On 9 May 2004 at 0:03, Maykel Moya wrote about
"[Exim] Relaxing DNS checks":
| Exim DNS checks are very restrictive. I just need to ensure that an A
| record exists for the incoming ip. How can I achieve that ?
I'm not sure why you want to, but:
1. Test $sender_host_name. If it is set to a value, an rDNS lookup
of the IP address provided a name that owns an A record for the
incoming IP, and your test is satisfied.
${if !eq {$sender_host_name} {}{yes}fail}
If $sender_host_name is not set, there was no PTR record for the IP
address or the PTR name did not own a matching A record. In that
case, you have no way of knowing what domain names may own A records
with the incoming IP, so you have to guess:
2. Try the only name you've got, $sender_helo_name. If it is set,
check for a matching A record:
${if eq {${lookup dnsdb{a=$sender_helo_name}{$value}fail}}\
{$sender_host_address}{yes}fail}
3. If that test fails, you'll have to write a script that generates
all possible domain names, checking each one for a matching A record.
This may take more time than you'd like...
- Fred
