{"id":707,"date":"2020-04-13T13:41:48","date_gmt":"2020-04-13T11:41:48","guid":{"rendered":"http:\/\/tech.sosthe.sk\/?page_id=707"},"modified":"2020-04-13T13:41:48","modified_gmt":"2020-04-13T11:41:48","slug":"wake-on-lan","status":"publish","type":"page","link":"http:\/\/tech.sosthe.sk\/index.php\/odborne-predmety\/pocitacove-systemy\/wake-on-lan\/","title":{"rendered":"Wake on LAN"},"content":{"rendered":"

Wake on LAN<\/span><\/strong>\u00a0(WOL) funguje na\u00a0<\/span>Ethernete<\/span><\/em><\/strong> a je nez\u00e1visl\u00fd na pou\u017e\u00edvanom protokole (TCP\/IP, IPX \u010di in\u00fd). Ako n\u00e1zov napoved\u00e1, tak budenie funguje v r\u00e1mci <\/span>lok\u00e1lnej siete<\/span><\/em>.\u00a0<\/span>LAN<\/span><\/strong>\u00a0predt\u00fdm predstavoval\u00a0<\/span>jeden subnet<\/span><\/em><\/strong>, tak\u017ee v\u0161etko bolo jednoduch\u00e9 a \u010falej je pop\u00edsan\u00e9 v prvej variante.\u00a0Dnes je v\u0161ak\u00a0<\/span>lok\u00e1lna sie\u0165<\/span><\/em>\u00a0ve\u013emi \u010dasto delen\u00e1 do\u00a0<\/span>rady subnetov<\/span><\/em><\/strong>\u00a0a ako LAN sa ozna\u010duje zemepisn\u00e1 poloha.\u00a0Tak\u017ee sa WOL rie\u0161i do in\u00e9ho subnetu, ob\u010das sa ozna\u010duje ako\u00a0<\/span>WOL over the internet<\/span><\/em><\/strong>, a t\u00fato situ\u00e1ciu popisujem v \u010fal\u0161\u00edch variantoch.<\/span><\/p>\n

Pozn .:<\/em><\/strong>\u00a0V \u010dl\u00e1nku rozli\u010dne pou\u017e\u00edvam term\u00edny\u00a0r\u00e1mec<\/em><\/strong>\u00a0(frame) a\u00a0paket<\/em><\/strong>\u00a0(packet), \u010dasto (nie v\u017edy) sa daj\u00fa zameni\u0165, z\u00e1le\u017e\u00ed na tom, \u010di n\u00e1s v danom kontexte zauj\u00edmaj\u00fa aj MAC adresy alebo iba IP adresy a vy\u0161\u0161ie.<\/span><\/p>\n

\u010co mus\u00ed sp\u013a\u0148a\u0165 klient – zapnutie WOL<\/span><\/h3>\n

Najprv za\u010dnem t\u00fdm, \u010do mus\u00ed sp\u013a\u0148a\u0165\u00a0<\/span>klient<\/span><\/em><\/strong>, teda buden\u00fd po\u010d\u00edta\u010d, aby ho bolo mo\u017en\u00e9\u00a0<\/span>vzdialene zapn\u00fa\u0165<\/span><\/em><\/strong>\u00a0.<\/span><\/p>\n

Je potreba podpora u\u00a0<\/span>z\u00e1kladnej dosky<\/span><\/em><\/strong> a u\u00a0<\/span>sie\u0165ovej karty<\/span><\/em><\/strong>\u00a0(NIC).\u00a0Funguje to tak, \u017ee aj ke\u010f je po\u010d\u00edta\u010d vypnut\u00fd, tak sie\u0165ov\u00e1 karta je st\u00e1le nap\u00e1jan\u00e1 a po\u010d\u00fava komunik\u00e1ciu, \u010di nepri\u0161iel \u0161peci\u00e1lne r\u00e1mec (frame), ktor\u00fd sa vol\u00e1\u00a0<\/span>Magic Packet<\/span><\/em><\/strong>.\u00a0Sie\u0165ov\u00e1 karta pracuje v \u0161peci\u00e1lnom re\u017eime\u00a0<\/span>Magic Packet Mode<\/span><\/em><\/strong>.\u00a0Vo chv\u00edli, ke\u010f zachyt\u00ed\u00a0<\/span>Magic Packet<\/span><\/em>, ktor\u00fd je ur\u010den\u00fd pre \u0148u (pod\u013ea MAC adresy, vi\u010f \u010falej), tak po\u0161le sign\u00e1l z\u00e1kladnej doske, aby zapla po\u010d\u00edta\u010d.<\/span><\/p>\n

