I'm currently using Google Apps to forward mails addressed to recipients at my domain balkan-preferans.de (18.104.22.168) to my address First.Last@gmail.com - this is done by the following DNS-zone served by my hoster:
$TTL 86400 @ IN SOA ns1.first-ns.de. postmaster.robot.first-ns.de. ( 2012100402 ; serial 14400 ; refresh 1800 ; retry 604800 ; expire 86400 ) ; minimum @ IN NS robotns3.second-ns.com. @ IN NS robotns2.second-ns.de. @ IN NS ns1.first-ns.de. @ IN A 22.214.171.124 localhost IN A 127.0.0.1 www IN A 126.96.36.199 @ IN MX 1 ASPMX.L.GOOGLE.COM. @ IN MX 5 ALT1.ASPMX.L.GOOGLE.COM. @ IN MX 5 ALT2.ASPMX.L.GOOGLE.COM. @ IN MX 10 ASPMX3.GOOGLEMAIL.COM. @ IN MX 10 ASPMX2.GOOGLEMAIL.COM.
This has worked well for the past year, but I'd like to get rid of Google Apps, because they aren't free of cost anymore and I don't use any other features of that product.
So I'd like to change the MX-records above to point to my 2 web servers - which run 24/7 anyway.
On the servers with CentOS 6 Linux I currently run sendmail (for sending logwatch mails mainly).
Could anybody please provide some hints on which macros to add to
/etc/mail/sendmail.mc so that all mail for the balkan-preferans.de is accepted and then relayed to my address First.Last@gmail.com?
Do I have to open an incoming port in iptables firewall too?