> My guess is that LDAP queries are cost even more than than SMTP RCPT > TO "queries".
Checking via RCPT against mail server that in turn validates every recipient against an LDAP server will obviously be slower, usually many times slower, than checking against that same LDAP server directly, provided persistent LDAP connections are used in both cases. Checking via RCPT against a mail server that validates using LDAP and keeps a local cache of LDAP lookups will still be slower than checking against the LDAP server directly; how much slower depends on the sizing of the mailbox server and the performance of its local cache vs. a properly indexed, cached, and sized LDAP server. Checking via RCPT against a mail server that has a fully standalone userbase will be slower than checking via a properly deployed LDAP server with the same database size, unless the RCPT client is able to hold open a persistent SMTP connection for validation. In all cases, as already pointed out, direct LDAP validation places zero load on the mailbox server, which eases that concern completely. It's trivial to forge a configuration in which RCPT appears to be faster than LDAP due to forced disparities in local vs. remote performance... likewise, it's trivial to deploy LDAP so that it so far outstrips RCPT as to be comical. The question is whether you can make a generalized comparison at all, given the range of LDAP client validation and caching techniques; the very wide gaps in performance between different LDAP server implementations; and the unfortunate fact that a given LDAP validating client might not work with a given LDAP server at all (due to authentication and/or schema incompatibility). But speaking as an LDAP developer, if one must generalize, LDAP is the winner. --Sandy ------------------------------------ Sanford Whiteman, Chief Technologist Broadleaf Systems, a division of Cypress Integrated Systems, Inc. e-mail: [EMAIL PROTECTED] SpamAssassin plugs into Declude! http://www.imprimia.com/products/software/freeutils/SPAMC32/download/release/ Defuse Dictionary Attacks: Turn Exchange or IMail mailboxes into IMail Aliases! http://www.imprimia.com/products/software/freeutils/exchange2aliases/download/release/ http://www.imprimia.com/products/software/freeutils/ldap2aliases/download/release/ To Unsubscribe: http://www.ipswitch.com/support/mailing-lists.html List Archive: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ Knowledge Base/FAQ: http://www.ipswitch.com/support/IMail/
