Consider that I am providing SMTP services for several clients and the sender / SMTP domain is mails.mysmtp.com. When client A is using my email infrastructure, he may use from address (from header) as 'info@client1domain.com', same way client B may use an account 'info@client2domain.com'.
My question here is - which domain should have the 'postmaster' or 'abuse' or 'fbl' accounts? My domain or client domain?