{"id":7457,"date":"2026-10-12T13:03:54","date_gmt":"2026-10-12T11:03:54","guid":{"rendered":"https:\/\/eu.klytic.com\/spf-dkim-dmarc-ochrana-domeny\/"},"modified":"2026-10-12T16:14:01","modified_gmt":"2026-10-12T14:14:01","slug":"spf-dkim-dmarc-ochrana-domeny","status":"publish","type":"page","link":"https:\/\/eu.klytic.com\/cs\/spf-dkim-dmarc-ochrana-domeny\/","title":{"rendered":"SPF, DKIM a DMARC: co chr\u00e1n\u00ed a co nechr\u00e1n\u00ed"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-page\" data-elementor-id=\"7457\" class=\"elementor elementor-7457 elementor-6295\" data-elementor-post-type=\"page\">\n\t\t\t\t<div class=\"elementor-element elementor-element-36c2839 e-con-full kly-g e-flex e-con e-parent\" data-id=\"36c2839\" data-element_type=\"container\" data-e-type=\"container\" data-settings=\"{&quot;ekit_has_onepagescroll_dot&quot;:&quot;yes&quot;}\">\n\t\t<div class=\"elementor-element elementor-element-e2eec95 e-con-full kly-g-hero e-flex e-con e-parent\" data-id=\"e2eec95\" data-element_type=\"container\" data-e-type=\"container\" data-settings=\"{&quot;ekit_has_onepagescroll_dot&quot;:&quot;yes&quot;}\">\n\t\t<div class=\"elementor-element elementor-element-40aa151 e-con-full kly-g-hero-in e-flex e-con e-parent\" data-id=\"40aa151\" data-element_type=\"container\" data-e-type=\"container\" data-settings=\"{&quot;ekit_has_onepagescroll_dot&quot;:&quot;yes&quot;}\">\n\t\t\t\t<div class=\"elementor-element elementor-element-44ffdcc elementor-widget elementor-widget-text-editor\" data-id=\"44ffdcc\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;ekit_we_effect_on&quot;:&quot;none&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<p class=\"kly-g-crumb\"><a href=\"\/\">Dom\u016f<\/a><span>\u203a<\/span>P\u0159\u00edru\u010dky<span>\u203a<\/span>Zabezpe\u010den\u00ed e-mail\u016f<\/p><p class=\"kly-g-pill\" style=\"--pill:#f87171\">Zabezpe\u010den\u00ed e-mail\u016f \u00b7 Pochopit<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-c12c655 elementor-widget elementor-widget-heading\" data-id=\"c12c655\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;ekit_we_effect_on&quot;:&quot;none&quot;}\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h1 class=\"elementor-heading-title elementor-size-default\">SPF, DKIM a DMARC: co chr\u00e1n\u00ed a co nechr\u00e1n\u00ed<\/h1>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-af97082 elementor-widget elementor-widget-text-editor\" data-id=\"af97082\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;ekit_we_effect_on&quot;:&quot;none&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<p class=\"kly-g-lead\">SPF \u0159\u00edk\u00e1, kter\u00e9 servery sm\u011bj\u00ed odes\u00edlat za dom\u00e9nu, DKIM zpr\u00e1vu podepisuje, DMARC ov\u011b\u0159uje, \u017ee jeden z nich odpov\u00edd\u00e1 dom\u00e9n\u011b zobrazen\u00e9 v poli \u201eOd\u201c, a \u0159\u00edk\u00e1, co d\u011blat p\u0159i ne\u00fasp\u011bchu. Spole\u010dn\u011b br\u00e1n\u00ed nezn\u00e1m\u00e9mu, aby pou\u017e\u00edval p\u0159esn\u011b va\u0161i dom\u00e9nu. Text ne\u010dtou: podobn\u00e1 dom\u00e9na, klamav\u00e9 zobrazovan\u00e9 jm\u00e9no nebo kompromitovan\u00fd \u00fa\u010det projdou.