You could also configure postfix to relay outgoing mail through google's mail servers. I've done this with sendmail and it seems possible with postifx: http://www.darryl.cain.com.au/postfix/
You need to lookup SPF records as these allow you to specify what hosts are allowed to send mail on your behalf. In this case you need something like the following added as a TXT record on your domain:
v=spf1 include:_spf.google.com ip4:192.0.2.1 -all
Replace 192.0.2.1 with the external ip of your server.
You might also look up DKIM records, but I'm not familiar enough with GoogleMail to be able to see if they're support there or not.
You could also configure postfix to relay outgoing mail through google's mail servers. I've done this with sendmail and it seems possible with postifx: http://www.darryl.cain.com.au/postfix/
You need to lookup SPF records as these allow you to specify what hosts are allowed to send mail on your behalf. In this case you need something like the following added as a TXT record on your domain:
v=spf1 include:_spf.google.com ip4:192.0.2.1 -all
Replace
192.0.2.1
with the external ip of your server.You might also look up DKIM records, but I'm not familiar enough with GoogleMail to be able to see if they're support there or not.