{"id":73867,"date":"2020-03-12T14:42:29","date_gmt":"2020-03-12T11:42:29","guid":{"rendered":"https:\/\/prohoster.info\/blog\/administrirovanie\/seti-dlya-nachinayushhego-it-speczialista-obyazatelnaya-baza"},"modified":"2020-03-12T14:42:29","modified_gmt":"2020-03-12T11:42:29","slug":"seti-dlya-nachinayushhego-it-speczialista-obyazatelnaya-baza","status":"publish","type":"post","link":"https:\/\/prohoster.info\/ro\/blog\/administrirovanie\/seti-dlya-nachinayushhego-it-speczialista-obyazatelnaya-baza","title":{"rendered":"Re\u021bele pentru \u00eencep\u0103torii \u00een IT. O baz\u0103 obligatorie.","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"<p>Aproximativ 80% dintre noi, cei care termin\u0103m universitatea cu o specializare IT, nu devin programatori. Mul\u021bi se angajeaz\u0103 \u00een suport tehnic, ca administratori de sistem, tehnicieni \u00een repararea echipamentelor computerizate, consultan\u021bi-v\u00e2nz\u0103tori de tehnologie digital\u0103, manageri \u00een domeniul IT \u0219i a\u0219a mai departe.<\/p>\n<p><\/p>\n<p>Aceast\u0103 articol este exact pentru acele 80% care tocmai au terminat universitatea cu o specializare IT \u0219i au \u00eenceput deja s\u0103 monitorizeze ofertele de munc\u0103, de exemplu, pentru pozi\u021bii de administrator de sistem sau asistent al acestuia, inginer de teren \u00eentr-o firm\u0103 de outsourcing sau \u00een suport tehnic de prim\u0103\/ a doua linie.<\/p>\n<p><\/p>\n<p>De asemenea, este destinat studiului individual sau instruirii noilor angaja\u021bi.<\/p>\n<p><\/p>\n<p>\u00cen timpul carierei mele \u00een domeniul IT, m-am confruntat cu problema c\u0103 universit\u0103\u021bile nu ofer\u0103 baza fundamental\u0103 referitoare la re\u021bele. Am realizat acest lucru mai \u00eent\u00e2i pe pielea mea, c\u00e2nd, dup\u0103 finalizarea universit\u0103\u021bii, am mers la interviuri \u00een 2016 \u0219i nu am putut r\u0103spunde la \u00eentreb\u0103ri simple (a\u0219a mi se par acum). Atunci mi s-a p\u0103rut c\u0103 am neglijat studiul la universitate. Dar, de fapt, problema este \u00een programul educa\u021bional. Acum, m\u0103 confrunt din nou cu aceast\u0103 lacun\u0103 de cuno\u0219tin\u021be atunci c\u00e2nd instruiesc noi angaja\u021bi.<\/p>\n<p><\/p>\n<p>\u0218i ce a fost atunci? A trebuit s\u0103 studiez numeroase articole pe internet, \u00eenainte s\u0103 \u00een\u021beleg conceptele de baz\u0103. Acum, c\u00e2nd le dau tinerilor speciali\u0219ti subiecte de studiu, ei g\u0103sesc cu dificultate \u0219i absorb informa\u021biile necesare. Acest lucru se \u00eent\u00e2mpl\u0103 pentru c\u0103 pe internet exist\u0103 o cantitate imens\u0103 de articole, toate fiind dispersate pe teme, sau scrise \u00eentr-un limbaj prea complicat. \u00cen plus, majoritatea informa\u021biilor din \u00eenceputul articolelor con\u021bin \u00een principal defini\u021bii \u0219tiin\u021bifice \u0219i apoi trec direct la tehnologii complexe de utilizare. Rezultatul este c\u0103 pentru \u00eencep\u0103tori devine foarte confuz.