{"id":363,"date":"2026-08-24T19:56:53","date_gmt":"2026-08-24T19:56:53","guid":{"rendered":"https:\/\/rbl.watch\/blog\/e-posta-sahteciligi-spoofing-nedir-nasil-onlenir\/"},"modified":"2026-08-24T19:56:53","modified_gmt":"2026-08-24T19:56:53","slug":"e-posta-sahteciligi-spoofing-nedir-nasil-onlenir","status":"publish","type":"post","link":"https:\/\/rbl.watch\/blog\/e-posta-sahteciligi-spoofing-nedir-nasil-onlenir\/","title":{"rendered":"E-posta Sahtecili\u011fi (Spoofing) Nedir ve Nas\u0131l \u00d6nlenir? SPF, DKIM, DMARC ile Korunma Rehberi"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">Gelen kutunuza, tam olarak bankan\u0131zdan, patronunuzdan veya kendi \u015firketinizden geliyormu\u015f gibi g\u00f6r\u00fcnen bir e-posta d\u00fc\u015fer \u2014 ama asl\u0131nda bir sald\u0131rgan taraf\u0131ndan g\u00f6nderilmi\u015ftir. Buna <strong>e-posta sahtecili\u011fi (spoofing)<\/strong> denir. SMTP protokol\u00fc g\u00f6nderen adresini do\u011frulamadan tasarland\u0131\u011f\u0131 i\u00e7in, \u00f6nlem al\u0131nmam\u0131\u015f bir alan ad\u0131 ad\u0131na <em>herkes<\/em> sahte e-posta g\u00f6nderebilir. \u0130yi haber: SPF, DKIM ve DMARC ile bu sald\u0131r\u0131lar\u0131n b\u00fcy\u00fck k\u0131sm\u0131n\u0131 durdurabilirsiniz. Bu rehberde spoofing&#8217;in ne oldu\u011funu, t\u00fcrlerini ve katmanl\u0131 korunma y\u00f6ntemlerini anlat\u0131yoruz.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">E-posta Sahtecili\u011fi (Spoofing) Nedir?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">E-posta sahtecili\u011fi, bir sald\u0131rgan\u0131n g\u00f6nderen kimli\u011fini (\u00f6zellikle &#8220;Kimden\/From&#8221; alan\u0131n\u0131) taklit ederek, e-postan\u0131n g\u00fcvenilir bir kaynaktan geliyormu\u015f gibi g\u00f6r\u00fcnmesini sa\u011flamas\u0131d\u0131r. Ama\u00e7 genellikle kurban\u0131 kand\u0131r\u0131p bir ba\u011flant\u0131ya t\u0131klatmak, kimlik bilgisi \u00e7ald\u0131rmak veya sahte bir \u00f6deme\/havale yapt\u0131rmakt\u0131r.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Neden M\u00fcmk\u00fcn?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">SMTP (e-posta g\u00f6nderim protokol\u00fc) 1980&#8217;lerde, g\u00fcvenin varsay\u0131ld\u0131\u011f\u0131 bir internet i\u00e7in tasarland\u0131; g\u00f6nderenin ger\u00e7ekten iddia etti\u011fi ki\u015fi olup olmad\u0131\u011f\u0131n\u0131 do\u011frulayan bir mekanizma i\u00e7ermez. Bu y\u00fczden &#8220;From&#8221; ba\u015fl\u0131\u011f\u0131na istenen her \u015fey yaz\u0131labilir. SPF, DKIM ve DMARC tam da bu eksi\u011fi kapatmak i\u00e7in sonradan eklenen katmanlard\u0131r (bkz. <a href=\"\/blog\/spf-dkim-ve-dmarc-nedir-e-posta-kimlik-dogrulama\/\">SPF\/DKIM\/DMARC rehberi<\/a>).<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Spoofing T\u00fcrleri<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Tam alan ad\u0131 sahtecili\u011fi (exact-domain):<\/strong> From alan\u0131 do\u011frudan sizin alan ad\u0131n\u0131z\u0131 g\u00f6sterir (\u00f6r. <code>muhasebe@sirketiniz.com<\/code>). En tehlikelisidir ama <strong>DMARC ile durdurulabilir<\/strong>.<\/li>\n<li><strong>G\u00f6r\u00fcnen ad sahtecili\u011fi (display name):<\/strong> G\u00f6r\u00fcnen isim &#8220;Genel M\u00fcd\u00fcr&#8221; iken ger\u00e7ek adres rastgele bir Gmail&#8217;dir (<code>Genel M\u00fcd\u00fcr &lt;xyz123@gmail.com&gt;<\/code>). DMARC bunu <em>durdurmaz<\/em>; gateway filtreleme ve kullan\u0131c\u0131 fark\u0131ndal\u0131\u011f\u0131 gerekir.