Hello again List, I hope I can bother you again for an issue we have been noticing. Occasionally, we will see random 550 bounces when resolving aliases stored in LDAP. I have used postmap -q to verify the alias on each of our 3 Postfix mail relays and it resolves correctly. Our architecture is as follows:
Perimeter mail relays --> Load Balancer --> 3 Postfix mail relays A message comes in via the perimeter mail relays, and then is passed to one of the 3 Postfix mail relays via the Load Balancer (Cisco device). Some of our virtual domains are stored locally in BDB and another is stored in LDAP. The config. is as follows: virtual_alias_domains = $config_directory/conf/virt-domains virtual_alias_maps = proxy:ldap:$config_directory/conf/ldap-config.cf hash:$config_directory/virtual The final delivery address is an Exchange 2010 server. The issue we have been experiencing is that when resolving a LDAP alias, it will occasionally result in bounced messages with a 550 error. Strangely though, this happens to only a very small number of aliases. In cases where this occurs, I checked the LDAP server logs and noticed that Postfix does not send a search query to LDAP; in successful cases the search query is sent. The Postfix logs do not show anything regarding the bounce either, the perimeter mail relays and the client simply receive a "550 5.1.1 <e-mail.alias@domain>: Recipient address rejected: User unknown (in reply to RCPT TO command); We are running Postfix 2.6.6 on RedHat Enterprise Linux 6.3. Any ideas if this is a known issue with this version -- perhaps issues with the LDAP libraries or something else? Thanks again in advance for any suggestions. Kind regards, VM
