V dne\u0161n\u00ed lekci se zam\u011b\u0159\u00edme na \u00fa\u010del a definici po\u0161tovn\u00edho serveru. Jedn\u00e1 se o velmi d\u016fle\u017eit\u00fd server a pravd\u011bpodobn\u011b jeden z prvn\u00edch, kter\u00fd je t\u0159eba vz\u00edt v \u00favahu p\u0159i n\u00e1vrhu nov\u00e9 infrastruktury.<\/p>\n
<\/p>\n
Ani\u017e byste o tom v\u016fbec p\u0159em\u00fd\u0161leli, pr\u00e1v\u011b v okam\u017eiku, kdy \u010dtete tyto \u0159\u00e1dky, p\u0159ij\u00edm\u00e1te a odes\u00edl\u00e1te e-maily. E-mail se od v\u00e1s dostane na jin\u00e9 m\u00edsto na sv\u011bt\u011b b\u011bhem n\u011bkolika sekund. Bereme to jako samoz\u0159ejmost a p\u0159\u00edli\u0161 se nezam\u00fd\u0161l\u00edme nad t\u00edm, jak k tomu vlastn\u011b doch\u00e1z\u00ed, ale jedn\u00e1 se o slo\u017eit\u00fd proces, kter\u00fd se uskute\u010d\u0148uje s pomoc\u00ed po\u0161tovn\u00edho serveru.<\/p>\n
Po\u0161tovn\u00ed server je po\u010d\u00edta\u010dov\u00e1 obdoba sousedsk\u00e9ho po\u0161\u0165\u00e1ka (jen o n\u011bco rychlej\u0161\u00ed), ale i kdy\u017e se zd\u00e1, \u017ee se e-mail ode\u0161le z jednoho po\u010d\u00edta\u010de do druh\u00e9ho v m\u017eiku, ve skute\u010dnosti proch\u00e1z\u00ed n\u011bkolika po\u0161tovn\u00edmi servery po cel\u00e9m sv\u011bt\u011b, ne\u017e doraz\u00ed na m\u00edsto ur\u010den\u00ed. Bez t\u011bchto server\u016f byste mohli pos\u00edlat e-maily pouze na stejn\u00e9 adresy v r\u00e1mci stejn\u00fdch dom\u00e9n.<\/p>\n
Existuj\u00ed dva typy kategori\u00ed po\u0161tovn\u00edch server\u016f \u2013 servery pro odchoz\u00ed po\u0161tu a servery pro p\u0159\u00edchoz\u00ed po\u0161tu.<\/p>\n
Pro odes\u00edl\u00e1n\u00ed po\u0161ty se pou\u017e\u00edv\u00e1 protokol zvan\u00fd SMTP (Simple Mail Transfer Protocol). Servery pro p\u0159\u00edjem po\u0161ty mohou vyu\u017e\u00edvat bu\u010f protokol POP3 (Post Office Protocol verze 3), nebo IMAP (Internet Message Access Protocol). Servery POP3 ukl\u00e1daj\u00ed e-maily na lok\u00e1ln\u00ed pevn\u00e9 disky nebo do po\u010d\u00edta\u010d\u016f, zat\u00edmco protokol IMAP ukl\u00e1d\u00e1 e-maily na servery, ale to jsou nudn\u00e9 v\u011bci.<\/p>\n
Zp\u011bt k na\u0161emu vysv\u011btlen\u00ed \u2013 V z\u00e1sad\u011b se stane toto: kdy\u017e v e-mailov\u00e9m klientovi stisknete tla\u010d\u00edtko \u2019Odeslat\u201c \u2013 a\u0165 u\u017e jde o Outlook, Gmail, Yahoo nebo jakoukoli jinou e-mailovou slu\u017ebu \u2013, e-mailov\u00fd klient se p\u0159ipoj\u00ed k SMTP serveru va\u0161\u00ed dom\u00e9ny. Pot\u00e9 e-mailov\u00fd klient komunikuje se serverem SMTP (nezapome\u0148te, \u017ee se jedn\u00e1 o odchoz\u00ed po\u0161tu) a p\u0159ed\u00e1v\u00e1 mu va\u0161i e-mailovou adresu, e-mailovou adresu p\u0159\u00edjemce a text zpr\u00e1vy spolu s p\u0159\u00edpadn\u00fdmi p\u0159\u00edlohami.<\/p>\n
