List of ISPs and the Authentication Methods they use

ISP

Authentication type

AOL (aol.com)

SPF/Sender-ID//DKIM

CompuServe (compuserve.com)

SPF/Sender-ID/

Netscape (netscape.com)

SPF/Sender-ID/

Bellsouth (bellsouth.net)

SPF

Charter (charter.net)

SPF

Comcast (comcast.net)

SPF

Cox (cox.net)

DKIM

Earthlink (earthlink.net, mindspring.com, peoplepc.com)

DomainKeys

Google(gmail.com)

SPF/ DomainKeys /DKIM

Juno/NetZero (juno.com, netzero.net)

SPF/Sender-ID

Microsoft (msn.com, hotmail.com)

SPF/Sender-ID

RoadRunner (rr.com)

SPF

Verizon (verizon.net)

SPF

Yahoo! (yahoo.com)

DomainKeys

SBCGlobal (sbcglobal.net)

DomainKeys

British Telecom (btinternet.com)

DomainKeys

Rogers Cable (rogers.com)

DomainKeys

Rocket Mail (rocketmail.com)

DomainKeys