Our scenario consists of E2K3/E2K7 coexistence.There are 3 offline address lists which are inherited from Exchange 2003, which only includes the default GAL. Client support is for all versions v2, v3 & v4. Now the point here is, Generation server for the OABs here is an E2K3 server, thereby the default mechanism is public folder & not web-basedDP allow clients to download an OAB. Web-based distribution uses virtual directories while PF distribution uses Exchange PFs.PF distribution is required for clients older than OL2003 SP2.Given that there would be one default OAB enabled & that it can either be web-based distributed or PF-distributed, which one is the best practice for us? We need seamless coexistence & transition & intend to support OL2000, OL2003 & OL2007.Shall we need to go for a new OAB & set the generation server to E2K7 mailbox server & enable the distribution mechanism to both web-based & public folder - to support all outlook clients & transition approach?Observations:I observed - OL2003/OL2007 while connecting to E2K3/E2K7 mailbox download the OAB perfectly with the exception - OL2007 user connecting to E2K7 mailbox via outlook anywhere result into failure of OAB (error 0x8004010f - meaning MAPI_E_NOT_FOUND), though OAB download via MAPI is successfulwhen insalled the first e2K7 MBX server in the E2K3 org, got the following warning:If outlook web access is in use, you should replicate the free/busy folder on thisserver to every other free/busy servers in the organization. This step should be performed once setup completes.read this: http://blogs.msdn.com/dgoldman/archive/2006/08/25/How-Exchange-2007-OAB-Files-are-replicated-to-a-Client-Access-Server-for-download.aspxplease clairify. Thanks in advance. Harry

Our scenario consists of E2K3/E2K7 coexistence.There are 3 offline address lists which are inherited from Exchange 2003, which only includes the default GAL. Client support is for all versions v2, v3 & v4. Now the point here is, Generation server for the OABs here is an E2K3 server, thereby the default mechanism is public folder & not web-basedDP allow clients to download an OAB. Web-based distribution uses virtual directories while PF distribution uses Exchange PFs.PF distribution is required for clients older than OL2003 SP2.Given that there would be one default OAB enabled & that it can either be web-based distributed or PF-distributed, which one is the best practice for us? We need seamless coexistence & transition & intend to support OL2000, OL2003 & OL2007.Shall we need to go for a new OAB & set the generation server to E2K7 mailbox server & enable the distribution mechanism to both web-based & public folder - to support all outlook clients & transition approach?Observations:I observed - OL2003/OL2007 while connecting to E2K3/E2K7 mailbox download the OAB perfectly with the exception - OL2007 user connecting to E2K7 mailbox via outlook anywhere result into failure of OAB (error 0x8004010f - meaning MAPI_E_NOT_FOUND), though OAB download via MAPI is successfulwhen insalled the first e2K7 MBX server in the E2K3 org, got the following warning:If outlook web access is in use, you should replicate the free/busy folder on thisserver to every other free/busy servers in the organization. This step should be performed once setup completes.read this:http://blogs.msdn.com/dgoldman/archive/2006/08/25/How-Exchange-2007-OAB-Files-are-replicated-to-a-Client-Access-Server-for-download.aspxplease clairify. Thanks in advance. Harry

Hi,As we all known, there have three OAB versions:OAB version 2 that is used by Outlook 97, 98 or laterOAB version 3 that is used by Outlook 2003 or laterOAB version 4 that is used by Outlook 2003 SP2, Outlook 2007 or later.Public Folder support all the OAB version to be downloaded by the clients. But web-based distribution is only function for Outlook 2007.From this point, the Public Folder is the best practice.However,we can choose to use both Public Folder Distribution and Web-based Distribution of OABs in Exchange 2007.That way, older clients can still access their OABs using Public Folders.Additionally, the new distribution mechanism has several advantage, the detailed information you can refer to the below article:http://technet.microsoft.com/en-us/library/cc546700.aspxFor the error 0x8004010f, did you try Outlook 2003 to connect Exchange by using Outlook Anywhere?Now please right click the Outlook icon, select Test E-mail Autoconfiguration, check and post the information.You can also try the web tool to verify the this issue: http://www.testexchangeconnectivity.com/ThanksAllen