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-d7288a0 elementor-widget elementor-widget-text-editor\" data-id=\"d7288a0\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;ekit_we_effect_on&quot;:&quot;none&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<p class=\"kly-g-meta\"><span>Aktualizov\u00e1no: <b>\u0159\u00edjen 2026<\/b><\/span><span><b>6 min<\/b><\/span><span>Citovan\u00e9 ofici\u00e1ln\u00ed zdroje<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-dd4715a e-con-full kly-g-body e-flex e-con e-parent\" data-id=\"dd4715a\" data-element_type=\"container\" data-e-type=\"container\" data-settings=\"{&quot;ekit_has_onepagescroll_dot&quot;:&quot;yes&quot;}\">\n\t\t<div class=\"elementor-element elementor-element-d949fc8 e-con-full kly-g-article e-flex e-con e-parent\" data-id=\"d949fc8\" data-element_type=\"container\" data-e-type=\"container\" data-settings=\"{&quot;ekit_has_onepagescroll_dot&quot;:&quot;yes&quot;}\">\n\t\t\t\t<div class=\"elementor-element elementor-element-0f3c2db elementor-widget elementor-widget-text-editor\" data-id=\"0f3c2db\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;ekit_we_effect_on&quot;:&quot;none&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<h2>SPF: kdo sm\u00ed odes\u00edlat<\/h2><p>RFC 7208 vych\u00e1z\u00ed ze zji\u0161t\u011bn\u00ed: nic v e-mailov\u00e9m protokolu nebr\u00e1n\u00ed serveru uv\u00e9st jakoukoli adresu odes\u00edlatele. SPF umo\u017e\u0148uje vlastn\u00edkovi dom\u00e9ny zve\u0159ejnit v DNS seznam server\u016f opr\u00e1vn\u011bn\u00fdch odes\u00edlat jej\u00edm jm\u00e9nem a p\u0159ij\u00edmaj\u00edc\u00edmu serveru toto opr\u00e1vn\u011bn\u00ed ov\u011b\u0159it.<\/p><p>Dv\u011b up\u0159esn\u011bn\u00ed m\u011bn\u00ed v\u0161e:<\/p><ul><li>SPF ov\u011b\u0159uje ob\u00e1lkovou adresu (adresu z komunikace mezi servery, takzvanou \u201eMAIL FROM\u201c) a jm\u00e9no ohl\u00e1\u0161en\u00e9 serverem, ne adresu, kterou p\u0159\u00edjemce \u010dte v poli \u201eOd\u201c.<\/li><li>SPF posuzuje posledn\u00ed server, kter\u00fd zpr\u00e1vu doru\u010dil. Kdy\u017e je zpr\u00e1va p\u0159eposl\u00e1na jin\u00fdm serverem, u\u017e ji nedoru\u010duje server opr\u00e1vn\u011bn\u00fd p\u016fvodn\u00ed dom\u00e9nou: ov\u011b\u0159en\u00ed m\u016f\u017ee selhat, p\u0159esto\u017ee je zpr\u00e1va legitimn\u00ed.<\/li><\/ul><p>Dom\u00e9na zve\u0159ej\u0148uje jen jeden z\u00e1znam SPF. Mus\u00ed v n\u011bm b\u00fdt v\u0161echny zdroje odes\u00edl\u00e1n\u00ed: e-mailov\u00fd syst\u00e9m, faktura\u010dn\u00ed software, n\u00e1stroj pro newslettery, CRM, kop\u00edrka, kter\u00e1 skenuje do e-mailu.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-2624513 elementor-widget elementor-widget-text-editor\" data-id=\"2624513\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;ekit_we_effect_on&quot;:&quot;none&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<h2>DKIM: zpr\u00e1va je podepsan\u00e1<\/h2><p>Podle RFC 6376 umo\u017e\u0148uje DKIM vlastn\u00edkovi podepisuj\u00edc\u00ed dom\u00e9ny p\u0159ihl\u00e1sit se k \u010d\u00e1ste\u010dn\u00e9 odpov\u011bdnosti za zpr\u00e1vu pomoc\u00ed kryptografick\u00e9ho podpisu. Ve\u0159ejn\u00fd kl\u00ed\u010d je v DNS. Ov\u011b\u0159en\u00ed podpisu prokazuje, \u017ee se podepsan\u00e9 \u010d\u00e1sti od podpisu nezm\u011bnily.<\/p><p>Podpis cestuje se zpr\u00e1vou. P\u0159e\u010dk\u00e1 proto p\u0159ed\u00e1n\u00ed p\u0159es relay nebo p\u0159eposl\u00e1n\u00ed l\u00e9pe ne\u017e SPF, pokud tento mezil\u00e9hl\u00fd server nem\u011bn\u00ed p\u0159edm\u011bt ani t\u011blo zpr\u00e1vy. Distribu\u010dn\u00ed seznam, kter\u00fd na konec zpr\u00e1vy p\u0159id\u00e1 pozn\u00e1mku, jej poru\u0161\u00ed.<\/p><p>Co DKIM podle tot\u00e9\u017e RFC ned\u011bl\u00e1: zpr\u00e1vu ne\u0161ifruje, ne\u00fasp\u011bch nevy\u017eaduje jej\u00ed odm\u00edtnut\u00ed a podepisuj\u00edc\u00ed dom\u00e9na nemus\u00ed b\u00fdt ta, kter\u00e1 je zobrazena v poli \u201eOd\u201c. Pr\u00e1v\u011b tuto mezeru zapl\u0148uje DMARC.