| Internet Serice Provider | SMTP Server Name |
| Alltel | mail.alltel.net |
| AltaVista.com | email.1stup.com |
| Ameritech DSL | mailhost.col.ameritech.net |
| AOL | none |
| Aramiska | smtp.aramiska.net |
| AT&T | smtp1.attglobal.net |
| AT&T WorldNet | mailhost.att.net |
| bellatlantic.net | smtpout.bellatlantic.net |
| Big Bear Valley Net | mail.bbv.net |
| Blue Yonder | smtp.blueyonder.co.uk |
| Breathe | mailhost.breathemail.net |
| bright.net | mail.bright.net |
| BT Click | smtp.btclick.com |
| BT Connect | smtp.btconnect.com |
| BT Internet | smtp.btinternet.com |
| BT Openworld | mail.btopenworld.com |
| BT (Broadband) | smtp.btclick.com |
| Business Serve | smtp.businessserve.co.uk/ aap.businessserve.co.uk |
| Cableinet | smtp.blueyonder.co.uk |
| Claranet | relay.clara.net |
| columbia.edu | smtp.cc.clumbia.edu |
| Comcast | mail.comcast.com |
| compaq.net | smtp.compaq.net |
| Compuserve 2000 | smtp.cs.com |
| Compuserve Classic | mail.compuserve.com |
| CWCom | smtp.ntlworld.com |
| Demon | post.demon.co.uk |
| Discover Net | mail.discover.net |
| DreamSoft | mail.dreamsoft.com |
| Easynet | smtp.easynet.co.uk |
| Easypublish | smtp.easypublish.co.uk |
| ECR.net | ecr.net or mail.ecr.net |
| ee.net | mail.ee.net |
| EEE | pop.eee.org |
| Eidosnet | smtp.eidosnet.co.uk |
| EmpireNet | e2.empirenet.com |
| erols.com | smtp.erols.com |
| earthlink.net | mail.earthlink.net |
| Eurobell | mail.eurobell.co.uk |
| Excite@home | mail.comcast.com |
| Farming-On-Line | smtp.farmline.com |
| fast.net | relay.fast.net |
| Free 24-7 | smtp.free24-7.net |
| freei.net | mail.your
two letter state abbreviation.freei.net (eg mail.ny.freei.net) |
| Freeserve | smtp.freeserve.co.uk |
| Freeserve | smtp.freeserve.net |
| Fsnet | smtp.freeserve.co.uk |
| Gateway | smtp.gateway.net |
| Genie | mail.genie.co.uk |
| Global Center | smtp.primenet.net |
| Globalnet | smtpmail.globalnet.co.uk |
| Host Eutope | smtp.hosteurope.com |
| ibm.net | smtp1.ibm.net |
| ic24 | smtp.ic24.net |
| icdc.com | mailout.icdc.com |
| Infinity Internet | smtp.iinet.com |
| Infolink.com | mail.infolink.com |
| Inland Internet | mail.inland.net |
| Interlink | mail.your-net.com |
| Iomart | smtp.domain.extension |
| IronNet | mail.iron.net |
| iwayNET | smtp.iwaynet.net |
| Jade Inc. | mail.jadeinc.com |
| Keyway Internet | mail.keyway.net |
| Lineone | smtp.lineone.net |
| Linkline | mail.linkline.com |
| Local Net | mail.local.net |
| Lycos | smtp.lycos.co.uk |
| Madasafish | smtp.madasafish.com |
| mcgill | po-box.mcgill.ca |
| MidOhio.net | mail.midohio.net |
| mindspring | mail.mindspring.com, mail.earthlink.net |
| Mistral | smtp.mistral.co.uk |
| MSN | smtp.email.msn.com |
| NamesToday | smtp.namestoday.ws |
| netcom.com | smtp.ix.netcom.com |
| netreach.net | smtp.netreach.net |
| Netscapeonline | mailhost.netscapeonline.co.uk |
| NetSet | mail.netset.com |
| NetWalk.com | mail.netwalk.com |
| netzero.net | smtp.netzero.net |
| nextek.net | mail.nextek.net |
| Nildram | smtp.nildram.co.uk |
| nni.com | nni.com |
| Northstar Data Systems | mail.nn.net |
| NTLWorld | smtp.ntlworld.com |
| Onetel | mail.onetel.net.uk |
| On-Ramp | mail.marion.net |
| paonline.com | mail.paonline.com |
| PacBell | mail.pacbell.net |
| PE Net | mail.pe.net |
| Pipex | smtp.dial.pipex.com |
| Plus.net | relay.plus.net |
| Prodigy | smtp.prodigy.net |
| PSI Net | relay.smtp.psi.net |
| Purplenet | smtp.purplenet.co.uk |
| Quadnet | mail.quadnet.net |
| rcn.com | smtp.rcn.com |
| redbird.net | mail.richnet.net |
| RichNet | mail.richnet.net |
| Road Runner (insight) | smtp-server.insight.rr.com |
| Road Runner (Time Warner) | smtp-server.columbus.rr.com |
| rutgers.edu | email.rci.rutgers.edu |
| screaming.net | smtp.tiscali.co.uk |
| Supanet | smtp.supanet.com |
| Talk21 | out.talk21.com |
| Telewest | smtp.blueyonder.co.uk |
| Telocity | mail.telocity.com |
| Tesco | mail.tesco.net |
| Tiscali | smtp.tiscali.co.uk |
| Totalise | mail.totalise.co.uk |
| TST On Ramp | mail.tstonramp.com |
| UK2 | smtp.uk2.net |
| UKGateway | smtp.ukgateway.net |
| uu.net | alterdial.uu.net, mail.uu.net |
| v21 | smtp.v21.co.uk |
| Verizon | smtpout.verizon.net |
| Virgin | smtp.virgin.net |
| Vispa | mail.vispa.com |
| voicenet.com | mail.voicenet.com |
| Waitrose | smtpmail.waitrose.com |
| Wanadoo | smtp.wanadoo.co.uk |
| wcom.net | pop3host.wanmail.net |
| webcom.com | smtp.webcom.com |
| Which? Online | mail.which.net |
| Wight 365 | smtp.wight365.net |
| Worldonline | smtp.tiscali.co.uk |
| Yahoo | smtp.mail.yahoo.com |
| ZX3 | smtp.zx3.net |