Predt\u00fdm sa pre\u00a0<\/span>extern\u00e9 sie\u0165ov\u00e9 karty<\/span><\/em><\/strong> pou\u017e\u00edval \u0161peci\u00e1lny k\u00e1bel, ktor\u00fd ju sp\u00e1jal so z\u00e1kladnou doskou. Nesk\u00f4r sa tento budiaci sign\u00e1l za\u010dal posiela\u0165 po\u00a0<\/span>PCI zbernici<\/span><\/em><\/strong>\u00a0(od verzie PCI 2.2).\u00a0Dnes m\u00e1me sie\u0165ov\u00fa kartu integrovan\u00fa na z\u00e1kladnej doske, tak\u017ee je v\u0161etko jednoduch\u0161ie (ale rovnako to v skuto\u010dnosti funguje po PCI alebo PCIe).<\/span><\/p>\n

V\u00e4\u010d\u0161inou sta\u010d\u00ed v\u00a0\u00a0<\/span>BIOSe<\/span><\/strong>\u00a0zapn\u00fa\u0165 funkciu\u00a0<\/span>Wake On LAN<\/span><\/em><\/strong>, ktor\u00e1 b\u00fdva nazvan\u00e1 r\u00f4zne, napr\u00edklad na mojej dom\u00e1cej z\u00e1kladnej doske sa skr\u00fdva v\u00a0\u00a0<\/span>AMI BIOSe<\/span><\/em><\/strong>\u00a0pod\u00a0<\/span>Power – APM Configuration – Power On By PCIE Device<\/span><\/em><\/strong>, preto\u017ee integrovan\u00e1 sie\u0165ov\u00e1 karta je na PCI Express zbernicu.<\/span><\/p>\n

Niekedy je potrebn\u00e9 e\u0161te nastavi\u0165 sie\u0165ov\u00fa kartu, \u010do m\u00f4\u017eeme urobi\u0165 z Windows pod\u00a0<\/span>Control\u00a0<\/span><\/em><\/strong>Panel – System – Hardware – Device Manager –\u00a0<\/span><\/em><\/strong>dan\u00fd sie\u0165ov\u00fd adapt\u00e9r – Properties – Advanced<\/span><\/em><\/strong>\u00a0– tu nastavenie\u00a0<\/span>Wake Up Capabilities<\/span><\/em><\/strong>, pr\u00edpadne e\u0161te\u00a0<\/span>Wake From Shutdown<\/span><\/em><\/strong>\u00a0.<\/span><\/p>\n

