[Pkg-exim4-users] exim4, gmail and 550-5.7.1

[Robert Steinmetz AIA]

I run two mail servers one postfix and the other exim4, both on Ubuntu.

Any email to a gmail server is rejected with a 550-5.7.1 error, 
basically requiring a ipv6 ptr record.

I have known about this problem for a while but used other workarounds. 
Recently we have seen more and more people hosting their email on gmail 
using this own domains. So I decided it was time to solve the problem 
permanently. Unfortunately our IP addresses are provided by our ISPs and 
they don't provide ipv6 ptr records.

I solved it with the postfix server by setting up a list of domains to 
be to ipv4 only. That works well and is easy to add more domains as I 
discover them

Is there a comparable method for exim4? Or some other way of overcoming 
the problem? I have Goggled around and the postfix answers came up 
pretty easily, I've found very little on exim4.

I did find this web page:

https://github.com/Exim/exim/wiki/How-to-force-IPv4-connections-for-specific-domains-if-IPv6-is-enabled 


But I'm not sure how to implement it. I can certainly add a Router and 
Transport to the appropriate directory, but where should the domain list 
go under conf.d?