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-287c507 elementor-widget elementor-widget-text-editor\" data-id=\"287c507\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;ekit_we_effect_on&quot;:&quot;none&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<h2>DMARC: zarovn\u00e1n\u00ed a politika<\/h2><p>RFC 7489 definuje DMARC jako prost\u0159edek, j\u00edm\u017e vlastn\u00edk dom\u00e9ny vyjad\u0159uje politiku na \u00farovni dom\u00e9ny. Mechanismus stoj\u00ed na zarovn\u00e1n\u00ed (alignment): dom\u00e9na adresy zobrazen\u00e9 v poli \u201eOd\u201c mus\u00ed odpov\u00eddat dom\u00e9n\u011b ov\u011b\u0159en\u00e9 pomoc\u00ed SPF nebo DKIM. Pokud nen\u00ed zarovnan\u00fd ani jeden, DMARC sel\u017ee.<\/p><p>Dom\u00e9na pak zve\u0159ejn\u00ed, co si p\u0159eje:<\/p><ul><li><strong>none<\/strong>: nevy\u017eaduje se \u017e\u00e1dn\u00e1 akce, pouze se sleduje;<\/li><li><strong>quarantine<\/strong>: se zpr\u00e1vou zach\u00e1zet jako s podez\u0159elou;<\/li><li><strong>reject<\/strong>: zpr\u00e1vu odm\u00edtnout.<\/li><\/ul><p>DMARC po\u010d\u00edt\u00e1 tak\u00e9 s reporty: agregovan\u00fdmi reporty, kter\u00e9 shrnuj\u00ed, kter\u00e9 servery odes\u00edlaly jm\u00e9nem dom\u00e9ny a s jak\u00fdm v\u00fdsledkem, a reporty o selh\u00e1n\u00ed, zpr\u00e1vu po zpr\u00e1v\u011b. Pr\u00e1v\u011b d\u00edky nim lze odhalit zapomenut\u00fd n\u00e1stroj, kter\u00fd za v\u00e1s odes\u00edl\u00e1, nebo n\u011bkoho, kdo zneu\u017e\u00edv\u00e1 va\u0161i dom\u00e9nu.<\/p><div class=\"kly-table\"><table><thead><tr><th>Mechanismus<\/th><th>Co ov\u011b\u0159uje<\/th><th>Na co se ned\u00edv\u00e1<\/th><\/tr><\/thead><tbody><tr><td>SPF<\/td><td>Server, kter\u00fd zpr\u00e1vu doru\u010duje, je opr\u00e1vn\u011bn\u00fd pro ob\u00e1lkovou dom\u00e9nu<\/td><td>Zobrazen\u00e1 adresa, obsah<\/td><\/tr><tr><td>DKIM<\/td><td>Podepsan\u00e1 zpr\u00e1va nebyla pozm\u011bn\u011bna; dom\u00e9na za ni p\u0159eb\u00edr\u00e1 odpov\u011bdnost<\/td><td>Zobrazen\u00e1 adresa, poctivost obsahu<\/td><\/tr><tr><td>DMARC<\/td><td>Zobrazen\u00e1 dom\u00e9na je zarovnan\u00e1 se SPF nebo DKIM; politika p\u0159i ne\u00fasp\u011bchu<\/td><td>Podobn\u00e9 dom\u00e9ny, zobrazovan\u00e9 jm\u00e9no, text<\/td><\/tr><\/tbody><\/table><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-9524d83 elementor-widget elementor-widget-text-editor\" data-id=\"9524d83\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;ekit_we_effect_on&quot;:&quot;none&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<h2>Blokuje DMARC phishing?<\/h2><p>Blokuje \u010d\u00e1st zneu\u017e\u00edv\u00e1n\u00ed dom\u00e9ny, ne phishing obecn\u011b. RFC 7489 to \u0159\u00edk\u00e1 v\u00fdslovn\u011b: DMARC se nezab\u00fdv\u00e1 vizu\u00e1ln\u011b podobn\u00fdmi dom\u00e9nov\u00fdmi jm\u00e9ny ani zneu\u017eit\u00edm zobrazovan\u00e9ho jm\u00e9na a anal\u00fdza obsahu je mimo jeho rozsah. Nesna\u017e\u00ed se \u0159e\u0161it v\u0161echny probl\u00e9my podvodn\u00e9 po\u0161ty.<\/p><p>Konkr\u00e9tn\u011b DMARC nevid\u00ed:<\/p><ul><li><strong>podobnou dom\u00e9nu<\/strong>: podvodn\u00edk dokonale ov\u011b\u0159\u00ed svou vlastn\u00ed dom\u00e9nu, kter\u00e1 se podob\u00e1 t\u00e9 va\u0161\u00ed;<\/li><li><strong>zneu\u017eit\u00e9 zobrazovan\u00e9 jm\u00e9no<\/strong>: \u201eOdd\u011blen\u00ed \u00fa\u010dt\u00e1rny\u201c p\u00ed\u0161e z adresy, kter\u00e1 s n\u00edm nem\u00e1 nic spole\u010dn\u00e9ho;<\/li><li><strong>kompromitovan\u00fd \u00fa\u010det<\/strong>, kter\u00fd podepisuje spr\u00e1vn\u011b, proto\u017ee odes\u00edl\u00e1 skute\u010dn\u00fd server;<\/li><li><strong>zpr\u00e1vu, kter\u00e1 s va\u0161\u00ed dom\u00e9nou nesouvis\u00ed<\/strong>: fale\u0161n\u00e9 upozorn\u011bn\u00ed od p\u0159epravce p\u0159ich\u00e1z\u00ed z dom\u00e9ny, kter\u00e1 nem\u00e1 s tou va\u0161\u00ed nic spole\u010dn\u00e9ho;<\/li><li><strong>dom\u00e9nu bez politiky<\/strong>: pokud napodoben\u00e1 dom\u00e9na zve\u0159ej\u0148uje \u201enone\u201c, p\u0159\u00edjemce nem\u00e1 pokyn k odm\u00edtnut\u00ed.