{"id":8169,"date":"2026-10-18T11:57:48","date_gmt":"2026-10-18T09:57:48","guid":{"rendered":"https:\/\/eu.it-cyberwall.com\/guides\/spf-dkim-e-dmarc-proteger-o-e-mail-de-uma-pme\/"},"modified":"2026-10-18T20:38:15","modified_gmt":"2026-10-18T18:38:15","slug":"spf-dkim-dmarc","status":"publish","type":"page","link":"https:\/\/eu.it-cyberwall.com\/pt-pt\/guides\/spf-dkim-dmarc\/","title":{"rendered":"SPF, DKIM e DMARC: proteger o e-mail de uma PME"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-page\" data-elementor-id=\"8169\" class=\"elementor elementor-8169 elementor-6679\" data-elementor-settings=\"{&quot;ha_cmc_init_switcher&quot;:&quot;no&quot;}\" data-elementor-post-type=\"page\">\n\t\t\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-36a12c3 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"36a12c3\" data-element_type=\"section\" data-e-type=\"section\" data-settings=\"{&quot;_ha_eqh_enable&quot;:false}\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-a39c058\" data-id=\"a39c058\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-3c2a2db elementor-widget elementor-widget-html\" data-id=\"3c2a2db\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"html.default\">\n\t\t\t\t\t<style>.itcw-g{max-width:900px;margin:0 auto;font-size:17px;line-height:1.65;color:#2b2f3a}.itcw-g h2{margin-top:10px}.itcw-g .tw{overflow-x:auto;margin:18px 0}.itcw-g table{width:100%;border-collapse:collapse;font-size:15px;min-width:640px}.itcw-g th,.itcw-g td{border:1px solid #e3e6ee;padding:10px 12px;vertical-align:top;text-align:left}.itcw-g thead th{background:#0E0129;color:#fff}.itcw-g tbody th{background:#F6F7FA;font-weight:600}.itcw-g .box{background:#F6F7FA;border-left:4px solid #DE3241;padding:16px 20px;border-radius:6px;margin:18px 0}.itcw-g .box.ok{border-left-color:#2C9703}.itcw-g sup a{text-decoration:none;font-weight:600}.itcw-g ol.src li{margin-bottom:8px;font-size:15px;word-break:break-word}.itcw-g .note{font-size:14px;color:#6b7080}.itcw-g .toc a{display:inline-block;margin:4px 10px 4px 0}<\/style>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-4f9122d elementor-widget elementor-widget-heading\" data-id=\"4f9122d\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h6 class=\"elementor-heading-title elementor-size-default\">Guia<\/h6>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-9972963 elementor-widget elementor-widget-heading\" data-id=\"9972963\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h1 class=\"elementor-heading-title elementor-size-default\">SPF, DKIM e DMARC: proteger o e-mail de uma PME<\/h1>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-2026230 elementor-widget elementor-widget-text-editor\" data-id=\"2026230\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<div class=\"itcw-g\"><p style=\"text-align:center\">O SPF, o DKIM e o DMARC impedem que sejam enviados e-mails falsos em seu nome e ajudam as suas mensagens verdadeiras a chegar ao destino. A Google, a Yahoo e a Microsoft j\u00e1 os exigem aos grandes remetentes. Eis o que fazem, explicado de forma clara, e como os implementar sem bloquear as suas pr\u00f3prias faturas.<\/p><p class=\"note\" style=\"text-align:center\">Atualizado a 18 de outubro de 2026 \u00b7 Os n\u00fameros t\u00eam as fontes indicadas no fundo da p\u00e1gina; as aprecia\u00e7\u00f5es s\u00e3o da IT CyberWall.<\/p><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-16c50dd elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"16c50dd\" data-element_type=\"section\" data-e-type=\"section\" data-settings=\"{&quot;_ha_eqh_enable&quot;:false}\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-7b83a94\" data-id=\"7b83a94\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-731364b elementor-widget elementor-widget-text-editor\" data-id=\"731364b\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<div class=\"itcw-g\"><div class=\"box toc\"><strong>Neste guia:<\/strong><br \/><a href=\"#pourquoi\">Porque \u00e9 um assunto seu<\/a> \u00b7 <a href=\"#trois\">SPF, DKIM e DMARC explicados<\/a> \u00b7 <a href=\"#exigences\">O que a Google, a Yahoo e a Microsoft exigem<\/a> \u00b7 <a href=\"#etapes\">A implementa\u00e7\u00e3o, passo a passo<\/a> \u00b7 <a href=\"#it-cyberwall\">O que a IT CyberWall faz<\/a> \u00b7 <a href=\"#sources\">Fontes<\/a><\/div><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-2124b50 