SMTP server zpracov\u00e1v\u00e1 e-mailovou adresu p\u0159\u00edjemce. Pokud se jedn\u00e1 o lok\u00e1ln\u00ed dom\u00e9nu, nen\u00ed nutn\u00e9 \u017e\u00e1dn\u00e9 sm\u011brov\u00e1n\u00ed a zpr\u00e1va putuje p\u0159\u00edmo na POP nebo IMAP server dan\u00e9 dom\u00e9ny. Pokud se jedn\u00e1 o jinou dom\u00e9nu, bude muset SMTP server komunikovat se serverem t\u00e9to jin\u00e9 dom\u00e9ny.<\/p>\n
B\u011bhem sv\u00e9 dlouh\u00e9 cesty by se SMTP server m\u011bl setkat s DNS serverem (tj. serverem, kter\u00fd m\u00e1 na starosti p\u0159eklad e-mailov\u00fdch adres na IP adresy \u2013 o DNS serverech si pov\u00edme v n\u011bkter\u00e9m z budouc\u00edch \u010dl\u00e1nk\u016f). DNS server p\u0159evede e-mailovou adresu na IP adresu, co\u017e je jazyk, kter\u00fdm DNS server plynule hovo\u0159\u00ed.<\/p>\n
Nyn\u00ed, kdy\u017e m\u00e1 SMTP server spr\u00e1vnou IP adresu p\u0159\u00edjemce, m\u016f\u017ee se p\u0159ipojit k SMTP serveru p\u0159\u00edjemce. To se ned\u011bje p\u0159\u00edmo a zpr\u00e1va je obvykle sm\u011brov\u00e1na p\u0159es \u0159adu dal\u0161\u00edch SMTP server\u016f, dokud nedoraz\u00ed do c\u00edle. Pro tak k\u0159ehkou zpr\u00e1vu to rozhodn\u011b nen\u00ed snadn\u00e1 cesta, ale ve v\u011bt\u0161in\u011b p\u0159\u00edpad\u016f se tam dostane.<\/p>\n
A nakonec SMTP server p\u0159\u00edjemce zpr\u00e1vu p\u0159ijme, zkontroluje ji za \u00fa\u010delem ov\u011b\u0159en\u00ed dom\u00e9ny a u\u017eivatelsk\u00e9ho jm\u00e9na (tento krok je d\u016fle\u017eit\u00fd p\u0159i filtrov\u00e1n\u00ed spamu) a pokud je v\u0161e v po\u0159\u00e1dku, p\u0159ed\u00e1 ji k p\u0159e\u010dten\u00ed na POP server. Jakmile na e-mail kliknete, za\u010dne se stahovat. Protokol POP jej obvykle st\u00e1hne na m\u00edstn\u00ed pevn\u00fd disk, zat\u00edmco protokol IMAP pou\u017eije k sta\u017een\u00ed zpr\u00e1vy server.<\/p>\n
V tom v podstat\u011b spo\u010d\u00edv\u00e1 tajemstv\u00ed po\u0161tovn\u00edho serveru \u2013 jednoduch\u00fd, ale ve skute\u010dnosti velmi slo\u017eit\u00fd \u00fakol, kter\u00fd se odehr\u00e1v\u00e1 v pozad\u00ed.<\/p>\n
N\u011bkdo by se mohl zeptat: \u201cCo to m\u00e1 spole\u010dn\u00e9ho s m\u00fdm podnik\u00e1n\u00edm? Budu prost\u011b pou\u017e\u00edvat Gmail nebo Yahoo. Je to zdarma.\u201d Ano, je to zdarma, ale jsou i ti, kte\u0159\u00ed pot\u0159ebuj\u00ed hodn\u011b m\u00edsta \u2013 obvykle firmy \u2013 a ti \u010dasto mus\u00ed investovat do server\u016f.<\/p>\n