<\/li><\/ul><p>Tyto p\u0159\u00edpady pat\u0159\u00ed k jin\u00fdm anal\u00fdz\u00e1m: podobnost dom\u00e9n, reputace, obsah, chov\u00e1n\u00ed. Viz <a href='\/cs\/spam-phishing-malware-kompromitovany-ucet\/'>spam, phishing, malware a kompromitovan\u00fd \u00fa\u010det<\/a>.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-354e9b5 elementor-widget elementor-widget-text-editor\" data-id=\"354e9b5\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;ekit_we_effect_on&quot;:&quot;none&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<h2>P\u0159eposl\u00e1n\u00ed a distribu\u010dn\u00ed seznamy: ARC<\/h2><p>P\u0159eposl\u00e1n\u00ed \u010dasto poru\u0161\u00ed SPF, seznam, kter\u00fd zpr\u00e1vu uprav\u00ed, poru\u0161\u00ed DKIM, a DMARC pak u legitimn\u00ed zpr\u00e1vy sel\u017ee. ARC, popsan\u00fd v RFC 8617 (experiment\u00e1ln\u00ed status), umo\u017e\u0148uje ka\u017ed\u00e9mu prost\u0159edn\u00edkovi osv\u011bd\u010dit v\u00fdsledek ov\u011b\u0159en\u00ed, kter\u00fd zjistil. Kone\u010dn\u00fd server se m\u016f\u017ee rozhodnout jej zohlednit.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-2f8a2a6 elementor-widget elementor-widget-text-editor\" data-id=\"2f8a2a6\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;ekit_we_effect_on&quot;:&quot;none&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<h2>Chr\u00e1nit svou dom\u00e9nu, filtrovat, co p\u0159ich\u00e1z\u00ed<\/h2><p>Jsou to dv\u011b t\u00e9mata, kter\u00e1 se \u010dasto zam\u011b\u0148uj\u00ed.<\/p><ul><li><strong>Chr\u00e1nit odes\u00edlaj\u00edc\u00ed dom\u00e9nu<\/strong>: zve\u0159ejnit SPF, DKIM a DMARC pro va\u0161i dom\u00e9nu, aby ostatn\u00ed mohli odm\u00edtat zpr\u00e1vy, kter\u00e9 ji zneu\u017e\u00edvaj\u00ed. Zve\u0159ej\u0148ujete vy; uplat\u0148uj\u00ed p\u0159\u00edjemci.<\/li><li><strong>Filtrovat, co p\u0159ich\u00e1z\u00ed<\/strong>: ov\u011b\u0159ovat z\u00e1znamy ostatn\u00edch dom\u00e9n u po\u0161ty, kterou p\u0159ij\u00edm\u00e1te, a pak uplatnit v\u0161echny ostatn\u00ed anal\u00fdzy.<\/li><\/ul><h3>Postupn\u00e9 zaveden\u00ed<\/h3><ol><li>Soupis v\u0161eho, co odes\u00edl\u00e1 jm\u00e9nem dom\u00e9ny.<\/li><li>Jedin\u00fd z\u00e1znam SPF, kter\u00fd je povoluje; podpis DKIM pro ka\u017edou slu\u017ebu, kter\u00e1 um\u00ed podepisovat.<\/li><li>DMARC v re\u017eimu \u201enone\u201c s adresou pro p\u0159\u00edjem report\u016f.<\/li><li>\u010cten\u00ed report\u016f po n\u011bkolik t\u00fddn\u016f; oprava zapomenut\u00fdch zdroj\u016f.<\/li><li>P\u0159echod na \u201equarantine\u201c a pot\u00e9 na \u201ereject\u201c, jakmile jsou v\u0161echny legitimn\u00ed odes\u00edlan\u00e9 zpr\u00e1vy zarovnan\u00e9.<\/li><\/ol><p>P\u0159\u00edklad pro ilustraci. Kancel\u00e1\u0159 zve\u0159ejn\u00ed DMARC v re\u017eimu \u201enone\u201c a \u010dte sv\u00e9 prvn\u00ed reporty. Zjist\u00ed v nich t\u0159i zdroje: sv\u016fj e-mailov\u00fd syst\u00e9m, spr\u00e1vn\u011b zarovnan\u00fd; sv\u016fj faktura\u010dn\u00ed software, kter\u00fd odes\u00edl\u00e1 faktury s dom\u00e9nou kancel\u00e1\u0159e bez podpisu DKIM; a nezn\u00e1m\u00fd server v zahrani\u010d\u00ed, kter\u00fd jej\u00edm jm\u00e9nem pos\u00edl\u00e1 stovky zpr\u00e1v. Oprav\u00ed faktura\u010dn\u00ed software, po\u010dk\u00e1 na \u010dist\u00fd cyklus report\u016f a pak p\u0159ejde na \u201equarantine\u201c: p\u0159\u00edjemci, kte\u0159\u00ed DMARC uplat\u0148uj\u00ed, nyn\u00ed zach\u00e1zej\u00ed se zpr\u00e1vami nezn\u00e1m\u00e9ho serveru jako s podez\u0159el\u00fdmi.