit return to get the gmail.com IP
address.
5. In the nslookup prompt, type server [IP address] and hit return. For
instance, if you are on system 8, type server 64.18.7.12 and hit return. If
you are using a different system number, use the appropriate IP address for
that system.
6. In the nslookup prompt, type gmail.com again. You should see a different IP
address now. If you see an error message, your network settings are blocking
your DNS connection.
7. In the nslookup prompt, type server [old default server] to restore your
default server. Substitute your previous default server name for [old default
server] .
8. Press Control-C to exit nslookup.