Gmail, SPF, and broken Email Forwarding
A user posted the following on slashdot.org:
"Background: Like many people, I have me@mydomain.com as my public facing Email address. When Email comes into my server, I forward it to me@gmail.com. But since my friend has published SPF (Sender Policy Framework) records that say only his server is allowed to send Emails for friend@frienddomain.com, gmail apparently rejects (silently buries actually!) the Email since it is forwarding through my server. Please note that this is exactly what SPF is designed to prevent — spammers from sending Emails with your address — but it breaks forwarding and has other problems.
What's *really* strange is that if I look at the raw sendmail logs on my server, the Email from friend@frienddomain.com comes in, and is forwarded to gmail ... with an "OK" as the response — i.e. the gmail MTA doesn't reject the message as it ideally should. However, the Email then disappears — it's not even in my gmail spam filter ... so there is no trace of it at all. If my friend sends directly to me@gmail.com, it shows up ... since his domain sends directly and the SPF test is passed. Note that on my gmail account, I associate me@mydomain.com with my me@gmail.com account ... so perhaps there should be a recipient test applied before SPF is tested on the sender ... although this arguably defeats the purpose of SPF.
The logical solution is to configure sendmail on my server to do Sender Rewriting — anyone have an easy FAQ to do this? But many people/domains aren't doing this ... and my Email forwarding to gmail is quite common, so I'm surprised that this issue hasn't gotten more attention. Is there another solution?"
http://ask.slashdot.org/article.pl?no_d2=1&sid=08/07/10/192240
"Background: Like many people, I have me@mydomain.com as my public facing Email address. When Email comes into my server, I forward it to me@gmail.com. But since my friend has published SPF (Sender Policy Framework) records that say only his server is allowed to send Emails for friend@frienddomain.com, gmail apparently rejects (silently buries actually!) the Email since it is forwarding through my server. Please note that this is exactly what SPF is designed to prevent — spammers from sending Emails with your address — but it breaks forwarding and has other problems.
What's *really* strange is that if I look at the raw sendmail logs on my server, the Email from friend@frienddomain.com comes in, and is forwarded to gmail ... with an "OK" as the response — i.e. the gmail MTA doesn't reject the message as it ideally should. However, the Email then disappears — it's not even in my gmail spam filter ... so there is no trace of it at all. If my friend sends directly to me@gmail.com, it shows up ... since his domain sends directly and the SPF test is passed. Note that on my gmail account, I associate me@mydomain.com with my me@gmail.com account ... so perhaps there should be a recipient test applied before SPF is tested on the sender ... although this arguably defeats the purpose of SPF.
The logical solution is to configure sendmail on my server to do Sender Rewriting — anyone have an easy FAQ to do this? But many people/domains aren't doing this ... and my Email forwarding to gmail is quite common, so I'm surprised that this issue hasn't gotten more attention. Is there another solution?"
http://ask.slashdot.org/article.pl?no_d2=1&sid=08/07/10/192240
Comments