<\/p><p>Kdy\u017e se m\u011bn\u00ed e-mailov\u00fd syst\u00e9m, p\u0159ipravuj\u00ed se tyto z\u00e1znamy p\u0159ed zm\u011bnou MX. Pr\u016fvodce <a href='\/cs\/migrace-e-mailu-bez-preruseni\/'>migrace e-mailu bez p\u0159eru\u0161en\u00ed provozu<\/a> tento okam\u017eik popisuje; zde jej neopakujeme.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-152196c elementor-widget elementor-widget-text-editor\" data-id=\"152196c\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;ekit_we_effect_on&quot;:&quot;none&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<h2>\u010cast\u00e9 dotazy<\/h2><h3>Chr\u00e1n\u00ed politika DMARC \u201enone\u201c?<\/h3><p>Ne. Umo\u017e\u0148uje sledovat d\u00edky report\u016fm. Ochrana za\u010d\u00edn\u00e1 s \u201equarantine\u201c nebo \u201ereject\u201c.<\/p><h3>Pro\u010d legitimn\u00ed zpr\u00e1va neprojde DMARC?<\/h3><p>Nej\u010dast\u011bji kv\u016fli p\u0159eposl\u00e1n\u00ed, distribu\u010dn\u00edmu seznamu nebo slu\u017eb\u011b, kter\u00e1 za v\u00e1s odes\u00edl\u00e1, ani\u017e by byla uvedena v SPF nebo podepisovala DKIM.<\/p><h3>N\u00e1\u0161 e-mailov\u00fd syst\u00e9m nepodepisuje DKIM: co d\u011blat?<\/h3><p>Br\u00e1na um\u00edst\u011bn\u00e1 na cest\u011b odes\u00edlan\u00e9 po\u0161ty m\u016f\u017ee podepisovat za n\u011bj. Viz <a href='\/cs\/ochrana-stavajiciho-e-mailu\/'>Ochrana e-mailov\u00e9ho syst\u00e9mu, kter\u00fd u\u017e m\u00e1te<\/a>.<\/p><h3>Kde si p\u0159e\u010d\u00edst v\u00fdsledek t\u011bchto kontrol u p\u0159ijat\u00e9 zpr\u00e1vy?<\/h3><p>V hlavi\u010dk\u00e1ch zpr\u00e1vy. Pro Klytic MTA viz <a href='\/cs\/audit-rozhodnuti-filtru\/'>Jak \u010d\u00edst a exportovat rozhodnut\u00ed filtru<\/a>.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-c1b8b85 kly-g-klytic elementor-widget elementor-widget-text-editor\" data-id=\"c1b8b85\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;ekit_we_effect_on&quot;:&quot;none&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<h2>Kde se nach\u00e1z\u00ed Klytic<\/h2><p><a href='\/cs\/klytic-mta\/'>Klytic MTA<\/a> \u0159e\u0161\u00ed ob\u011b t\u00e9mata, p\u0159ed jak\u00fdmkoli e-mailov\u00fdm syst\u00e9mem:<\/p><ul><li><strong>Essential a Advanced<\/strong>: kontrola DKIM, SPF a MX; ov\u011b\u0159en\u00ed DMARC, i u p\u0159eposlan\u00fdch zpr\u00e1v d\u00edky ARC; podpis DKIM odes\u00edlan\u00fdch zpr\u00e1v, i kdy\u017e to v\u00e1\u0161 e-mailov\u00fd syst\u00e9m ned\u011bl\u00e1.<\/li><li><strong>Advanced<\/strong>: konzole DMARC s reporty va\u0161ich dom\u00e9n, upozorn\u011bn\u00edmi a doporu\u010den\u00edmi k n\u00e1prav\u011b, pro postupn\u00fd p\u0159echod na \u201ereject\u201c.<\/li><\/ul><p>DMARC je jen jedna vrstva: Klytic MTA p\u0159id\u00e1v\u00e1 detekci podobn\u00fdch dom\u00e9n, zobrazovan\u00e9ho jm\u00e9na a podvodn\u00fdch sc\u00e9n\u00e1\u0159\u016f, popsanou v pr\u016fvodci <a href='\/cs\/podvod-ceo-fraud-zneuziti-identity\/'>zneu\u017eit\u00ed identity a podvod typu CEO fraud<\/a>.<\/p><p>Pokud pou\u017e\u00edv\u00e1te <a href='\/cs\/klytic-mail\/'>Klytic Mail<\/a>, jsou SPF, DKIM a DMARC nastaveny pro va\u0161i dom\u00e9nu: to je ochrana odes\u00edlaj\u00edc\u00ed dom\u00e9ny. Klytic MTA lze sjednat s Klytic Mail i bez n\u011bj.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-d1c1ff2 kly-g-sources elementor-widget elementor-widget-text-editor\" data-id=\"d1c1ff2\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;ekit_we_effect_on&quot;:&quot;none&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<h2>Zdroje<\/h2><p>Ov\u011b\u0159eno v \u0159\u00edjnu 2026.