Very simple thing this: I came across the problem in two different situations so I reckon it's worth a wee mention here...

This guide applies to all email accounts apart from hotmail and yahoo and other purely web based email services. When you type in your email settings to RECEIVE your email, they can remain as they are wherever you are in the world, and you should be able to receive your email with no problem...

The difficulty arrives with sending email. Most emails are sent using SMTP which stands, quite simply, for 'Simple Mail Transfer Protocol'. In order to send mail from any email account you must put in the SMTP address for the PROVIDER you are using to connect to the internet. This is strange because it is really the only setting on your computer that would have to change in order for all your services (internet, ftp, chat programs etc etc) to work as normal.

So, for anyone who has for example recently arrived in a new office or in a halls of residence were your connection to the internet has changed, you may find you can do everything with no problem EXCEPT SEND email from your normal account. All you need do then, is fill in the address of the SMTP server for the system you are on...

At home, your broadband provider will have an SMTP server, at college or work, the network will have a different SMTP server, and a friends house another etc.

Finding the address should be easy (most service providers will provide you with it with or without your request), but I had to spend about half an hour searching on google to find out the the SMTP address for the SWAN network of the University of London (which includes all the halls of residences of course) and is:

senateml.lon.ac.uk

And the following is a list of SMTP servers for some of the main ISPs:

Actrix Networks - mail.actrix.co.nz
AltaVista.com - email.1stup.com
AOL - rly-ip03.mx.aol.com
AOL - rly-ip04.mx.aol.com
AOL - rly-ip05.mx.aol.com
AT&T - smtp1.attglobal.net
AT&T Business Internet - mail.attbi.com
AT&T Worldnet - mailhost.att.net
Bell Atlantic - smtpout.bellatlantic.net
Blazenet - smtp.blazenet.net
BlueYonder - smtp.blueyonder.co.uk
BusinessServe - smtp.businessserve.co.uk
BTClick - smtp.btclick.com
BT Internet - mail.btinternet.com
BT Openworld - mail.btopenworld.com
Cableinet - smtp.blueyonder.co.uk
Charm.net - smtp.charm.net
Claranet - relay.clara.net
ClearNet - smtp.clear.net.nz
Coastalnet - mail2.coastalnet.com
Compuserve - smtp.compuserve.com
Concentric - smtp.concentric.net
CWCom - smtp.ntlworld.com
Bluelight.com - smtp.mail.yahoo.com
Charter - Pipeline - smtp.charter.net
CalWeb - smtp.calweb.com
Comcast - smtp.comcast.net
Compaq.net - smtp.compaq.net
Crosslink - smtp.crosslink.net
CWnet.com - mail.cwnet.com
DCA.net - smtp-relay.dca.net
Demon - post.demon.co.uk
DirectConnect - smtp.directcon.net
Earthlink - smtpauth.earthlink.net
Easynet - smtp.easynet.co.uk
Erols - smtp.erols.com
Fast.net - relay.fast.net
Freeinet.com - mail.ma.freei.net
Freeserve - smtp.freeserve.co.uk
Gateway - smtp.gateway.net
Genie - mail.genie.co.uk
Globe - Net - smtp.globe.net.nz
GTI - mail.gti.net
IBM.net - smtp1.ibm.net
IC24 - smtp.ic24.net
IHUG - smtp.ihug.co.nz
Iprolink - smpt.iprolink.co.nz
Juno - no relay
Lineone - smtp.lineone.net
LogonAmerica - mail.loa.com
Lycos - smtp.lycos.co.uk
Madasafish - smtp.madasafish.com
MegaNet - smtp.meganet.net
Mindspring - mail.mindspring.com
Mistral - smtp.mistral.co.uk
Mother.com - mail.mother.com
MSN - smtp.email.msn.com
Netcom - smtp.ix.netcom.com
Netlink - mail.netlink.co.nz
Netreach - smtp.netreach.net
Netzero - smtp.netzero.net
Nildram - smtp.nildram.co.uk
NNI.com - nni.com
NTLWorld - smtp.ntlworld.com
OneTel - mail.onetel.net.uk
OptimumOnline - mail.optonline.net
Orcon - mail.orcon.net.nz
PacBell - mail.pacbell.net
PAOnline.com - mail.paonline.com
Paradise - Net - smtp.paradise.net.nz
PeoplePC - mail.peoplepc.com
Pipeline - smtp.earthlink.net
Pipex - smtp.dial.pipex.com
Purplenet - smtp.purplenet.co.uk
Prodigy - smtp.prodigy.net
PSINet - bbr0-f1.sna.com
PSINet - relay.smtp.psi.net
Quadnet - mail.quadnet.net
RCN - smtp.rcn.com
River City Internet - mail.rcip.com
SBC - smtp.sbcglobal.net
Screaming.Net - smtp.tiscali.co.uk
Spire - mail.spire.com
Sprynet - smtp.earthlink.net
StarPower - smtp.starpower.net
Supanet - smtp.supanet.com
Telecom Xtra - smtp.xtra.co.nz
Telewest - smtp.blueyonder.co.uk
Tesconet - mail.tesco.net
Tiscali - smtp.tiscali.co.uk
Totalise - mail.totalise.co.uk
TTLC - mail.ttlc.net
UKGateway - smtp.ukgateway.net
UU.net - alterdial.uu.net
UU.net - mail.uu.net
V21 - smtp.v21.co.uk
Valinet - smtp.valinet.com
Verizon - outgoing.verizon.net
Virgin - smtp.virgin.net
Vispa - mail.vispa.com
Voicenet - mail.voicenet.com
Waitrose - smtpmail.waitrose.com
wcom.net - pop3host.wanmail.net
Webcom - smtp.webcom.com
Which Online - mail.which.net
Worldonline - smtp.tiscali.co.uk
Yahoo - smtp.mail.yahoo.com