Krom\u011b po\u0159\u00edzen\u00ed server\u016f budete pot\u0159ebovat tak\u00e9 zp\u016fsob, jak p\u0159ij\u00edmat a odes\u00edlat e-maily, a nastavit si vlastn\u00ed e-mailovou konfiguraci a filtr.<\/p>\n
K tomuto \u00fa\u010delu mo\u017en\u00e1 pou\u017e\u00edv\u00e1te jeden ze dvou velmi popul\u00e1rn\u00edch program\u016f, jako je Postfix nebo Microsoft Exchange. Tyto programy cel\u00fd proces zjednodu\u0161uj\u00ed v pozad\u00ed.<\/p>\n
V kone\u010dn\u00e9m d\u016fsledku je po\u0161tovn\u00ed server serverem, kter\u00fd m\u00e1 na starosti odes\u00edl\u00e1n\u00ed a p\u0159ij\u00edm\u00e1n\u00ed e-mail\u016f v pozad\u00ed cel\u00e9ho procesu, mimo dosah koncov\u00e9ho u\u017eivatele. Jeho \u00fakolem je doru\u010dovat zpr\u00e1vy na spr\u00e1vnou adresu, p\u0159ij\u00edmat zpr\u00e1vy od spr\u00e1vn\u00fdch odes\u00edlatel\u016f, filtrovat nevhodn\u00fd obsah a v p\u0159\u00edpad\u011b pot\u0159eby ukl\u00e1dat archivovan\u00e9 e-maily. Proto\u017ee se to koncov\u00e9mu u\u017eivateli jev\u00ed jako snadn\u00e9, je to \u010dasto pova\u017eov\u00e1no za samoz\u0159ejmost, ale p\u0159esto je rozumn\u00e9 m\u00edt z\u00e1kladn\u00ed p\u0159edstavu o tom, jak po\u0161tovn\u00ed servery funguj\u00ed.<\/p>","protected":false},"excerpt":{"rendered":"
V dne\u0161n\u00ed lekci se zam\u011b\u0159\u00edme na \u00fa\u010del a definici po\u0161tovn\u00edho serveru. Jedn\u00e1 se o velmi d\u016fle\u017eit\u00fd server a pravd\u011bpodobn\u011b jeden z prvn\u00edch, kter\u00fd je t\u0159eba vz\u00edt v \u00favahu p\u0159i n\u00e1vrhu nov\u00e9 infrastruktury.<\/p>","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":["post-293","post","type-post","status-publish","format-standard","hentry","category-smtp-servers"],"_links":{"self":[{"href":"https:\/\/www.smtp-server.net\/cs\/wp-json\/wp\/v2\/posts\/293","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.smtp-server.net\/cs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.smtp-server.net\/cs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.smtp-server.net\/cs\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.smtp-server.net\/cs\/wp-json\/wp\/v2\/comments?post=293"}],"version-history":[{"count":1,"href":"https:\/\/www.smtp-server.net\/cs\/wp-json\/wp\/v2\/posts\/293\/revisions"}],"predecessor-version":[{"id":294,"href":"https:\/\/www.smtp-server.net\/cs\/wp-json\/wp\/v2\/posts\/293\/revisions\/294"}],"wp:attachment":[{"href":"https:\/\/www.smtp-server.net\/cs\/wp-json\/wp\/v2\/media?parent=293"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.smtp-server.net\/cs\/wp-json\/wp\/v2\/categories?post=293"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.smtp-server.net\/cs\/wp-json\/wp\/v2\/tags?post=293"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}