google mx records
@ or leave blank 3600 MX 1 ASPMX.L.GOOGLE.COM
@ or leave blank 3600 MX 5 ALT1.ASPMX.L.GOOGLE.COM
@ or leave blank 3600 MX 5 ALT2.ASPMX.L.GOOGLE.COM
@ or leave blank 3600 MX 10 ALT3.ASPMX.L.GOOGLE.COM
@ or leave blank 3600 MX 10 ALT4.ASPMX.L.GOOGLE.COM