{"id":709,"date":"2026-07-08T04:14:57","date_gmt":"2026-07-08T04:14:57","guid":{"rendered":"https:\/\/rufreevpn.org\/"},"modified":"2026-07-08T04:14:57","modified_gmt":"2026-07-08T04:14:57","slug":"demystifying-l2tp","status":"publish","type":"post","link":"https:\/\/rufreevpn.org\/tr\/post\/demystifying-l2tp\/","title":{"rendered":"L2TP'yi Anlamak: Katman 2 T\u00fcnelleme Protokol\u00fcn\u00fcn Arkas\u0131ndaki Mimari"},"content":{"rendered":"

Sanal \u00f6zel a\u011f olu\u015fturman\u0131n evrimsel zaman \u00e7izelgesinde, L2TP (Katman 2 T\u00fcnel Protokol\u00fc), eski \u00e7evirmeli a\u011f altyap\u0131lar\u0131 ile modern kriptografik g\u00fcvenlik aras\u0131nda kritik bir k\u00f6pr\u00fc olarak durmaktad\u0131r. Resmi olarak RFC 2661'de tan\u0131mlanan L2TP, iki eski \u00e7er\u00e7evenin en iyi \u00f6zelliklerini birle\u015ftiren bir oturum katman\u0131 protokol\u00fcd\u00fcr: Microsoft\u2019un PPTP'si (Noktadan Noktaya T\u00fcnel Protokol\u00fc) ve Cisco\u2019nun L2F'si (Katman 2 Y\u00f6nlendirme).<\/p>\n\n\n\n

\"L2TP\"<\/figure>\n\n\n\n

OSI modelinin Veri Ba\u011flant\u0131 Katman\u0131'nda (Katman 2) \u00e7al\u0131\u015fan L2TP'nin birincil amac\u0131, Noktadan Noktaya Protokol (PPP) \u00e7er\u00e7evelerini IP, Frame Relay veya ATM gibi paket anahtarlamal\u0131 a\u011flar \u00fczerinden ta\u015f\u0131nabilmeleri i\u00e7in kaps\u00fcllemektir.<\/p>\n\n\n\n

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\u26a0\ufe0f \u015eeffafl\u0131k Paradoksu<\/h3>\n\n\n\n

Tamamen g\u00fcvenlik denetimi perspektifinden bak\u0131ld\u0131\u011f\u0131nda, L2TP teknik olarak \u015feffaft\u0131r. Sanal otoyolu in\u015fa eder ancak z\u0131rhl\u0131 arac\u0131 sa\u011flamaz; herhangi bir yerel veri \u015fifrelemesi veya kaynak kimlik do\u011frulama mekanizmas\u0131na sahip de\u011fildir. Ta\u015f\u0131ma s\u0131ras\u0131nda veriyi korumak i\u00e7in neredeyse evrensel olarak \u0130nternet Protokol\u00fc G\u00fcvenlik \u00e7er\u00e7evesiyle birle\u015ftirilir ve L2TP\/IPsec paketini olu\u015fturur.<\/p>\n<\/blockquote>\n\n\n\n

Bir L2TP Ba\u011flant\u0131s\u0131n\u0131n Anatomisi: LAC'den LNS'ye<\/h2>\n\n\n\n

L2TP'nin co\u011frafi b\u00f6l\u00fcnmeleri nas\u0131l birle\u015ftirdi\u011fini anlamak i\u00e7in, onun iki temel mimari u\u00e7 noktas\u0131n\u0131 anlamal\u0131s\u0131n\u0131z:<\/p>\n\n\n\n

    \n
  • LAC (L2TP Eri\u015fim Yo\u011funla\u015ft\u0131r\u0131c\u0131):<\/strong> T\u00fcnel ba\u015flat\u0131c\u0131s\u0131. Bu, yerel bir ba\u011flant\u0131y\u0131 fiziksel olarak sonland\u0131ran ve trafi\u011fi L2TP t\u00fcneline y\u00f6nlendiren cihazd\u0131r (bir ISP a\u011f eri\u015fim sunucusu veya yerel istemci gibi).<\/li>\n\n\n\n
  • LNS (L2TP A\u011f Sunucusu):<\/strong> T\u00fcnelin al\u0131c\u0131s\u0131 ve mant\u0131ksal sonland\u0131rma noktas\u0131. LNS, gelen L2TP paketlerinin kaps\u00fcl\u00fcn\u00fc a\u00e7ar, orijinal PPP \u00e7er\u00e7evelerini \u00e7\u0131kar\u0131r ve uzak kullan\u0131c\u0131y\u0131 yerel kurumsal a\u011fa entegre eder.<\/li>\n<\/ul>\n\n\n\n
    \n

    How Data Moves Through L2TP\/IPsec<\/h3>\n \n
    \n
    Kullan\u0131c\u0131 Cihaz\u0131<\/span><\/div>\n
    1. PPP Frame Created<\/span>\u27a1\ufe0f<\/div>\n
    L2TP Encapsulation<\/span><\/div>\n
    2. IPsec Armor Attached<\/span>\u27a1\ufe0f<\/div>\n
    UDP T\u00fcneli<\/span><\/div>\n
    \u27a1\ufe0f<\/div>\n
    VPN Sunucusu \/ LNS<\/span><\/div>\n <\/div>\n\n
    \n
    \n
    01<\/div>\n
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    Ba\u015flatma & T\u00fcnelleme<\/h4>\n

    The client device packages traffic into standard PPP frames. The LAC wraps these frames inside an L2TP header.<\/p>\n <\/div>\n <\/div>\n \n

    \n
    02<\/div>\n
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    Kriptografik Sarma (IPsec)<\/h4>\n

    L2TP paketi a\u00e7\u0131kta oldu\u011fu i\u00e7in IPsec onu keser. Kaps\u00fcll\u00fc G\u00fcvenlik Y\u00fck\u00fc (ESP) kullanarak IPsec, t\u00fcm L2TP paketini \u015fifreler ve veri b\u00fct\u00fcnl\u00fc\u011f\u00fc i\u00e7in imzalar.<\/p>\n <\/div>\n <\/div>\n \n

    \n
    03<\/div>\n
    \n

    Transit<\/h4>\n

    Paket, 1701, 500 veya 4500 portlar\u0131n\u0131 kullanarak genel y\u00f6nlendirme altyap\u0131s\u0131 \u00fczerinden UDP ile g\u00f6nderilir.<\/p>\n <\/div>\n <\/div>\n \n

    \n
    04<\/div>\n
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    LNS'de dekaps\u00fclasyon<\/h4>\n

    LNS, paketi al\u0131r, IPsec kullanarak \u015fifresini \u00e7\u00f6zer ve kayna\u011f\u0131n\u0131 do\u011frular, L2TP ta\u015f\u0131ma ba\u015fl\u0131\u011f\u0131n\u0131 kald\u0131r\u0131r ve temiz PPP verilerini hedef \u00f6zel a\u011fa iletir.<\/p>\n <\/div>\n <\/div>\n <\/div>\n<\/div>\n\n