In the exim.conf, it says:
# If you want to accept mail addressed to your host's literal IP address, for
# example, mail addressed to "user@[111.111.111.111]", then uncomment the
# following line, or supply the literal domain(s) as part of "local_domains"
# above.

# local_domains_include_host_literals
I have searched some sample configurations. Most of the people setting this as:
local_domains_include_host_literals = true

But it returns a syntax error in my server.

any ideas. I am kinda new to linux and exim :o

Thanks

Try just uncommenting the line.

but what happens if you have multiple domains using the same IP on a server? how will the mail system determine who receives the mail if its look at the IP only