D\u00f4le\u017eit\u00e9 je, \u017ee \u0161tandardne mus\u00ed by\u0165 sie\u0165ov\u00e1 karta prepnut\u00e1 do \u0161peci\u00e1lneho re\u017eimu\u00a0<\/span>Magic Packet Mode<\/span><\/em><\/strong>\u00a0(to sa prevedie nastaven\u00edm bitu v internom registri), kedy kontroluje sie\u0165ov\u00fa prev\u00e1dzku, \u010di nepri\u0161iel\u00a0<\/span>Magic Packet<\/span><\/em><\/strong>.\u00a0To dosiahneme korektn\u00fdm vypnut\u00edm po\u010d\u00edta\u010da (pri zapnut\u00ed sa tento \u0161peci\u00e1lny m\u00f3d automaticky vypne), niekde sa tomu hovor\u00ed <\/span>Soft Shutdown<\/span><\/em><\/strong>.\u00a0K tomu ned\u00f4jde napr\u00edklad pri preru\u0161en\u00ed dod\u00e1vky elektrickej energie alebo pri vypnut\u00ed po\u010d\u00edta\u010da dlh\u00fdm podr\u017ean\u00edm\u00a0<\/span>Power Button<\/span><\/em>.\u00a0V\u0161etko e\u0161te z\u00e1le\u017e\u00ed na tom, \u010di do <\/span>Magic Packet Mode<\/span><\/em><\/strong>\u00a0 prep\u00edna\u00a0 <\/span>ovl\u00e1da\u010d sie\u0165ovej karty<\/span><\/em><\/strong>, potom v\u0161etko mus\u00ed by\u0165 nastaven\u00e9 v tomto ovl\u00e1da\u010di a opera\u010dn\u00fd syst\u00e9m mus\u00ed by\u0165 korektne ukon\u010den\u00fd.\u00a0Alebo je to rie\u0161en\u00e9 v\u00a0\u00a0<\/span>hardv\u00e9ri<\/span><\/em><\/strong> \u010di\u00a0<\/span>BIOSe<\/span><\/em><\/strong>\u00a0.<\/span><\/p>\n

Pozn .:<\/em><\/strong>\u00a0To, \u017ee je sie\u0165ov\u00e1 karta nap\u00e1jan\u00e1 aj pri vypnutom po\u010d\u00edta\u010di pozn\u00e1me pod\u013ea toho, \u017ee m\u00e1 st\u00e1le\u00a0link state<\/em><\/strong>\u00a0(svieti di\u00f3da na sie\u0165ovej karte aj na porte switche, na switchi sa hl\u00e1si ako connected).<\/span><\/p>\n

 <\/p>\n

Z\u00e1kladn\u00fd princ\u00edp WOL – Magic Packet<\/span><\/h3>\n

Wake on LAN<\/span><\/strong>\u00a0funguje tak, \u017ee z nejakej riadiacej stanice odo\u0161leme \u0161peci\u00e1lny r\u00e1mec (frame) tzv.\u00a0<\/span>Magic Packet<\/span><\/em><\/strong>.\u00a0<\/span>Magic Packet<\/span><\/em><\/strong>\u00a0je \u0161tandardn\u00fd r\u00e1mec, ktor\u00fd obsahuje\u00a0<\/span>zdrojov\u00fa adresu<\/span><\/em><\/strong>,\u00a0<\/span>cie\u013eov\u00fa adresu<\/span><\/em><\/strong>, ktor\u00e1 m\u00f4\u017ee by\u0165 adresou cie\u013eovej stanice alebo\u00a0<\/span>multicastovej<\/span><\/em><\/strong> (tzn. aj <\/span>broadcastovej<\/span><\/em><\/strong> ) adresy. D\u00e1tov\u00fd obsah paketu mus\u00ed kdeko\u013evek vo vn\u00fatri (ale v\u00e4\u010d\u0161inou tu in\u00fd obsah nie je) obsahova\u0165\u00a0<\/span>synhroniza\u010dn\u00fd stream<\/span><\/em><\/strong>, \u010do je\u00a0<\/span>6 bytov o hodnote FF<\/span><\/strong>.\u00a0Nasledovan\u00fd\u00a0<\/span>16 kr\u00e1t<\/span><\/em><\/strong> zopakovanou <\/span>MAC adresou<\/span><\/em><\/strong>\u00a0cie\u013eovej stanice (bez odde\u013eova\u010da).<\/span><\/p>\n

R\u00e1mec sa odosiela ako\u00a0<\/span>UDP<\/span><\/strong>\u00a0a odpor\u00fa\u010da sa pou\u017ei\u0165 port 9 discard alebo 7 echo, ale v\u00e4\u010d\u0161inou sa port nekontroluje, tak\u017ee sa m\u00f4\u017ee pou\u017ei\u0165 \u013eubovo\u013en\u00fd od 0 do 65535. Zdrojov\u00fd port je dynamick\u00fd.<\/span><\/p>\n