<\/li>\n<li><strong>Benzer alan ad\u0131 (cousin\/lookalike):<\/strong> <code>sirketiniz.com<\/code> yerine <code>sirket\u0131n\u0131z.com<\/code> veya <code>s\u0131rketiniz-tr.com<\/code> gibi g\u00f6z yan\u0131ltan alan adlar\u0131. DMARC kapsam\u0131 d\u0131\u015f\u0131ndad\u0131r; marka izleme ve filtreleme ile ele al\u0131n\u0131r.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Sahtecilik Neden Bu Kadar Tehlikeli?<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Kimlik av\u0131 (phishing):<\/strong> Sahte giri\u015f sayfalar\u0131na y\u00f6nlendirip parola\/kart bilgisi \u00e7alar.<\/li>\n<li><strong>BEC \/ CEO doland\u0131r\u0131c\u0131l\u0131\u011f\u0131:<\/strong> \u00dcst y\u00f6netici gibi g\u00f6r\u00fcn\u00fcp muhasebeye acil &#8220;havale&#8221; talimat\u0131 g\u00f6nderir; kurumlara b\u00fcy\u00fck mali zarar verir.<\/li>\n<li><strong>Marka itibar\u0131:<\/strong> M\u00fc\u015fterilerinize sizin ad\u0131n\u0131za spam\/doland\u0131r\u0131c\u0131l\u0131k gitmesi g\u00fcveni zedeler.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Nas\u0131l \u00d6nlenir? Katmanl\u0131 Savunma<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Tek bir \u00e7\u00f6z\u00fcm her t\u00fcr\u00fc kapatmaz; katmanlar\u0131 birlikte kullan\u0131n:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>SPF + DKIM:<\/strong> Alan ad\u0131n\u0131zdan kimlerin g\u00f6nderebilece\u011fini (SPF) ve mesaj\u0131n yolda de\u011fi\u015fmedi\u011fini (DKIM) tan\u0131mlay\u0131n.<\/li>\n<li><strong>DMARC (en kritik ad\u0131m):<\/strong> Politikan\u0131z\u0131 <a href=\"\/blog\/dmarc-reject-politikasi-ve-blacklist-iliskisi-2026-rehberi\/\">p=reject<\/a>&#8216;e ta\u015f\u0131y\u0131n; bu, <strong>tam alan ad\u0131 sahtecili\u011fini<\/strong> b\u00fcy\u00fck \u00f6l\u00e7\u00fcde durdurur. <a href=\"\/blog\/dmarc-raporlari-nasil-okunur-aggregate-forensic\/\">DMARC raporlar\u0131yla<\/a> alan ad\u0131n\u0131z\u0131n kimler taraf\u0131ndan kullan\u0131ld\u0131\u011f\u0131n\u0131 (ve k\u00f6t\u00fcye kullan\u0131ld\u0131\u011f\u0131n\u0131) g\u00f6r\u00fcrs\u00fcn\u00fcz.<\/li>\n<li><strong>BIMI:<\/strong> DMARC enforcement sonras\u0131, <a href=\"\/blog\/bimi-nedir-eposta-logo-dmarc-vmc-rehberi\/\">BIMI<\/a> ile do\u011frulanm\u0131\u015f logonuzu g\u00f6stererek al\u0131c\u0131ya g\u00f6rsel g\u00fcven verir; sahteciler logonuzu g\u00f6steremez.<\/li>\n<li><strong>Gateway filtreleme:<\/strong> G\u00f6r\u00fcnen ad ve benzer alan ad\u0131 sald\u0131r\u0131lar\u0131 DMARC&#8217;\u0131n d\u0131\u015f\u0131ndad\u0131r; bunlar\u0131 yakalamak i\u00e7in <a href=\"https:\/\/www.ihs.com.tr\/anti-spam\/kangal-eposta-anti-spam.html\" target=\"_blank\" rel=\"noopener\">IHS Kangal E-posta Anti-Spam<\/a> gibi bir g\u00fcvenlik ge\u00e7idi kullan\u0131n.<\/li>\n<li><strong>Kullan\u0131c\u0131 fark\u0131ndal\u0131\u011f\u0131:<\/strong> \u00c7al\u0131\u015fanlar\u0131 &#8220;acil havale&#8221;, tuhaf adresler ve sahte giri\u015f sayfalar\u0131 konusunda e\u011fitin.<\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">Kurumsal g\u00f6nderim ve al\u0131m altyap\u0131n\u0131z\u0131 sa\u011flamla\u015ft\u0131rmak i\u00e7in y\u00f6netilen bir <a href=\"https:\/\/www.ihs.com.tr\/sunucu-kiralama\/exchange-mail-sunucusu.html\" target=\"_blank\" rel=\"noopener\">Exchange mail sunucusu<\/a> da bu katmanlar\u0131 uygulamay\u0131 kolayla\u015ft\u0131r\u0131r.