<\/p>\n<p><\/p>\n<p>De aceea, am decis s\u0103 adun temele principale \u00eentr-un singur articol \u0219i s\u0103 le explic pe \u00een\u021belesul tuturor, c\u00e2t mai simplu. <\/p>\n<p><noindex><a rel=\"nofollow\" name=\"habracut\"><\/a><\/noindex><\/p>\n<p>Aten\u021bie, \u00een acest articol nu va fi nicio informa\u021bie detaliat\u0103, doar cele mai de baz\u0103 \u0219i esen\u021biale concepte.<\/p>\n<p><\/p>\n<p><strong>Temele abordate sunt:<\/strong><\/p>\n<p><\/p>\n<ol>\n<li>Re\u021bele globale \u0219i locale<\/li>\n<li>Adres\u0103 IP alb\u0103 \u0219i gri<\/li>\n<li>NAT<\/li>\n<li>Server DHCP \u0219i subre\u021bele<\/li>\n<li>Dispozitive de rutare a re\u021belei (router, switch, hub)<\/li>\n<li>Comenzile principale pentru analiza re\u021belei<\/li>\n<li>Protocoalele de transport UDP \u0219i TCP<\/li>\n<\/ol>\n<p><\/p>\n<h3 id=\"1--globalnye-i-lokalnye-seti\">1. Re\u021bele globale \u0219i locale<\/h3>\n<p><\/p>\n<p>\u00centreaga re\u021bea de internet este \u00eemp\u0103r\u021bit\u0103 \u00een <strong>global\u0103 (WAN)<\/strong> \u0219i <strong>local\u0103 (LAN)<\/strong>.<\/p>\n<p><\/p>\n<p>Toate dispozitivele utilizatorului din cadrul unei apartamente, birou sau chiar cl\u0103diri (calculatoare, smartphone-uri, imprimante\/ multifunc\u021bionale, televizoare etc.) se conecteaz\u0103 la un router, care le une\u0219te \u00eentr-o <strong>re\u021bea local\u0103<\/strong>. <\/p>\n<p><\/p>\n<p>Participan\u021bii unei re\u021bele locale pot schimba date \u00eentre dispozitivele lor f\u0103r\u0103 a se conecta la furnizorul de internet. \u00cens\u0103 pentru a accesa re\u021beaua (de exemplu, pentru a c\u0103uta pe Yandex sau Google, a accesa VK, Instagram, YouTube sau AmoCRM) este necesar accesul la <strong>re\u021beaua global\u0103<\/strong>. <\/p>\n<p><\/p>\n<p>Ie\u0219irea \u00een <strong>re\u021beaua global\u0103<\/strong> o asigur\u0103 furnizorul de internet, pentru care pl\u0103tim o tax\u0103 de abonament. Furnizorul stabile\u0219te pe routerele sale nivelul de vitez\u0103 pentru fiecare conexiune conform tarifelor. Furnizorul ne furnizeaz\u0103 un cablu twisted pair sau fibr\u0103 optic\u0103 p\u00e2n\u0103 la routerul nostru (re\u021beaua noastr\u0103 local\u0103) \u0219i dup\u0103 aceea orice dispozitiv din <strong>re\u021beaua noastr\u0103 local\u0103<\/strong> poate accesa <strong>re\u021beaua global\u0103<\/strong>.<\/p>\n<p><\/p>\n<p>Pentru o analogie, re\u021belele pot fi comparate cu drumurile.<br \/>\nDe exemplu, drumurile din ora\u0219ul vostru N sunt <strong>re\u021beaua local\u0103<\/strong>. Aceste drumuri v\u0103 conecteaz\u0103 cu magazinele, institu\u021biile, parcurile \u0219i alte locuri din ora\u0219ul vostru.<br \/>\nPentru a ajunge \u00een alt ora\u0219 N, este necesar s\u0103 ie\u0219i\u021bi pe \u0219oseaua federal\u0103 \u0219i s\u0103 parcurge\u021bi o anumit\u0103 distan\u021b\u0103. Adic\u0103 s\u0103 ie\u0219i\u021bi \u00een <strong>re\u021beaua global\u0103<\/strong>.