OT: Ideas as to best way to do this

Peter Farrow peter at farrows.org
Thu Apr 17 10:33:53 IST 2008

Jim Dickenson wrote:
> My company has decided to have Google Apps handle our email. The problem is
> there are some email addresses for our domain that I would like to continue
> to deliver locally.
> The options as I see them are:
> 1 - accept all email on Google Apps and then use nicknames and forward email
> to the various nicknames to addresses on my mail server to be delivered
> locally.
> 2 - receive all email on my server and then use virtusertable and/or
> mailertable to pass the email on to Google Apps, delivering the rest
> locally.
> The downside of 1 is that at best the email is in a trash folder on Google
> Apps as I do not see a way to permanently delete mail with a filter. I can
> forward to a usable place and delete it but not get rid of it completely.
> With option 2 I would not want to have MailScanner process, in any way, the
> mail that is forwarded on to Google Apps, just the email to be delivered
> locally. I do not know if there is a way to use multiple instances of
> sendmail to sort the mail and pass some out to Google and the other onto
> MailScanner and then get delivered locally.
> Ideally I would like to do this with one computer. I could do option 2 with
> a virtual server to do the sorting and then either another virtual or a real
> server, on the same hardware, to deal with the local delivered mail.
> Ideas you all can think of would be greatly appreciated.
Just to let you know, all google servers are hopeless at handling email 
to greylisting systems.

You can expect BIG delays as they don't maintain state on smtp queues.

This is the problem:

A company has its domain and emails handled by google,  a person in the 
company sends an email out through googles system to a remove 
destination that uses greylisting.  The email is temp failed as part of 
the greylisting process, so google mail server tosses the email back 
into their "pot of mail queue".  Later another (probably different) 
google mail server takes this message from the queue and retries, but as 
its now a different server, it gets greylisted again because its from a 
different machine this time.  The mail will finally get delivered when 
either all servers have been around the loop at google, or it randomly 
hits on the same relay to retry again.

Typically we see delays of 5hours plus in some cases with google based 
clients, google are the only sending organisation that has this problem.

Message labs have a similar problem, but I am quite happy to whitelist 
them for now as they are not a source of spam...

As greylisting becomes more popular this will become a huge problem.

Typically a greylisting system admin would whitelist google servers to 
get round their problem, however, as google is in the top 100 list of 
spam sources whitelisting their mail relays is a very bad idea....



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