<\/p><ul><li>RFC 7208, SPF: vlastn\u00edk dom\u00e9ny zve\u0159ej\u0148uje hostitele opr\u00e1vn\u011bn\u00e9 pou\u017e\u00edvat jeho dom\u00e9nu v identit\u011b \u201eMAIL FROM\u201c nebo \u201eHELO\u201c a p\u0159\u00edjemce toto opr\u00e1vn\u011bn\u00ed ov\u011b\u0159uje. <a href='https:\/\/www.rfc-editor.org\/rfc\/rfc7208' rel='noopener' target='_blank'>rfc-editor.org<\/a><\/li><li>RFC 6376, DKIM: dom\u00e9na se kryptografick\u00fdm podpisem hl\u00e1s\u00ed k odpov\u011bdnosti za zpr\u00e1vu; \u017e\u00e1dn\u00e9 \u0161ifrov\u00e1n\u00ed, \u017e\u00e1dn\u00e9 povinn\u00e9 odm\u00edtnut\u00ed, podepisuj\u00edc\u00ed dom\u00e9na se m\u016f\u017ee li\u0161it od zobrazen\u00e9ho autora. <a href='https:\/\/www.rfc-editor.org\/rfc\/rfc6376' rel='noopener' target='_blank'>rfc-editor.org<\/a><\/li><li>RFC 7489, DMARC: zarovn\u00e1n\u00ed dom\u00e9ny z pole \u201eFrom\u201c se SPF nebo DKIM, politiky none, quarantine a reject, agregovan\u00e9 reporty a reporty o selh\u00e1n\u00ed; vizu\u00e1ln\u011b podobn\u00e9 dom\u00e9ny, zobrazovan\u00e9 jm\u00e9no a anal\u00fdza obsahu mimo rozsah. <a href='https:\/\/www.rfc-editor.org\/rfc\/rfc7489' rel='noopener' target='_blank'>rfc-editor.org<\/a><\/li><li>RFC 9989 (kv\u011bten 2026), kter\u00e9 nahrazuje RFC 7489: stejn\u00e9 hodnoty politiky a stejn\u00e9 v\u00fdjimky (podobn\u00e9 dom\u00e9ny, zobrazovan\u00e9 jm\u00e9no). <a href='https:\/\/www.rfc-editor.org\/rfc\/rfc9989' rel='noopener' target='_blank'>rfc-editor.org<\/a><\/li><li>RFC 8617, ARC (experiment\u00e1ln\u00ed): ov\u011b\u0159en\u00fd \u0159et\u011bzec p\u0159enosu; p\u0159\u00edjemce DMARC m\u016f\u017ee p\u0159ijmout hodnocen\u00ed nesen\u00e1 platn\u00fdm \u0159et\u011bzcem ARC. <a href='https:\/\/www.rfc-editor.org\/rfc\/rfc8617' rel='noopener' target='_blank'>rfc-editor.org<\/a><\/li><li>Klytic, str\u00e1nka Klytic MTA: kontroly ov\u011b\u0159en\u00ed, odchoz\u00ed podpis DKIM a konzole DMARC v nab\u00eddk\u00e1ch Essential a Advanced, dopl\u0148ky, zp\u016fsoby nasazen\u00ed, uveden\u00ed do provozu zm\u011bnou MX. <a href='https:\/\/www.klytic.com\/klytic-mta\/' rel='noopener' target='_blank'>klytic.com<\/a><\/li><\/ul>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-f7cd1ef e-con-full kly-g-aside e-flex e-con e-parent\" data-id=\"f7cd1ef\" data-element_type=\"container\" data-e-type=\"container\" data-settings=\"{&quot;ekit_has_onepagescroll_dot&quot;:&quot;yes&quot;}\">\n\t\t\t\t<div class=\"elementor-element elementor-element-5e97545 elementor-widget elementor-widget-html\" data-id=\"5e97545\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;ekit_we_effect_on&quot;:&quot;none&quot;}\" data-widget_type=\"html.default\">\n\t\t\t\t\t<nav class=\"kly-g-toc\" aria-label=\"Na t\u00e9to str\u00e1nce\"><p>Na t\u00e9to str\u00e1nce<\/p><ol><\/ol><\/nav>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-fd8dc8b elementor-widget elementor-widget-text-editor\" data-id=\"fd8dc8b\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;ekit_we_effect_on&quot;:&quot;none&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<div class=\"kly-g-cta\"><h3>Ov\u011b\u0159ovat a podepisovat p\u0159ed va\u0161\u00edm e-mailov\u00fdm syst\u00e9mem<\/h3><p>Klytic MTA ov\u011b\u0159uje SPF, DKIM a DMARC p\u0159i p\u0159\u00edjmu a podepisuje va\u0161e odes\u00edlan\u00e9 zpr\u00e1vy.