Re: [exim] Spammers ignoring MX

Grant Peel wrote:
> Hi all,
>
> I have a number of domains that the MX is set to an outside spamfiltering server. These domains are still getting spam that is being sent directly to our servers, thus bypassing the spamfiltering.
>
> Now in order for use to accept email from the spamfiltering service, I need to accept mail for that domain.
>
> Is there a was to tell the mailserver to only accept mail for those domains that comes from specific hosts?
>
I wrote an example for our service/customers here
https://www.onlymyemail.com/support/helpful_hints/corporate/sample_exim_configuration.txt

It's pretty basic, might not fit what you're trying to do. If your
dealing with a mix of filtered and not filtered domains on the same
server I'd recomend setting up a domain list with the domains that are
filtered, and then doing the ACL check at RCPT time comparing the
sending host to the host list of your filtering service.

Here's what I use on the server that hosts my vanity domain and a couple
others.

# This access control list is used for every RCPT command in an
# incoming SMTP message.  The tests are run in order until the
# recipient address is either accepted or denied.
acl_rcpt_to:
        # Accept mail received from local sources
        accept  hosts           = : +relay_from_hosts

        # Accept if the message arrived over an authenticated connection,
        # from any host. These messages are usually from MUAs, so
        # recipient verification is omitted.
        accept  authenticated   = *

        # Temporarily reject mail for accounts that are deactivated
        defer   message         = Account disabled, please try again later.
                domains         = +local_domains
                condition       = ${lookup 
mysql{MYSQL_DISABLED_ACCOUNT_QUERY}}

        # If the domain has external filtering accept mail from them
        accept  domains         = +filtered_domains
                hosts           = +filtering_hosts
                verify          = recipient

        # Don't accept mail for filtered domains not from their 
respective filter service
        deny    message         = Please use the public MX server for 
the domain $domain
                domains         = +filtered_domains
                hosts           = !+filtering_hosts

        # Deny local parts with restricted characters
        deny    message         = Restricted characters in address
                domains         = +local_domains:+relay_to_domains
                local_parts     = ^[.] : ^.*[@%!/|]

        deny    message         = Restricted characters in address
                domains         = !+local_domains:!+relay_to_domains
                local_parts     = ^[./|] : ^.*[@%!] : ^.*/\\.\\./

        # Accept mail for local domains, deny unknown users
        accept  domains         = +local_domains
                verify          = recipient
        deny    message         = User unknown: $local_part@$domain
                domains         = +local_domains
                !verify         = recipient
                delay           = 60s

        # Accept mail for domains we relay for, deny if verification fails
        accept  domains         = +relay_to_domains
                verify          = recipient/callout=30s,defer_ok,,use_sender
        deny    message         = $acl_verify_message
                domains         = +relay_to_domains
                delay           = 60s

        # Deny everything else
        defer   message         = Relay prohibited, SMTP authentication 
required

Hope that helps

-Bryan Rawlins
OnlyMyEmail Inc.