As of Monday, 31-Mar-2003, AOL's mailservers are now rejecting incoming
SMTP connections from my mailserver, when my mailserver tries to connect
via my Roadrunner cablemodem to send an email to an aol.com address.
They produce the following cryptic SMTP error:
SMTP error from remote mailer after initial connection:
host mailin-04.mx.aol.com [64.12.136.153]:
550-The IP address you're using to connect to AOL is either open to the
550-free relaying of e-mail, is serving as an open proxy, or is a dynamic
550-(residential) IP address. AOL cannot accept further e-mail
550-transactions from your server until either your server is closed to free
550-relaying/proxy, or your ISP removes your IP address from their list of
550-dynamic IP addresses. For additional information, please visit
550
http://postmaster.info.aol.com.
According to the following article, Time-Warner AOL has configured
their mailservers to reject SMTP connections from Time-Warner
Roadrunner cablemodem customers, supposedly as an anti-spam measure:
http://news.com.com/2100-1024-994992.html
So, I need to configure Exim to handle AOL recipients specially
when sending email over the cablemodem connection to aol.com
recipient addresses. Those emails, when sent out over the
cablemodem connection, should be relayed through the local T-W
Roadrunner mailservers, instead of being sent directly to AOL's
mailservers.
However, it gets worse. My little server is dual-homed, for
redundancy (because neither the DSL nor the cablemodem are
especially reliable). I have both a T-W Roadrunner cablemodem
(with dynamic IP) and DSL (with static IP). The default route
out to the 'net is whichever line has been up the longest.
(I have scripts running to test & adjust my routing tables
and DNS when either other service goes down.)
Note that I can't relay email out over the DSL provider's line
to the T-W Roadrunner mailservers, nor can I relay email out
over the T-W Roadrunner line to the DSL provider's mailservers.
So for AOL recipients, the receiving mailserver MUST be adjusted
according to which line I'm using for the connection, DSL or
cablemodem.
So, I want to configure Exim to:
- Continue to send emails to non-AOL addresses directly to the
recipient's mailserver, just as it does now, regardless of
which line is used, DSL or cablemodem; and
- Continue to send emails to all addresses, including AOL
addresses, directly to the recipient's mailserver, just as
it does now, when sending via the DSL line; but
- Send emails to AOL addresses via relay through Roadrunner's
local mailservers, when sending via the cablemodem line.
Note, too, that the decision about which mailserver Exim should
connect to needs to be made all over again each time it attempts
a connection retry, because the routing table could have changed,
which means that a connection retry might try to use the other
line, and thus would need to be sent to a different mailserver.
This seems hard! I don't even know where to start to configure
Exim to do this. Advice, please?
(My temporary workaround is just to force the use of the DSL
connection when sending email to AOL users.)
BTW, I'm currently running Exim 3.36 (because it works, and
because it matches the book). But I can upgrade to Exim 4 if
necessary -- I was planning on doing so anyhow, when I get the
new book.
Thanks in advance!
-Dave