<\/p>\n<p><\/p>\n<p>Pentru o reprezentare mai clar\u0103 a ceea ce este <strong>re\u021beaua global\u0103 \u0219i local\u0103<\/strong> am desenat o schem\u0103.<\/p>\n<p><\/p>\n<p><img decoding=\"async\" alt=\"Re\u021bele pentru \u00eencep\u0103torii \u00een IT. O baz\u0103 obligatorie.\" src=\"\/wp-content\/uploads\/2020\/03\/76cb6f31b3282803e3b42d302fa393a2.jpg\" style=\"display:block;margin: 0 auto;\" \/><\/p>\n<p><\/p>\n<h3 id=\"2--belye-i-serye-ip-adresa\">2. Adrese IP albe \u0219i gri<\/h3>\n<p><\/p>\n<p>Fiecare dispozitiv din re\u021bea are propria <strong>adres\u0103 IP unic\u0103<\/strong>. Aceasta este necesar\u0103 pentru ca dispozitivele din re\u021bea s\u0103 \u00een\u021beleag\u0103 unde trebuie s\u0103 direc\u021bioneze cererea \u0219i r\u0103spunsul.<br \/>\nEste la fel ca \u0219i casele sau apartamentele noastre, care au o adres\u0103 precis\u0103 (cod po\u0219tal, ora\u0219, strad\u0103, nr. cl\u0103dirii, nr. apartamentului).<\/p>\n<p><\/p>\n<p>\u00cen cadrul re\u021belei voastre locale (apartament, birou sau cl\u0103dire) exist\u0103 o gam\u0103 proprie de adrese unice. Cred c\u0103 mul\u021bi a\u021bi observat c\u0103 adresa IP a unui computer, de exemplu, \u00eencepe cu cifrele 192.168.X.X <\/p>\n<p><\/p>\n<p>A\u0219adar, aceasta este adresa local\u0103 a dispozitivului vostru.<\/p>\n<p><\/p>\n<p>Exist\u0103 <strong>intervalele de adrese locale permise<\/strong>:<\/p>\n<p><\/p>\n<p><img decoding=\"async\" alt=\"Re\u021bele pentru \u00eencep\u0103torii \u00een IT. O baz\u0103 obligatorie.\" src=\"\/wp-content\/uploads\/2020\/03\/e578389cd29c2c335c7af3c68833e0db.jpg\" style=\"display:block;margin: 0 auto;\" \/><\/p>\n<p><\/p>\n<p>Cred c\u0103 din tabela prezentat\u0103 devine evident de ce cel mai r\u0103sp\u00e2ndit interval este 192.168.X.X<\/p>\n<p><\/p>\n<p>Pentru a afla, de exemplu, adresa IP a computerului vostru (pe baza sistemului de operare Windows), introduce\u021bi \u00een terminal comanda <strong>ipconfig<\/strong><\/p>\n<p><\/p>\n<p><img decoding=\"async\" alt=\"Re\u021bele pentru \u00eencep\u0103torii \u00een IT. O baz\u0103 obligatorie.\" src=\"\/wp-content\/uploads\/2020\/03\/a7f278d28be2ef8d71a6a9da48498473.jpg\" style=\"display:block;margin: 0 auto;\" \/><\/p>\n<p><\/p>\n<p>Dup\u0103 cum pute\u021bi vedea, adresa IP a computerului meu \u00een re\u021beaua local\u0103 de acas\u0103 <strong>192.168.88.251<br \/>\n<\/strong><br \/>\nPentru a ie\u0219i \u00een re\u021belele globale, adresa dumneavoastr\u0103 <strong>IP local<\/strong> este \u00eenlocuit\u0103 de router cu <strong>o adres\u0103 IP global\u0103<\/strong>, care v-a fost furnizat\u0103 de furnizor. Adresele IP globale nu se \u00eencadreaz\u0103 \u00een intervalele din tabelul de mai sus.<\/p>\n<p><\/p>\n<p>So, it <strong>Adresele IP locale sunt adrese IP gri, iar cele globale sunt albe.<\/strong>.<\/p>\n<p><\/p>\n<p>Pentru o mai bun\u0103 \u00een\u021belegere, analiza\u021bi schema de mai jos. Pe aceasta am etichetat fiecare dispozitiv cu adresa sa IP.