WOL v lok\u00e1lnom subnete<\/span><\/h3>\n

Pomocou Broadcast<\/span><\/h4>\n

Ak s\u00fa obe stanice (vysielaj\u00faca i buden\u00e1) vo <\/span>rovnakom subnete<\/span><\/em><\/strong>, tak je situ\u00e1cia jednoduch\u00e1 a bezprobl\u00e9mov\u00e1. Be\u017ene to funguje tak, \u017ee sa\u00a0<\/span>Magic Packet<\/span><\/em><\/strong>\u00a0po\u0161le ako\u00a0<\/span>broadcast<\/span><\/em><\/strong>.\u00a0Teda hodnoty v r\u00e1mci s\u00fa na L2 (druh\u00e1 vrstva pod\u013ea OSI modelu)\u00a0<\/span>zdrojov\u00e1 MAC = vysielaj\u00faca stanica<\/code>,\u00a0<\/span>cie\u013eov\u00e1 MAC = FF:FF:FF:FF:FF:FF<\/code>.\u00a0L3\u00a0<\/span>zdrojov\u00e1 IP adresa = vysielaj\u00faca stanica<\/code>,\u00a0<\/span>cie\u013eov\u00e1 IP = 255.255.255.255<\/code>.<\/span><\/p>\n

\"\"<\/p>\n

Pozn .:<\/em><\/strong> Z toho je vidie\u0165, \u017ee pre pou\u017eitie potrebujeme pozna\u0165 iba MAC adresu preb\u00fadzanej stanice.<\/span><\/p>\n

Pozn .:<\/em><\/strong>\u00a0Ak by sme Magic Packet v r\u00e1mci rovnak\u00e9ho subnetu chceli posla\u0165 ako unicast, tak d\u00f4jde k probl\u00e9mu.\u00a0Ke\u010f fyzick\u00e1 vrstva sie\u0165ov\u00e9ho rozhrania vytv\u00e1ra r\u00e1mec a nepozn\u00e1 MAC adresu pre zadan\u00fa IP adresu (z lok\u00e1lnej ARP tabu\u013eky), tak odo\u0161le ARP dotaz (broadcast), na ktor\u00fd nedostane odpove\u010f, tak\u017ee r\u00e1mec nikdy nevytvor\u00ed.\u00a0My s\u00edce MAC adresu pozn\u00e1me (a navy\u0161e nie je d\u00f4le\u017eit\u00e1), ale to by sme museli vytvori\u0165 r\u00e1mec sami na ni\u017e\u0161ej vrstve.<\/span><\/p>\n

WOL do vzdialen\u00e9ho subnetu (cez internet)<\/span><\/h3>\n

Zlo\u017eitej\u0161ia situ\u00e1cia nastane, ak buden\u00e1 stanica nie je v rovnakom subnete, to znamen\u00e1, \u017ee v ceste sa nach\u00e1dza jeden alebo viacero <\/span>routerov<\/span><\/em><\/strong>.\u00a0V\u0161etko plynie z princ\u00edpu komunik\u00e1cie v sieti (alebo funkcie akt\u00edvnych sie\u0165ov\u00fdch prvkov)<\/span>.<\/span><\/p>\n

Prv\u00e1 vec je, \u017ee\u00a0<\/span>router<\/span><\/em><\/strong>\u00a0odde\u013euje\u00a0<\/span>broadcastov\u00e9 dom\u00e9ny<\/span><\/em><\/strong>, jednoduch\u0161ie povedan\u00e9, Broadcast sa cez router ne\u0161\u00edri (\u0161tandardne, d\u00e1 sa to ob\u00eds\u0165 \u0161peci\u00e1lnou konfigur\u00e1ciou routera). Aplik\u00e1cie, ktor\u00e9 sa daj\u00fa z\u00edska\u0165 na internete, v\u00e4\u010d\u0161inou pon\u00fakaj\u00fa aj mo\u017enos\u0165 zadania <\/span>IP adresy<\/span><\/em><\/strong> budenej stanice (a bohu\u017eia\u013e v\u00e4\u010d\u0161inou bez popisu \u010do ako zad\u00e1va\u0165). A od toho sa na internete vedie rad diskusi\u00ed.\u00a0Ve\u010f predsa vypnut\u00e1 stanica nem\u00e1 IP adresu, sie\u0165ov\u00e1 karta m\u00e1 iba svoju hardv\u00e9rov\u00fa adresu, teda MAC adresu.\u00a0Ale pou\u017eitie tejto\u00a0<\/span>IP adresy<\/span><\/em><\/strong> nesl\u00fa\u017ei na identifik\u00e1ciu stanice, ale k\u00a0\u00a0<\/span>identifik\u00e1cii subnetu<\/span><\/em><\/strong>.<\/span><\/p>\n

