Hi Adrian,
Q:
I have 2 lotus notes servers. Is it possible on the ESA to add these two servers on the SMTP routes while using the same domain name?
A:
Yes. Please use SMTP Routes option, under Network > SMTP Routes.
Q:
How will the ESA forward incoming mail then? Some sort of load balancing, or will it be a priority thing?
A:Whenever the appliance accept the connection and the message from the sender host, it will check the destination domain of the recipients and look up for SMTP route to reach that destination domain. If there is a SMTP route the appliance will then use the information configured on how to reach the destination. If you have version 7.x of the AsynOS which allows priorization, then the appliance will follow the configuration. If both destiantion servers configured have the same priority, round-robin fashion will be applied.
If you are running a version prior of AsyncOS 7.x then the appliance will connect to the first server configured. If that server is unreachable then it will try the next one configured.
SMTP Routes Overview
SMTP Routes allow you to redirect all email for a particular domain to a different mail exchange (MX) host. For example, you could make a mapping from example.com to groupware.example.com. This mapping causes any email with @example.com in the Envelope Recipient address to go instead to groupware.example.com. The system performs an “MX” lookup on groupware.example.com, and then performs an “A” lookup on the host, just like a normal email delivery. This alternate MX host does not need to be listed in DNS MX records and it does not even need to be a member of the domain whose email is being redirected. The Cisco IronPort AsyncOS operating system allows up to forty thousand (40,000) SMTP Route mappings to be configured for your Cisco IronPort appliance. (See
SMTP Routes Limits.)
This feature also allows host “globbing.” If you specify a partial domain, such as .example.com, then any domain ending in example.com matches the entry. For instance, fred@foo.example.com and wilma@bar.example.com both match the mapping.
If a host is not found in the SMTP Routes table, an MX lookup is performed using DNS. The result is not re-checked against the SMTP Routes table. If the DNS MX entry for foo.domain is bar.domain, any email sent to foo.domain is delivered to the host bar.domain. If you create a mapping for bar.domain to some other host, email addressed to foo.domain is not affected.
In other words, recursive entries are not followed. If there is an entry for a.domain to redirect to b.domain, and a subsequent entry to redirect email for b.domain to a.domain, a mail loop will not be created. In this case, email addressed to a.domain will be delivered to the MX host specified by b.domain, and conversely email addressed to b.domain will be delivered to the MX host specified by a.domain.
"The SMTP Routes table is read from the top down for every email delivery. The most specific entry that matches a mapping wins. For example, if there are mappings for both host1.example.com and .example.com in the SMTP Routes table, the entry for host1.example.com will be used because it is the more specific entry — even if it appears after the less specific .example.com entry. Otherwise, the system performs a regular MX lookup on the domain of the Envelope Recipient."
From our documentation:
"A receiving domain can have multiple destination hosts, each assigned a priority number, much like an MX record. The destination host with the lowest number identifies as the primary destination host for the receiving domain. Other destination hosts listed will be used as backup.
I hope this helps.
Cheers,
Valter