<\/p>\n<p><\/p>\n<p><img decoding=\"async\" alt=\"Re\u021bele pentru \u00eencep\u0103torii \u00een IT. O baz\u0103 obligatorie.\" src=\"\/wp-content\/uploads\/2020\/03\/4165e6c62082a77f5f87c9bcd11acd18.jpg\" style=\"display:block;margin: 0 auto;\" \/><\/p>\n<p><\/p>\n<p>\u00cen schem\u0103 se poate observa c\u0103 furnizorul ne elibereaz\u0103 \u00een re\u021belele globale (pe internet) din <strong>adresa IP alb\u0103 91.132.25.108<\/strong><\/p>\n<p><\/p>\n<p>Pentru routerul nostru, furnizorul a alocat o adres\u0103 IP gri <strong>172.17.135.11<\/strong><br \/>\n\u0218i \u00een re\u021beaua noastr\u0103 local\u0103, toate dispozitivele de asemenea au <strong>adrese IP gri 192.168.X.X<\/strong><\/p>\n<p><\/p>\n<p>Pute\u021bi afla sub ce adres\u0103 IP ie\u0219i\u021bi \u00een re\u021beaua global\u0103 acces\u00e2nd site-ul <noindex><a rel=\"nofollow\" href=\"https:\/\/2ip.ru\/\">2ip.ro<\/a><\/noindex><\/p>\n<p><\/p>\n<p><img decoding=\"async\" alt=\"Re\u021bele pentru \u00eencep\u0103torii \u00een IT. O baz\u0103 obligatorie.\" src=\"\/wp-content\/uploads\/2020\/03\/067c5299fe169bf5a19b704800cb241e.jpg\" style=\"display:block;margin: 0 auto;\" \/><\/p>\n<p><\/p>\n<p>Dar din toate acestea merit\u0103 s\u0103 re\u021binem <strong>un factor foarte important!<\/strong><br \/>\n\u00cen prezent, problema lipsei adreselor IP albe a devenit acut\u0103, deoarece num\u0103rul dispozitivelor de re\u021bea a dep\u0103\u0219it demult num\u0103rul adreselor IP disponibile. Din acest motiv, furnizorii de internet ofer\u0103 utilizatorilor <strong>adrese IP gri<\/strong> (\u00een cadrul re\u021belei locale a furnizorului, de exemplu, \u00een cadrul mai multor blocuri de apartamente) \u0219i ne elibereaz\u0103 \u00een re\u021beaua global\u0103 sub o singur\u0103 <strong>adres\u0103 IP alb\u0103.<\/strong>.<\/p>\n<p><\/p>\n<p>Pentru a verifica dac\u0103 furnizorul v\u0103 ofer\u0103 o adres\u0103 IP gri sau alb\u0103, pute\u021bi accesa routerul \u0219i verifica ce adres\u0103 IP prime\u0219te routerul de la furnizor.<\/p>\n<p><\/p>\n<p>De asemenea, pute\u021bi accesa, de exemplu, site-ul <noindex><a rel=\"nofollow\" href=\"https:\/\/www.mobilon.ru\/\">mobilon.ro<\/a><\/noindex> iar \u00een partea de jos (\u00een subsolul site-ului) ve\u021bi vedea adresa IP a routerului dumneavoastr\u0103.<\/p>\n<p><\/p>\n<p>De exemplu, eu am intrat prin internetul de acas\u0103:<\/p>\n<p><\/p>\n<p><img decoding=\"async\" alt=\"Re\u021bele pentru \u00eencep\u0103torii \u00een IT. O baz\u0103 obligatorie.\" src=\"\/wp-content\/uploads\/2020\/03\/b53e87c2a37bf540d9b4c742949daeff.jpg\" style=\"display:block;margin: 0 auto;\" \/><\/p>\n<p><\/p>\n<p>Dup\u0103 cum vede\u021bi, de fapt am <strong>o adres\u0103 IP gri 172.17.132.2<\/strong> (consulta\u021bi intervalul adreselor locale). Pentru a ob\u021bine o adres\u0103 IP alb\u0103, furnizorii ofer\u0103 de obicei un serviciu suplimentar contra unei taxe.