Pozn .:<\/em><\/strong>\u00a0Sie\u0165ov\u00e1 karta v\u00a0\u00a0Magic Packet Mode<\/em><\/strong>\u00a0sa v\u00e4\u010d\u0161inou nepozer\u00e1 na L2, L3 ani L4, ale iba do d\u00e1tov\u00e9ho obsahu r\u00e1mca.<\/span><\/p>\n

Pomocou unicast<\/span><\/h4>\n

Ak je cie\u013e v\u00a0<\/span>inom subnete<\/span><\/em><\/strong>, tak m\u00f4\u017eeme pou\u017ei\u0165\u00a0<\/span>unicast<\/span><\/em><\/strong>, ale to funguje len chv\u00ed\u013eu (mo\u017en\u00e9 \u010dasy s\u00fa uveden\u00e9 \u010falej) po vypnut\u00ed po\u010d\u00edta\u010da.\u00a0Pri odosielan\u00ed paketu na\u0161a stanica zist\u00ed, \u017ee cie\u013e je v inom subnete, tak\u017ee spr\u00e1vu po\u0161le na <\/span>br\u00e1nu<\/span><\/em><\/strong> (gateway alebo pod\u013ea svojej routovacej tabu\u013eky, do r\u00e1mca sa pou\u017eije MAC adresa br\u00e1ny a IP adresa cie\u013ea, to rie\u0161i fyzick\u00e1 vrstva sie\u0165ov\u00e9ho rozhrania). Ak\u00a0<\/span>router<\/span><\/strong>\u00a0m\u00e1 v\u00a0<\/span>ARP tabu\u013eke<\/span><\/em><\/strong>\u00a0ulo\u017een\u00fa dan\u00fa cie\u013eov\u00fa IP adresu, tak pou\u017eije spr\u00e1vnu MAC adresu a odo\u0161le r\u00e1mec.\u00a0Ak dostane r\u00e1mec\u00a0<\/span>switch<\/span><\/strong>\u00a0a v\u00a0\u00a0<\/span>CAM tabu\u013eke <\/span><\/em><\/strong>(Tabu\u013eka MAC adries a portov) nem\u00e1 z\u00e1znam, tak po\u0161le spr\u00e1vu na v\u0161etky porty mimo prich\u00e1dzaj\u00faceho.\u00a0Ak e\u0161te z\u00e1znam m\u00e1, tak po\u0161le priamo na dan\u00fd port.<\/span><\/p>\n

Probl\u00e9m ale nastane, ke\u010f\u00a0<\/span>router<\/span><\/em><\/strong>\u00a0nem\u00e1 z\u00e1znam v ARP tabu\u013eke.\u00a0Vtedy po\u0161le\u00a0<\/span>broadcast<\/span><\/em><\/strong>, kde sa p\u00fdta, kto m\u00e1 dan\u00fa IP adresu, ale preto\u017ee nedostane odpove\u010f (od vypnutej stanice), tak <\/span>paket zahod\u00ed<\/span><\/em><\/strong>.<\/span><\/p>\n

