>> Remote Prefs
Status | Content

Status
This document is a consolidation of information, with draft recommendations.

Content
As University members becomes more mobile and wish to access their mail from different locations using different methods, remote access protocols such as IMAP and POP, as well as web clients such as Cubmail, become increasingly critical.

Unresolved, however is the storage of address book and client configuration information in such a way as to allow interoperability of this data from multiple locations. This document examines the protocols available for use as well as potential backing stores to handle the data.

Protocols

ACAP/IMSP

These are two well intentioned but lightly used protocols designed to store preferences on the network for desktop clients.

ACAP and IMSP are suitable for both user address book and user preferences from select clients.

IMAP

Pine supports the storage of configuration information via IMAP.

IMAP is suitable for both user address book and user preferences from PINE.

LDAP

LDAP can be used to access an enterprise directory for address book information, or to store preferences on the network. For write operations, an SSL LDAP server is required, as otherwise the security model is insufficient. Additionally, a solvable but unaddressed problem involves enabling the LDAP server to properly perform password authentication, whatever that means.

LDAP is suitable for read-only enterprise address book and for user address book and user preferences.

SQL

Turba, the Horde contact manager distributed with IMP, can access address book information via SQL. The format for the data stored within the SQL database has not been adopted by any other client, as desktop clients talking to SQL servers is not a typically desirable situation.

SQL is suitable for both user address book and user preferences when accessed via an intermediary.

Data Storage

~user

Data is written to the user's home directory. This provides an easily accessible and modifiable location, and simplifies clean up when the user's account expires. Theoretically, this implementation could use the same files as PINE, simplifying compatibility.

DBM

DBM is the format used by the current LDAP server to store information. It does not require the overhead of an SQL database, and is otherwise reasonably fast. Data is stored in a centralized location, and must be pruned when a user's account expires.

SQL Database

Data is stored within an Oracle or other vendor server. Data is stored in a centralized location, but must be accessed via SQL, and must be pruned when a user's account expires.

Protocol/Storage Interoperability

~user DBM SQL Database
ACAP/IMSP See note See note See note
LDAP Yes, with custom module Yes Yes
SQL No No Yes

Note: The status of ACAP and IMSP servers is best described as elusive. As such, the working assumption should be that either an existing product can be adapted or a new product written that can support any desired storage mechanism.

Client Interoperability

An important note about interoperability: different clients may use slightly or completely different tags when accessing information via any of these protocols, and as such all "Yes" values are really qualified "Yes", pending investigation into the actual data requested. Depending on the protocol adopted and the preferences supported, it may be possible to write a translator to allow different clients with different tags to use the same underlying data.

ACAP IMAP IMSP LDAP SQL
IMP Yes, with custom module Yes, with custom module Yes, with custom module Yes, possibly with custom module Yes
Mulberry Yes No Yes Yes, for enterprise directory only No
Netscape No No No Yes No
Outlook No No No Yes (?) No
PINE No Yes No Yes, for enterprise directory only No

Recommendation

The easiest solution is to not bother, as nothing works with everything. Failing that, writing files to the user's directory seems to make the most sense, as it offer the greatest potential for interoperability (the only other option for PINE is IMAP, which nothing else supports natively), while simplifying management when the user's account is deleted.

Where possible, the implementation should use PINE's format for storing data, at least for the addressbook. Access should be provided via LDAP, for Netscape and Outlook, and ACAP or IMSP for Mulberry. IMP can use LDAP, or can be modified to access the files directly.