<\/p>\n<p><\/p>\n<p>\u00cen realitate, pentru internetul de acas\u0103, aceasta nu este o problem\u0103 critic\u0103. Totu\u0219i, <strong>pentru birourile companiilor, se recomand\u0103 achizi\u021bionarea de la furnizor a unei adrese IP albe<\/strong>, deoarece utilizarea unei adrese IP gri implic\u0103 probleme cu func\u021bionarea telefoniei IP, iar de asemenea nu va fi posibil\u0103 configurarea conexiunii la distan\u021b\u0103 prin VPN. Aceasta \u00eenseamn\u0103 c\u0103 o adres\u0103 IP gri nu v\u0103 va permite s\u0103 publica\u021bi pe internet serverul configurat \u0219i nu va permite configurarea unei conexiuni la distan\u021b\u0103 la server dintr-o alt\u0103 re\u021bea.<\/p>\n<p><\/p>\n<h3 id=\"3-nat\">3. NAT<\/h3>\n<p><\/p>\n<p>\u00cen sec\u021biunea anterioar\u0103 am men\u021bionat c\u0103 \"<em>\u00cen prezent, problema lipsei adreselor IP publice s-a \u00eenr\u0103ut\u0103\u021bit.<\/em>Astfel, schema comun\u0103 de conectare la furnizorii de internet este acum conectarea multor clien\u021bi cu adrese IP private, iar \u00een internetul global se emite un singur IP public.<\/p>\n<p><\/p>\n<p>Dar nu a fost \u00eentotdeauna a\u0219a; ini\u021bial, tuturor le-au fost atribuite adrese IP publice, iar \u00een cur\u00e2nd, pentru a evita problema deficitului de adrese IP publice, a fost inventat <strong>NAT (Network Address Translation) \u2014 mecanismul de conversie a adreselor IP.<\/strong>.<\/p>\n<p><\/p>\n<p><strong>NAT<\/strong> Func\u021bioneaz\u0103 pe toate routerele \u0219i ne permite s\u0103 ie\u0219im din re\u021beaua local\u0103 \u00een global\u0103.<\/p>\n<p><\/p>\n<p>Pentru a \u00een\u021belege mai bine, s\u0103 analiz\u0103m dou\u0103 exemple:<\/p>\n<p><\/p>\n<p><strong>1. Primul caz:<\/strong> ai achizi\u021bionat <strong>adresa IP public\u0103 91.105.8.10<\/strong> iar \u00een re\u021beaua local\u0103 sunt conectate mai multe dispozitive.<\/p>\n<p><\/p>\n<p><img decoding=\"async\" alt=\"Re\u021bele pentru \u00eencep\u0103torii \u00een IT. O baz\u0103 obligatorie.\" src=\"\/wp-content\/uploads\/2020\/03\/d42fc6db3e7aea73c6241f89d437fb33.jpg\" style=\"display:block;margin: 0 auto;\" \/><\/p>\n<p><\/p>\n<p>Fiecare dispozitiv local are propria adres\u0103 IP privat\u0103. \u00cens\u0103 accesul la internet este posibil numai cu adresa IP public\u0103.<\/p>\n<p><\/p>\n<p>Prin urmare, c\u00e2nd, de exemplu, PC1 cu adresa IP 192.168.1.3 a decis s\u0103 acceseze motorul de c\u0103utare Yandex, routerul, emite solicitarea PC1 \u00een re\u021beaua global\u0103, activeaz\u0103 mecanismul <strong>NAT<\/strong>, care <strong>care transform\u0103 adresa IP a PC1 \u00een adresa IP public\u0103 global\u0103 91.105.8.10.<\/strong><\/p>\n<p><\/p>\n<p>De asemenea, \u00een direc\u021bia invers\u0103, c\u00e2nd routerul prime\u0219te un r\u0103spuns de la serverul Yandex, folose\u0219te mecanismul <strong>NAT<\/strong> pentru a direc\u021biona acest r\u0103spuns la adresa IP 192.168.1.3, la care este conectat PC1.<\/p>\n<p><\/p>\n<p><strong>2. Al doilea caz:<\/strong> ai \u0219i \u00een re\u021beaua local\u0103 conectate mai multe dispozitive, dar nu ai achizi\u021bionat o adres\u0103 IP public\u0103 de la furnizorul de internet.