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Alan Ad\u0131n\u0131z Ad\u0131na Sahte E-posta Gidiyor mu? Nas\u0131l Kontrol Edilir?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">\u0130lk ad\u0131m, alan ad\u0131n\u0131z\u0131n sahtecili\u011fe ne kadar a\u00e7\u0131k oldu\u011funu g\u00f6rmektir. <a href=\"\/tools\/e-posta-saglik-kontrolu\">E-posta sa\u011fl\u0131k kontrol\u00fc arac\u0131m\u0131zla<\/a> SPF, DKIM ve DMARC politikan\u0131z\u0131 saniyeler i\u00e7inde denetleyin: DMARC&#8217;\u0131n\u0131z <code>p=none<\/code> ise (veya hi\u00e7 yoksa) alan ad\u0131n\u0131z tam-alan sahtecili\u011fine a\u00e7\u0131kt\u0131r. DMARC raporlar\u0131 ise sizin ad\u0131n\u0131za kimlerin g\u00f6ndermeye \u00e7al\u0131\u015ft\u0131\u011f\u0131n\u0131 ortaya koyar.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">S\u0131k Sorulan Sorular<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">DMARC t\u00fcm spoofing t\u00fcrlerini durdurur mu?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Hay\u0131r. DMARC (p=reject), <strong>tam alan ad\u0131<\/strong> sahtecili\u011fini durdurur; yani From alan\u0131 do\u011frudan sizin alan ad\u0131n\u0131z\u0131 g\u00f6steren sahte mailleri. Ancak g\u00f6r\u00fcnen ad sahtecili\u011fi ve benzer alan ad\u0131 sald\u0131r\u0131lar\u0131n\u0131 durdurmaz \u2014 bunlar i\u00e7in gateway filtreleme ve kullan\u0131c\u0131 fark\u0131ndal\u0131\u011f\u0131 gerekir.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">SPF ve DKIM tek ba\u015f\u0131na yeterli mi?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Hay\u0131r. SPF ve DKIM temel yap\u0131 ta\u015flar\u0131d\u0131r ama sahtecili\u011fi as\u0131l durduran, ikisini bir politikaya ba\u011flayan ve &#8220;ba\u015far\u0131s\u0131z olursa ne yap\u0131ls\u0131n&#8221; diyen DMARC&#8217;t\u0131r. SPF\/DKIM olup DMARC&#8217;\u0131 <code>p=none<\/code> b\u0131rakmak, kap\u0131y\u0131 tak\u0131p kilidini takmamak gibidir.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Alan ad\u0131m hi\u00e7 e-posta g\u00f6ndermiyorsa yine de korunmam gerekir mi?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Kesinlikle. G\u00f6nderim yapmayan alan adlar\u0131 da spoofing i\u00e7in kullan\u0131l\u0131r. Bu t\u00fcr alan adlar\u0131 i\u00e7in &#8220;hi\u00e7 g\u00f6ndermiyorum&#8221; diyen kat\u0131 bir SPF (<code>v=spf1 -all<\/code>) ve <code>p=reject<\/code> DMARC yay\u0131mlayarak ad\u0131n\u0131z\u0131n k\u00f6t\u00fcye kullan\u0131lmas\u0131n\u0131 engelleyin.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>\u00d6zet:<\/strong> E-posta sahtecili\u011fi, SMTP&#8217;nin do\u011fu\u015ftan gelen bir zaaf\u0131ndan beslenir ama modern kimlik do\u011frulama katmanlar\u0131yla b\u00fcy\u00fck \u00f6l\u00e7\u00fcde \u00f6nlenebilir. SPF + DKIM kurun, DMARC&#8217;\u0131 <code>p=reject<\/code>&#8216;e ta\u015f\u0131y\u0131n, BIMI ve gateway filtrelemeyle g\u00fc\u00e7lendirin ve kullan\u0131c\u0131lar\u0131n\u0131z\u0131 e\u011fitin. Ba\u015flamak i\u00e7in alan ad\u0131n\u0131z\u0131 <a href=\"\/tools\/e-posta-saglik-kontrolu\">e-posta sa\u011fl\u0131k kontrol\u00fcnden<\/a> ge\u00e7irin; genel resim i\u00e7in <a href=\"\/blog\/e-posta-teslim-edilebilirlik-nedir-nasil-artirilir\/\">teslim edilebilirlik rehberimize<\/a> bak\u0131n.<\/p>\n\n\n\n<script type=\"application\/ld+json\">\n{\"@context\":\"https:\/\/schema.org\",\"@type\":\"FAQPage\",\"mainEntity\":[\n{\"@type\":\"Question\",\"name\":\"DMARC t\u00fcm spoofing t\u00fcrlerini durdurur mu?