Exim routing based on individual email addresses

emailexchangeeximmigrationsmtp

I am trying to migrate individual users, one at a time, from an Exim based mail system to an Exchange 2010 system. I'm hoping to do this by leaving the Exim based system as the MX for the time being, and as a user mailbox is created on the Exchange system, then a manualroute rule is created for that user on the exim system, so that any mail addressed to them from both local and remote senders is delivered to the Exchange mailbox instead.

My experience with Exim is limited, but it appears that the manual routing rules I've seen thus far are domain based, but these addresses (on the Exchange and Exim systems) will have the same domains, so I'm hoping that I can route based on specific email addresses. What would be the best way to go about this?

Best Answer

The Exim Book gives an example of manualroute with user part lookups 5.6.1 Using a manualroute router

Below please find it modified to your needs (based on 7.4 The manualroute router in the book):

exchange_people:
   driver = manualroute
   domains = example.net  ## limit router to addresses in example.net domain
   local_parts = lsearch;/etc/e_users 
   route_list = * exchange.example.net ## send to  exchange.example.net host
   transport = remote_smtp

Related Solutions

Linux – GeoIP based greylisting with Exim

I am answering my own question now that I have a solution that I like myself.

Greylisting itself can be implemented purely with Exim access control lists, or an external greylisting helper can be hooked to the ACLs. There are several approaches to this, which are documented elsewhere.

Greylisting is typically implemented in access control lists, and therefore it is easy to add some external IP address lookup in the ACL to control greylisting behavior (for example to skip greylisting according to a country code lookup).

There are several alternatives for getting the country code:

DNSBL lookup using for example http://countries.nerd.dk/ (as in mailq's answer).
Import some GeoIP database into a SQL database and make a SQL query from the ACL.
Implement GeoIP lookup using one of the several perl GeoIP modules and hook that in the Exim ACL with the perl interface.
Use a dlfunc library which implements the GeoIP lookup in the ACL.

I personally chose the last option as it is most efficient and does not depend on external resources. I implemented a new dlfunc library for this purporse as none of the several existing ones had IPv6 support. My implementation with simple examples is available at: http://dist.epipe.com/exim/. While implementing this I learned about Exim ACLs and found that they are extremely powerful for implementing any kind of mail acceptance policies.

Now it is easy to skip greylisting for certain countries by adding an ACL rule before the greylisting rules:

warn    set acl_c_geoip_country_code = \
        ${dlfunc{/usr/local/lib/exim4/exim-geoipv6-dlfunc.so}\
        {geoip_country_code}{$sender_host_address}}

accept  condition = ${if inlist{$acl_c_geoip_country_code}{FI:SE:EE}}

Exim versions older than 4.77 do not have inlist{ syntax. The same can be achieved by changing the second rule as follows:

accept  condition = ${if forany{FI:SE:EE}{eq{$item}{$acl_c_geoip_country_code}}}

Migrating E-mail from Dovecot/exim4 to Exchange – Large Inbox

You would use a tool like imapsync to transfer mail data directly from the old system to the new Exchange server if you manage or have user-level/administrative access to both systems. Alternatively, if the user is using Outlook, for instance, they can migrate their mail via local export to .PST or simply copy across to the newly-established mail account in the same client.

A better question is whether you need to move all 10GB of messages... It does not sound like you administer the new system...

Best Answer

Related Solutions

Linux – GeoIP based greylisting with Exim

Migrating E-mail from Dovecot/exim4 to Exchange – Large Inbox

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