<\/p>\n<p><\/p>\n<p><img decoding=\"async\" alt=\"Re\u021bele pentru \u00eencep\u0103torii \u00een IT. O baz\u0103 obligatorie.\" src=\"\/wp-content\/uploads\/2020\/03\/92689ebbbc428f49a5b2357a6c5bef0b.jpg\" style=\"display:block;margin: 0 auto;\" \/><\/p>\n<p><\/p>\n<p>\u00cen acest caz, adresa local\u0103 <strong>PC1(192.168.1.3)<\/strong> este mai \u00eent\u00e2i transformat\u0103 <strong>NAT<\/strong>routerului dumneavoastr\u0103 \u0219i devine <strong>adres\u0103 IP privat\u0103 172.17.115.3<\/strong>, pe care \u021bi-a alocat furnizorul de internet, iar apoi adresa ta IP privat\u0103 este transformat\u0103 <strong>NAT<\/strong>de c\u0103tre routerul furnizorului \u00een <strong>adresa IP public\u0103 91.105.108.10<\/strong>, \u0219i abia dup\u0103 aceea se realizeaz\u0103 accesul la internet (re\u021beaua global\u0103).<\/p>\n<p><\/p>\n<p>Adic\u0103, \u00een acest caz, se dovede\u0219te c\u0103 dispozitivele tale se afl\u0103 \u00een spatele unei dubl\u0103ri. <strong>NAT<\/strong>Aceast\u0103 schem\u0103 ofer\u0103 o securitate mai mare pentru dispozitivele tale, dar implic\u0103 \u0219i o serie de dezavantaje mari. De exemplu, \u00eenregistrarea SIP instabil\u0103 a echipamentului VoIP sau auz unidirec\u021bional \u00een apelurile prin telefonie IP.<\/p>\n<p><\/p>\n<p>Voi scrie un articol separat despre modul de func\u021bionare a mecanismului<\/p>\n<p><\/p>\n<p>, despre avantajele \u0219i dezavantajele sale, despre alocarea porturilor, despre socket-uri \u0219i despre tipurile <strong>NAT<\/strong>. <strong>NAT<\/strong> 4. DHCP \u2014 server \u0219i subre\u021bele.<\/p>\n<p><\/p>\n<h3 id=\"4--dhcp---server-i-podseti\">4. DHCP \u2013 server \u0219i subre\u021bele<\/h3>\n<p><\/p>\n<p>Pentru a conecta un dispozitiv, cum ar fi un computer la internet, de obicei, conecta\u021bi cablul (cablul twisted pair) la computer \u0219i apoi \u00eentr-un port liber de pe router, dup\u0103 care computerul prime\u0219te automat o adres\u0103 IP \u0219i apare accesul la internet. <\/p>\n<p><\/p>\n<p>Acelasi lucru este valabil \u0219i pentru Wi-Fi, de exemplu, de pe un smartphone sau laptop, v\u0103 conecta\u021bi la re\u021beaua dorit\u0103, introduce\u021bi parola, dispozitivul prime\u0219te o adres\u0103 IP \u0219i ave\u021bi internet.<\/p>\n<p><\/p>\n<p>Un <strong>ce permite dispozitivului s\u0103 ob\u021bin\u0103 automat o adres\u0103 IP local\u0103?<\/strong><br \/>\nAceast\u0103 func\u021bie este \u00eendeplinit\u0103 de <strong>Server DHCP<\/strong>.<\/p>\n<p><\/p>\n<p>Fiecare router este echipat cu <strong>un server DHCP<\/strong>. Adresele IP ob\u021binute automat sunt <strong>adrese IP dinamice<\/strong>.<\/p>\n<p><\/p>\n<p>De ce sunt dinamice?<\/p>\n<p><\/p>\n<p>Pentru c\u0103, la fiecare nou\u0103 conectare sau la repornirea router-ului, <strong>Server DHCP<\/strong> se reinregistreaz\u0103 \u0219i poate atribui dispozitivelor adrese IP diferite.