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Hay\u0131r. DMARC (p=reject) tam alan ad\u0131 sahtecili\u011fini, yani From alan\u0131 do\u011frudan sizin alan ad\u0131n\u0131z\u0131 g\u00f6steren sahte mailleri durdurur. G\u00f6r\u00fcnen ad sahtecili\u011fi ve benzer alan ad\u0131 sald\u0131r\u0131lar\u0131n\u0131 durdurmaz; bunlar i\u00e7in gateway filtreleme ve kullan\u0131c\u0131 fark\u0131ndal\u0131\u011f\u0131 gerekir.\"}},\n{\"@type\":\"Question\",\"name\":\"SPF ve DKIM tek ba\u015f\u0131na yeterli mi?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Hay\u0131r. SPF ve DKIM temel yap\u0131 ta\u015flar\u0131d\u0131r ama sahtecili\u011fi as\u0131l durduran, ikisini bir politikaya ba\u011flayan DMARC't\u0131r. SPF\/DKIM olup DMARC'\u0131 p=none b\u0131rakmak, kap\u0131y\u0131 tak\u0131p kilidini takmamak gibidir.\"}},\n{\"@type\":\"Question\",\"name\":\"Alan ad\u0131m hi\u00e7 e-posta g\u00f6ndermiyorsa yine de korunmam gerekir mi?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Kesinlikle. G\u00f6nderim yapmayan alan adlar\u0131 da spoofing i\u00e7in kullan\u0131l\u0131r. Bu alan adlar\u0131 i\u00e7in v=spf1 -all kat\u0131 SPF ve p=reject DMARC yay\u0131mlayarak ad\u0131n\u0131z\u0131n k\u00f6t\u00fcye kullan\u0131lmas\u0131n\u0131 engelleyin.\"}}\n]}\n<\/script>\n\n","protected":false},"excerpt":{"rendered":"<p>Gelen kutunuza, tam olarak bankan\u0131zdan, patronunuzdan veya kendi \u015firketinizden geliyormu\u015f gibi g\u00f6r\u00fcnen bir e-posta d\u00fc\u015fer \u2014 ama asl\u0131nda bir sald\u0131rgan taraf\u0131ndan g\u00f6nderilmi\u015ftir. Buna e-posta sahtecili\u011fi (spoofing) denir. SMTP protokol\u00fc g\u00f6nderen adresini do\u011frulamadan tasarland\u0131\u011f\u0131 i\u00e7in, \u00f6nlem al\u0131nmam\u0131\u015f bir alan ad\u0131 ad\u0131na herkes sahte e-posta g\u00f6nderebilir. \u0130yi haber: SPF, DKIM ve DMARC ile bu sald\u0131r\u0131lar\u0131n b\u00fcy\u00fck k\u0131sm\u0131n\u0131 &#8230; <a title=\"E-posta Sahtecili\u011fi (Spoofing) Nedir ve Nas\u0131l \u00d6nlenir? SPF, DKIM, DMARC ile Korunma Rehberi\" class=\"read-more\" href=\"https:\/\/rbl.watch\/blog\/e-posta-sahteciligi-spoofing-nedir-nasil-onlenir\/\" aria-label=\"Read more about E-posta Sahtecili\u011fi (Spoofing) Nedir ve Nas\u0131l \u00d6nlenir? SPF, DKIM, DMARC ile Korunma Rehberi\">Devam\u0131n\u0131 oku<\/a><\/p>\n","protected":false},"author":2,"featured_media":364,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":["post-363","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-eposta-guvenligi"],"_links":{"self":[{"href":"https:\/\/rbl.watch\/blog\/wp-json\/wp\/v2\/posts\/363","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rbl.watch\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rbl.watch\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rbl.watch\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/rbl.watch\/blog\/wp-json\/wp\/v2\/comments?post=363"}],"version-history":[{"count":0,"href":"https:\/\/rbl.watch\/blog\/wp-json\/wp\/v2\/posts\/363\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/rbl.watch\/blog\/wp-json\/wp\/v2\/media\/364"}],"wp:attachment":[{"href":"https:\/\/rbl.watch\/blog\/wp-json\/wp\/v2\/media?parent=363"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rbl.watch\/blog\/wp-json\/wp\/v2\/categories?post=363"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rbl.watch\/blog\/wp-json\/wp\/v2\/tags?post=363"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}