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"2124b50\" data-element_type=\"section\" data-e-type=\"section\" id=\"pourquoi\" data-settings=\"{&quot;_ha_eqh_enable&quot;:false}\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-f7bf464\" data-id=\"f7bf464\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-bcf5c8e elementor-widget elementor-widget-heading\" data-id=\"bcf5c8e\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Porque \u00e9 um assunto seu<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-b9865c6 elementor-widget elementor-widget-text-editor\" data-id=\"b9865c6\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<div class=\"itcw-g\"><p>Qualquer pessoa pode enviar um e-mail que parece vir do seu dom\u00ednio: uma fatura falsa aos seus clientes, uma ordem de transfer\u00eancia falsa ao seu contabilista. Tr\u00eas configura\u00e7\u00f5es, publicadas no DNS do seu nome de dom\u00ednio, permitem aos servi\u00e7os de e-mail dos seus destinat\u00e1rios reconhecer as suas mensagens verdadeiras. Protegem o seu e-mail e a sua reputa\u00e7\u00e3o, n\u00e3o os seus dados: n\u00e3o s\u00e3o uma c\u00f3pia de seguran\u00e7a.<\/p><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-7688241 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"7688241\" data-element_type=\"section\" data-e-type=\"section\" id=\"trois\" data-settings=\"{&quot;background_background&quot;:&quot;classic&quot;,&quot;_ha_eqh_enable&quot;:false}\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-5e862c2\" data-id=\"5e862c2\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-605ce07 elementor-widget elementor-widget-heading\" data-id=\"605ce07\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">SPF, DKIM e DMARC explicados<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-0210b77 elementor-widget elementor-widget-text-editor\" data-id=\"0210b77\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<div class=\"itcw-g\"><table><thead><tr><th>Configura\u00e7\u00e3o<\/th><th>O que diz<\/th><th>Imagem<\/th><\/tr><\/thead><tbody><tr><td><strong>SPF<\/strong><\/td><td>A lista dos servidores autorizados a enviar mensagens em nome do seu dom\u00ednio<sup><a href=\"#source-1\">[1]<\/a><\/sup>.<\/td><td>A lista dos carteiros autorizados.<\/td><\/tr><tr><td><strong>DKIM<\/strong><\/td><td>Uma assinatura digital acrescentada a cada mensagem, que liga a mensagem ao seu dom\u00ednio<sup><a href=\"#source-2\">[2]<\/a><\/sup>.<\/td><td>O carimbo da empresa no envelope.<\/td><\/tr><tr><td><strong>DMARC<\/strong><\/td><td>A sua instru\u00e7\u00e3o aos destinat\u00e1rios quando uma mensagem falha os controlos (n\u00e3o fazer nada, colocar no spam, rejeitar) e o envio de relat\u00f3rios<sup><a href=\"#source-3\">[3]<\/a><\/sup>.<\/td><td>A instru\u00e7\u00e3o deixada na rece\u00e7\u00e3o.<\/td><\/tr><\/tbody><\/table><p>A ANSSI dedica a estes tr\u00eas mecanismos uma parte das suas recomenda\u00e7\u00f5es sobre a interliga\u00e7\u00e3o de um sistema de informa\u00e7\u00e3o \u00e0 internet<sup><a href=\"#source-4\">[4]<\/a><\/sup>.<\/p><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-172d405 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"172d405\" data-element_type=\"section\" data-e-type=\"section\" id=\"exigences\" data-settings=\"{&quot;_ha_eqh_enable&quot;:false}\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-8ec4a9f\" data-id=\"8ec4a9f\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-eeb7820 elementor-widget elementor-widget-heading\" data-id=\"eeb7820\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">O que a Google, a Yahoo e a Microsoft exigem<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-a305bee elementor-widget elementor-widget-text-editor\" data-id=\"a305bee\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<div class=\"itcw-g\"><ul><li><strong>Google<\/strong>, desde 1 de fevereiro de 2024: SPF ou DKIM para todos os remetentes; SPF, DKIM e DMARC para quem envia mais de 5 000 mensagens por dia para o Gmail<sup><a href=\"#source-5\">[5]<\/a><\/sup>.<\/li><li><strong>Yahoo<\/strong>: SPF ou DKIM para todos; SPF, DKIM e DMARC para os envios em massa<sup><a href=\"#source-6\">[6]<\/a><\/sup>.<\/li><li><strong>Microsoft Outlook.com<\/strong>, desde 5 de maio de 2025: SPF, DKIM e DMARC para os dom\u00ednios que enviam mais de 5 000 mensagens por dia; caso contr\u00e1rio, as mensagens v\u00e3o para o spam e, depois, s\u00e3o rejeitadas<sup><a href=\"#source-7\">[7]<\/a><\/sup>.