Transport next hops can have MX lookups disabled by adding [] around the next hop.
Is it possible to define a transport that always has MX lookups disabled without specifying the next hop? man 5 transport says that trivial-rewrite(8) doesn't allow substitutions in pcre tables, otherwise, this is what I'd want: /(.+\.internal)/ internal_smtp:[$1] So is there any other way to disable MX lookups wholesale for a given transport? It'd be nice to do something like this: .internal internal_smtp:[] Or a hack for trivial-rewrite that allows pcre substitutions in transport tables (if some security issue arises, maybe the use of substitutions can be restricted in some way?)