Как писать письма из Интернет в другие сети?

Сеть Адрес в сети Адрес в формате Internet
AppleLink user user@applelink.apple.com
BITNET user@site user@site.bitnet
BIX user user@dcibix.das.net
BMUG John Smith John.Smith@bmug.fidonet.org
CompuServe 7xxxx,yyy 7xxxx.yyy@compuserve.com
xxxxxx,yyyy xxxxxx.yyyy@compuserve.com
Connect NAME NAME@dcjcon.das.net
Econet user user@cdp.uucp
Envoy John (ID=userid) att!attmail!mhs!envoy!userid
FidoNet john smith at 1:2/3.4 john.smith@p4.f3.n2.z1.gate.phantom.msk.su
(john.smith@p4.f3.n2.z1.fidonet.org)
GEONET user at host user:host@map.das.net
GlassNet user user@glas.apc.org
EEE-CompmailI CMP1234 CMP1234%COMPMAIL@Intermail.ISI.ED
MCI John Smith (123-4567) 1234567@mcimail.com
MFENET user@mfenode user%mfenode.mfenet@nmfecc.arpa
NASAmail user user@nasamail.nasa.gov
Peacenet user user@cdp.uucp
user@cdp.igc.org
SINET node::user user@node.SINet.SLB.COM
node1::node::user user%node@node1.SINet.SLB.COM
SFMT user user@cdp.uucp
SPAN user@host user@host.span.NASA.gov
user%host.span@ames.arc.nasa.gov
THEnet user@host user%host.decnet@utadnx.cc.utexas.edu
USDAmail AGS1234 AGS1234%USDAMAIL@Intermail.ISI.EDU
SprintMail userid "John Smith"/organization/system/country /C=country/ADMD=system/O=organization/PN=John_Smith/DD.ID=userid/@Sprint.COM
HP brijitt HOSEK HP7100 A1 brijitt_HOSEK@HP7100_A1.desk.hp.com