<\/li><\/ul><p>Mesmo uma PME que envia poucas mensagens tem interesse em publicar os tr\u00eas: as suas faturas e or\u00e7amentos chegam melhor ao destino e o seu nome torna-se mais dif\u00edcil de usurpar.<\/p><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-b5d71c9 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"b5d71c9\" data-element_type=\"section\" data-e-type=\"section\" id=\"etapes\" data-settings=\"{&quot;background_background&quot;:&quot;classic&quot;,&quot;_ha_eqh_enable&quot;:false}\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-4f5562a\" data-id=\"4f5562a\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-572b83d elementor-widget elementor-widget-heading\" data-id=\"572b83d\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">A implementa\u00e7\u00e3o, passo a passo<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-a32de41 elementor-widget elementor-widget-text-editor\" data-id=\"a32de41\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<div class=\"itcw-g\"><ol><li><strong>Identificar tudo o que envia mensagens em seu nome<\/strong>: e-mail, software de fatura\u00e7\u00e3o, CRM, website, ferramenta de e-mailing, impressora que envia digitaliza\u00e7\u00f5es.<\/li><li><strong>Publicar um SPF<\/strong> que liste estes remetentes, sem esquecer nenhum.<\/li><li><strong>Ativar o DKIM<\/strong> em cada servi\u00e7o que o permita.<\/li><li><strong>Publicar um DMARC em observa\u00e7\u00e3o<\/strong> (pol\u00edtica \u00abnone\u00bb) e receber os relat\u00f3rios.<\/li><li><strong>Ler os relat\u00f3rios<\/strong> durante algumas semanas: revelam os remetentes esquecidos e as usurpa\u00e7\u00f5es.<\/li><li><strong>Refor\u00e7ar progressivamente<\/strong>: envio para spam (\u00abquarantine\u00bb) e, depois, rejei\u00e7\u00e3o (\u00abreject\u00bb), que a Microsoft recomenda<sup><a href=\"#source-7\">[7]<\/a><\/sup>.<\/li><\/ol><div class=\"box\"><strong>A armadilha.<\/strong> Passar diretamente para a rejei\u00e7\u00e3o sem ter identificado os seus remetentes bloqueia as suas pr\u00f3prias faturas. A etapa de observa\u00e7\u00e3o n\u00e3o \u00e9 facultativa.<\/div><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-b863dc0 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"b863dc0\" data-element_type=\"section\" data-e-type=\"section\" id=\"it-cyberwall\" data-settings=\"{&quot;_ha_eqh_enable&quot;:false}\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-54437ee\" data-id=\"54437ee\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-5a17ad7 elementor-widget elementor-widget-heading\" data-id=\"5a17ad7\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">O que a IT CyberWall faz<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-9b2a2f2 elementor-widget elementor-widget-text-editor\" data-id=\"9b2a2f2\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<div class=\"itcw-g\"><p>Fazemos o invent\u00e1rio dos seus remetentes, publicamos e testamos os registos SPF, DKIM e DMARC, lemos os relat\u00f3rios consigo e refor\u00e7amos a pol\u00edtica quando isso n\u00e3o tem risco. \u00c9 uma interven\u00e7\u00e3o curta, que se integra nos nossos servi\u00e7os de <a href=\"https:\/\/eu.it-cyberwall.com\/pt-pt\/cybersecurite\/\">ciberseguran\u00e7a<\/a>.<\/p><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-5735d54 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"5735d54\" data-element_type=\"section\" data-e-type=\"section\" data-settings=\"{&quot;background_background&quot;:&quot;classic&quot;,&quot;_ha_eqh_enable&quot;:false}\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-f5cc4d7\" data-id=\"f5cc4d7\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-06b9d29 elementor-widget elementor-widget-heading\" data-id=\"06b9d29\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Os seus e-mails v\u00e3o parar ao spam ou o seu nome est\u00e1 a ser usurpado?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-0aefcda elementor-widget elementor-widget-text-editor\" data-id=\"0aefcda\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<p>Verificamos os seus registos e implementamos o SPF, o DKIM e o DMARC.