<\/p><p><a class=\"kly-g-btn\" href=\"\/cs\/kontakt\/\">Promluvit s poradcem \u2192<\/a><\/p><p style=\"margin:0\"><a class=\"kly-g-btn ghost\" href=\"\/cs\/klytic-mta\/\">Objevte Klytic MTA<\/a><\/p><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-e3a0061 e-con-full kly-g-related e-flex e-con e-parent\" data-id=\"e3a0061\" data-element_type=\"container\" data-e-type=\"container\" data-settings=\"{&quot;ekit_has_onepagescroll_dot&quot;:&quot;yes&quot;}\">\n\t\t\t\t<div class=\"elementor-element elementor-element-05506da elementor-widget elementor-widget-text-editor\" data-id=\"05506da\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;ekit_we_effect_on&quot;:&quot;none&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<h2>P\u0159e\u010dt\u011bte si tak\u00e9<\/h2><div class=\"kly-g-grid\"><a class=\"kly-g-card\" href=\"\/cs\/migrace-e-mailu-bez-preruseni\/\" style=\"--cat:#0077cc\"><span class=\"c\">P\u0159\u00edru\u010dky<\/span><span class=\"t\">Jak migrovat firemn\u00ed e-mail bez p\u0159eru\u0161en\u00ed provozu?<\/span><span class=\"q\">Soub\u011bh platforem, druh\u00fd pr\u016fchod, TTL z\u00e1znamu MX, SPF, DKIM, DMARC a zku\u0161ebn\u00ed odesl\u00e1n\u00ed: jak zm\u011bnit e-mailovou slu\u017ebu bez ztr\u00e1ty po\u0161ty a co z\u016fstane viditeln\u00e9.<\/span><span class=\"m\"><span>P\u0159\u00edru\u010dky<\/span><b>\u010c\u00edst \u2192<\/b><\/span><\/a><a class=\"kly-g-card\" href=\"\/cs\/spam-phishing-malware-kompromitovany-ucet\/\" style=\"--cat:#dc2626\"><span class=\"c\">Pochopit \u00b7 Zabezpe\u010den\u00ed e-mail\u016f<\/span><span class=\"t\">Spam, phishing, malware a kompromitovan\u00fd \u00fa\u010det<\/span><span class=\"q\">\u010cty\u0159i hrozby p\u0159ich\u00e1zej\u00ed stejn\u00fdmi dve\u0159mi a ne\u0159e\u0161\u00ed se stejn\u011b. Co ka\u017edou z nich prozrad\u00ed, co ji zastav\u00ed a pro\u010d samotn\u00fd antispam u\u017e nesta\u010d\u00ed.<\/span><span class=\"m\"><span>6 min \u010dten\u00ed<\/span><b>\u010c\u00edst \u2192<\/b><\/span><\/a><a class=\"kly-g-card\" href=\"\/cs\/ochrana-stavajiciho-e-mailu\/\" style=\"--cat:#dc2626\"><span class=\"c\">Pochopit \u00b7 Zabezpe\u010den\u00ed e-mail\u016f<\/span><span class=\"t\">Ochrana e-mailov\u00e9ho syst\u00e9mu, kter\u00fd u\u017e m\u00e1te<\/span><span class=\"q\">Microsoft 365, Google Workspace, Exchange: bezpe\u010dnostn\u00ed br\u00e1nu lze p\u0159idat beze zm\u011bny e-mailov\u00e9ho syst\u00e9mu. Co se m\u011bn\u00ed, kdo to nastavuje a omezen\u00ed.<\/span><span class=\"m\"><span>7 min \u010dten\u00ed<\/span><b>\u010c\u00edst \u2192<\/b><\/span><\/a><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-539316dd e-con e-atomic-element e-div-block-base e-default-div e-c9fd865-4a50 \" data-id=\"539316dd\" data-element_type=\"e-div-block\" data-e-type=\"e-div-block\" data-interaction-id=\"539316dd\" data-e-type=\"e-div-block\" data-id=\"539316dd\">\n    <div class=\"elementor-element elementor-element-4f79afcb e-con e-atomic-element e-div-block-base e-default-div e-4fa9fe-ce86 \" data-id=\"4f79afcb\" data-element_type=\"e-div-block\" data-e-type=\"e-div-block\" data-interaction-id=\"4f79afcb\" data-e-type=\"e-div-block\" data-id=\"4f79afcb\">\n    \t\t\t<p class=\"e-4dcf5c70-2ec7 e-paragraph-base e-default-p\" data-interaction-id=\"330a7a35\" data-e-type=\"widget\" data-id=\"330a7a35\">Uv\u00edtac\u00ed nab\u00eddka<\/p>\n\t\t\t\t\t<h2 data-interaction-id=\"56f1f7d5\" class=\"e-347faa43-4e20 e-heading-base e-default-h2\" data-e-type=\"widget\" data-id=\"56f1f7d5\">30 dn\u00ed zku\u0161ebn\u00ed verze zdarma a migrace s asistenc\u00ed<\/h2>\n\t\t\t\t\t<p class=\"e-7f6310da-1caa e-paragraph-base e-default-p\" data-interaction-id=\"2ce27288\" data-e-type=\"widget\" data-id=\"2ce27288\">Zku\u0161ebn\u00ed nab\u00eddka bez z\u00e1vazk\u016f. N\u00e1\u0161 poradce v\u00e1m zavol\u00e1, aby poznal va\u0161e pot\u0159eby a p\u0159ipravil va\u0161e prost\u0159ed\u00ed Klytic.