Pozn .:<\/em><\/strong> V tomto pr\u00edpade teda potrebujeme MAC adresu cie\u013eovej stanice a jej posledn\u00fa IP adresu. Teoreticky by sme mohli pou\u017ei\u0165 aj in\u00fa IP adresu z dan\u00e9ho subnetu, ale ide o to, aby ju router mal vo svojej ARP tabu\u013eke (je n\u00e1m jedno, \u017ee jej na L2 prirad\u00ed in\u00fa MAC adresu) a naopak switch, aby t\u00fato priraden\u00fa MAC adresu nemal v CAM tabu\u013eke, preto\u017ee by r\u00e1mec odoslal len na in\u00fd port. Ak by sme za routerom mali hub, tak by sme mohli pou\u017ei\u0165 IP adresu \u013eubovo\u013enej be\u017eiacej stanice v danom subnetu a v\u017edy by n\u00e1m to fungovalo.<\/span><\/p>\n

Pomocou smerovan\u00e9ho Broadcast<\/span><\/h4>\n

Aby sme teda dostali paket do cie\u013eov\u00e9ho subnetu, m\u00f4\u017eeme pou\u017ei\u0165\u00a0<\/span>smerovan\u00fd broadcast na subnet<\/span><\/em><\/strong>\u00a0(Subnet Directed Broadcast, napr. 10.0.0.255), ktor\u00fd pou\u017e\u00edva\u00a0<\/span>boradcastov\u00fa adresu dan\u00e9ho subnetu<\/span><\/em><\/strong>.\u00a0Ten by mal cestova\u0165 cez routre a\u017e na ten, ktor\u00fd m\u00e1 dan\u00fd subnet ako priamo pripojen\u00fd.\u00a0Tento\u00a0<\/span>router<\/span><\/em><\/strong>\u00a0uprav\u00ed r\u00e1mec na be\u017en\u00fd\u00a0<\/span>broadcast<\/span><\/em><\/strong>\u00a0a odo\u0161le ho na zodpovedaj\u00face rozhranie.<\/span><\/p>\n

Pozn .:<\/em><\/strong>\u00a0V tomto pr\u00edpade teda potrebujeme MAC adresu cie\u013eovej stanice a broadcastov\u00e9 adresu subnetu, v ktorom sa nach\u00e1dza.<\/span><\/p>\n

Ke\u010f\u017ee v\u0161ak t\u00e1to technika bola pou\u017e\u00edvan\u00e1 k \u00fatokom, tak b\u00fdva na routeroch alebo i firewalloch v\u00e4\u010d\u0161inou\u00a0<\/span>zak\u00e1zan\u00e1<\/span><\/em><\/strong>.\u00a0To sa t\u00fdka routera, ktor\u00fd by mal r\u00e1mec previes\u0165 na broadcast, cez ostatn\u00e9 by mal r\u00e1mec prejs\u0165 norm\u00e1lne.<\/span><\/p>\n

Pozn .:<\/em><\/strong> Najbe\u017enej\u0161\u00ed je Smurf Attack<\/strong>, ktor\u00fd m\u00e1 zariadi\u0165\u00a0Denial of Services<\/em><\/strong>\u00a0(DoS).\u00a0\u00dato\u010dn\u00edk odosiela mno\u017estvo paketov\u00a0\u00a0ICMP echo reply<\/code>s podvrhnutou zdrojovou adresou ako DIRECTED broadcast, v\u0161etky stanice v subnetu odpovedaj\u00faecho reply<\/code>a stanica, ktorej adresa je t\u00e1 podvrhnut\u00e1, je zahlten\u00e1.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

Wake on LAN\u00a0(WOL) funguje na\u00a0Ethernete a je nez\u00e1visl\u00fd na pou\u017e\u00edvanom protokole (TCP\/IP, IPX \u010di in\u00fd). Ako n\u00e1zov napoved\u00e1, tak budenie funguje v r\u00e1mci lok\u00e1lnej siete.\u00a0LAN\u00a0predt\u00fdm…<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":13,"menu_order":1,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"_links":{"self":[{"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/pages\/707"}],"collection":[{"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/comments?post=707"}],"version-history":[{"count":1,"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/pages\/707\/revisions"}],"predecessor-version":[{"id":709,"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/pages\/707\/revisions\/709"}],"up":[{"embeddable":true,"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/pages\/13"}],"wp:attachment":[{"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/media?parent=707"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}