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-7bba935 elementor-align-center elementor-widget elementor-widget-button\" data-id=\"7bba935\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"button.default\">\n\t\t\t\t\t\t\t\t\t\t<a class=\"elementor-button elementor-button-link elementor-size-md\" href=\"https:\/\/eu.it-cyberwall.com\/pt-pt\/contact\/?mf-besoin=cybersecurite#formulaire\">\n\t\t\t\t\t\t<span class=\"elementor-button-content-wrapper\">\n\t\t\t\t\t\t<span class=\"elementor-button-icon\">\n\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-arrow-right\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M190.5 66.9l22.2-22.2c9.4-9.4 24.6-9.4 33.9 0L441 239c9.4 9.4 9.4 24.6 0 33.9L246.6 467.3c-9.4 9.4-24.6 9.4-33.9 0l-22.2-22.2c-9.5-9.5-9.3-25 .4-34.3L311.4 296H24c-13.3 0-24-10.7-24-24v-32c0-13.3 10.7-24 24-24h287.4L190.9 101.2c-9.8-9.3-10-24.8-.4-34.3z\"><\/path><\/svg>\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t<span class=\"elementor-button-text\">Descrever a minha necessidade<\/span>\n\t\t\t\t\t<\/span>\n\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-82059e2 elementor-widget elementor-widget-text-editor\" data-id=\"82059e2\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<p><a href=\"https:\/\/eu.it-cyberwall.com\/pt-pt\/guides\/\">\u2190 Todos os nossos guias<\/a><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-12a1db7 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"12a1db7\" data-element_type=\"section\" data-e-type=\"section\" id=\"sources\" data-settings=\"{&quot;_ha_eqh_enable&quot;:false}\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-e58afdb\" data-id=\"e58afdb\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-1eeb08b elementor-widget elementor-widget-heading\" data-id=\"1eeb08b\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Fontes<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-7caf600 elementor-widget elementor-widget-text-editor\" data-id=\"7caf600\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<div class=\"itcw-g\"><p class=\"note\">Fontes consultadas a 18 de outubro de 2026. Os pre\u00e7os dos fornecedores s\u00e3o indicados sem IVA, na moeda e na regi\u00e3o da tabela publicada, e podem mudar: confirme sempre a p\u00e1gina oficial antes de decidir.<\/p><ol class=\"src\"><li id=\"source-1\">IETF \u2013 RFC 7208, Sender Policy Framework (SPF), abril de 2014 \u2014 <a href=\"https:\/\/www.rfc-editor.org\/rfc\/rfc7208\" target=\"_blank\" rel=\"noopener\">www.rfc-editor.org\/rfc\/rfc7208<\/a><\/li><li id=\"source-2\">IETF \u2013 RFC 6376, DomainKeys Identified Mail (DKIM) Signatures, setembro de 2011 \u2014 <a href=\"https:\/\/www.rfc-editor.org\/rfc\/rfc6376\" target=\"_blank\" rel=\"noopener\">www.rfc-editor.org\/rfc\/rfc6376<\/a><\/li><li id=\"source-3\">IETF \u2013 RFC 9989, DMARC (maio de 2026, substitui a RFC 7489) \u2014 <a href=\"https:\/\/www.rfc-editor.org\/rfc\/rfc9989\" target=\"_blank\" rel=\"noopener\">www.rfc-editor.org\/rfc\/rfc9989<\/a><\/li><li id=\"source-4\">ANSSI \u2013 Recommandations relatives \u00e0 l\u2019interconnexion d\u2019un syst\u00e8me d\u2019information \u00e0 internet, v3.0 (19 de junho de 2020), \u00a7 5.4 \u2014 <a href=\"https:\/\/messervices.cyber.gouv.fr\/guides\/recommandations-relatives-linterconnexion-dun-si-internet\" target=\"_blank\" rel=\"noopener\">messervices.cyber.gouv.fr\/guides\/recommandations-relatives-linterconnexion-dun-si-internet<\/a><\/li><li id=\"source-5\">Google \u2013 Consignes pour les exp\u00e9diteurs de messages \u2014 <a href=\"https:\/\/support.google.com\/a\/answer\/81126?hl=fr\" target=\"_blank\" rel=\"noopener\">support.google.com\/a\/answer\/81126?hl=fr<\/a><\/li><li id=\"source-6\">Yahoo \u2013 Sender Best Practices \u2014 <a href=\"https:\/\/senders.yahooinc.com\/best-practices\/\" target=\"_blank\" rel=\"noopener\">senders.yahooinc.com\/best-practices\/<\/a><\/li><li id=\"source-7\">Microsoft \u2013 Outlook.com Policies, Practices, and Guidelines \u2014 <a href=\"https:\/\/substrate.office.com\/ip-domain-management-snds\/Postmaster\/Policies\" target=\"_blank\" rel=\"noopener\">substrate.office.com\/ip-domain-management-snds\/Postmaster\/Policies<\/a><\/li><\/ol><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":0,"parent":8066,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_seopress_titles_title":"SPF, DKIM e DMARC para PME europeias | IT CyberWall","_seopress_titles_desc":"SPF, DKIM e DMARC explicados de forma simples, requisitos da Google, Yahoo e Microsoft e implementa\u00e7\u00e3o passo a passo para o e-mail das PME na 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dkim dmarc,configurar dmarc b\u00e9lgica,proteger email empresarial europa,falsifica\u00e7\u00e3o de endere\u00e7o de 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