<\/p>\n\t\t<div class=\"elementor-element elementor-element-35ea29a1 e-con e-atomic-element e-div-block-base e-default-div e-1cd48b22-e6da \" data-id=\"35ea29a1\" data-element_type=\"e-div-block\" data-e-type=\"e-div-block\" data-interaction-id=\"35ea29a1\" data-e-type=\"e-div-block\" data-id=\"35ea29a1\">\n    \t\t\t<a href=\"\/essai-gratuit\/\" target=\"_self\" class=\"e-4a7886e3-652d e-button-base e-default-a\" data-interaction-id=\"19bfa8f1\" data-e-type=\"widget\" data-id=\"19bfa8f1\">\n\t\ud83d\ude80 Zah\u00e1jit zku\u0161ebn\u00ed verzi zdarma\n<\/a>\n\t\t\t\t\t<a href=\"\/tarifs\/\" target=\"_self\" class=\"e-137e863d-dd0d e-button-base e-default-a\" data-interaction-id=\"326d82ab\" data-e-type=\"widget\" data-id=\"326d82ab\">\n\tZobrazit cen\u00edk\n<\/a>\n\t\t\n<\/div>\n\n<\/div>\n\n<\/div>\n\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"elementor_header_footer","meta":{"_seopress_titles_title":"SPF, DKIM a DMARC: co chr\u00e1n\u00ed a co ne | Klytic","_seopress_titles_desc":"SPF, DKIM a DMARC vysv\u011btlen\u011b: co kter\u00fd ov\u011b\u0159uje, pro\u010d DMARC neblokuje phishing obecn\u011b, p\u0159eposl\u00e1n\u00ed a ARC, postupn\u00e9 zaveden\u00ed.","_seopress_robots_index":"","_seopress_robots_follow":"","_seopress_robots_imageindex":"","_seopress_robots_snippet":"","_seopress_robots_primary_cat":"","_seopress_robots_breadcrumbs":"","_seopress_robots_freeze_modified_date":"","_seopress_robots_custom_modified_date":"","_seopress_robots_canonical":"","_seopress_social_fb_title":"SPF, DKIM a DMARC: co chr\u00e1n\u00ed a co ne | Klytic","_seopress_social_fb_desc":"SPF, DKIM a DMARC vysv\u011btlen\u011b: co kter\u00fd ov\u011b\u0159uje, pro\u010d DMARC neblokuje phishing obecn\u011b, p\u0159eposl\u00e1n\u00ed a ARC, postupn\u00e9 zaveden\u00ed.","_seopress_social_fb_img":"","_seopress_social_fb_img_attachment_id":0,"_seopress_social_fb_img_width":0,"_seopress_social_fb_img_height":0,"_seopress_social_twitter_title":"SPF, DKIM a DMARC: co chr\u00e1n\u00ed a co ne | Klytic","_seopress_social_twitter_desc":"SPF, DKIM a DMARC vysv\u011btlen\u011b: co kter\u00fd ov\u011b\u0159uje, pro\u010d DMARC neblokuje phishing obecn\u011b, p\u0159eposl\u00e1n\u00ed a ARC, postupn\u00e9 zaveden\u00ed.","_seopress_social_twitter_img":"","_seopress_social_twitter_img_attachment_id":0,"_seopress_social_twitter_img_width":0,"_seopress_social_twitter_img_height":0,"_seopress_redirections_value":"","_seopress_redirections_enabled":"","_seopress_redirections_enabled_regex":"","_seopress_redirections_logged_status":"","_seopress_redirections_param":"","_seopress_redirections_type":0,"_seopress_analysis_target_kw":"","_seopress_news_disabled":"","_seopress_video_disabled":"","_seopress_video":[],"_seopress_pro_schemas_manual":[],"_seopress_pro_rich_snippets_disable_all":"","_seopress_pro_rich_snippets_disable":[],"_seopress_pro_schemas":[],"footnotes":""},"class_list":["post-7457","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/eu.klytic.com\/cs\/wp-json\/wp\/v2\/pages\/7457","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/eu.klytic.com\/cs\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/eu.klytic.com\/cs\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/eu.klytic.com\/cs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/eu.klytic.com\/cs\/wp-json\/wp\/v2\/comments?post=7457"}],"version-history":[{"count":0,"href":"https:\/\/eu.klytic.com\/cs\/wp-json\/wp\/v2\/pages\/7457\/revisions"}],"wp:attachment":[{"href":"https:\/\/eu.klytic.com\/cs\/wp-json\/wp\/v2\/media?parent=7457"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}