How can I arrange that messages larger than some limit are handled by a special router?

Can I specify a list of domains to explicitly reject?

How can I arrange to do my own qualification of non-fully-qualified domains, and then pass them on to the next router?

Every system has a nobody account under which httpd etc run. I would like to know how to restrict mail which comes from that account to users on that host only.

How can I get Exim to deliver to me locally and everyone else at the same domain via SMTP to the MX record specified host?

How can I get Exim to deliver certain domains to a different SMTP port on my local host?

Why does Exim lower-case the local-part of a non-local domain when routing?

I can't get a lookup to work in a domain list. I'm trying this:

domainlist local_domains = @:localhost:${lookup pgsql{SELECT ...

How do I look up multiple LDAP DNs with query-style lookups?