<\/p>\n<p><\/p>\n<p>Adic\u0103, de exemplu, acum computerul dumneavoastr\u0103 are adresa IP <strong>192.168.1.10<\/strong>, dup\u0103 repornirea router-ului, adresa IP a computerului poate deveni <strong>192.168.1.35<\/strong><\/p>\n<p><\/p>\n<p>Pentru a p\u0103stra aceea\u0219i adres\u0103 IP, o pute\u021bi seta <strong>static<\/strong>. Acest lucru se poate face fie pe computer \u00een set\u0103rile re\u021belei, fie pe routerul \u00een sine.<\/p>\n<p><\/p>\n<p>De asemenea, <strong>Server DHCP<\/strong> pe router pute\u021bi dezactiva complet \u0219i seta adresele IP manual.<\/p>\n<p><\/p>\n<p>Pute\u021bi configura mai multe <strong>servere DHCP<\/strong> pe un singur router. Atunci re\u021beaua local\u0103 se va \u00eemp\u0103r\u021bi \u00een <strong>subre\u021bele<\/strong>. <\/p>\n<p><\/p>\n<p>De exemplu, computerele vor fi conectate la subre\u021beaua zero \u00een intervalul 192.168.0.2-192.168.0.255, imprimantele la prima subre\u021bea \u00een intervalul 192.168.1.2-192.168.1.255, iar Wi-Fi-ul va fi distribuit pe a cincea subre\u021bea cu intervalul 192.168.5.2-192.168.5.255 (vezi schema de mai jos).<\/p>\n<p><\/p>\n<p><img decoding=\"async\" alt=\"Re\u021bele pentru \u00eencep\u0103torii \u00een IT. O baz\u0103 obligatorie.\" src=\"\/wp-content\/uploads\/2020\/03\/7b2a90c3ce4c6132b75ba31544804b5d.jpg\" style=\"display:block;margin: 0 auto;\" \/><\/p>\n<p><\/p>\n<p>De obicei, delimitarea pe subre\u021bele nu este necesar\u0103. Aceasta se face atunci c\u00e2nd \u00eentr-o companie sunt multe dispozitive conectate la re\u021bea \u0219i \u00een cadrul configur\u0103rii securit\u0103\u021bii re\u021belei.<\/p>\n<p><\/p>\n<p>Dar o astfel de schem\u0103 se \u00eent\u00e2lne\u0219te destul de frecvent \u00een companii.<br \/>\nPrin urmare, este esen\u021bial s\u0103 cunoa\u0219te\u021bi un aspect foarte important.<\/p>\n<p><\/p>\n<p><strong>Aten\u021bie!<br \/>\nDac\u0103 ave\u021bi nevoie s\u0103 accesa\u021bi interfa\u021ba web de pe PC, de exemplu, a unei imprimante sau a unui telefon IP \u0219i PC-ul dumneavoastr\u0103 se afl\u0103 \u00eentr-o alt\u0103 subre\u021bea, nu ve\u021bi putea realiza conexiunea.<\/strong><\/p>\n<p><\/p>\n<p>Pentru a \u00een\u021belege, s\u0103 analiz\u0103m un exemplu:<\/p>\n<p><\/p>\n<p><img decoding=\"async\" alt=\"Re\u021bele pentru \u00eencep\u0103torii \u00een IT. O baz\u0103 obligatorie.\" src=\"\/wp-content\/uploads\/2020\/03\/ffc9cdcb4ffa51a5b0296d4dad97938f.jpg\" style=\"display:block;margin: 0 auto;\" \/><\/p>\n<p><\/p>\n<p>S\u0103 presupunem c\u0103 lucra\u021bi pe <strong>PC1<\/strong> cu adresa IP local\u0103 <strong>10.10.5.2<\/strong> \u0219i dori\u021bi s\u0103 accesa\u021bi interfa\u021ba web <strong>a telefonului IP<\/strong> cu adresa IP local\u0103 <strong>192.168.1.3<\/strong>, nu ve\u021bi putea s\u0103 v\u0103 conecta\u021bi. Deoarece dispozitivele se afl\u0103 \u00een subre\u021bele diferite. La telefonul IP, situat \u00een subre\u021beaua <strong>192.168.1.X<\/strong>, se poate conecta doar de pe <strong>PC3 (192.168.1.5)<\/strong>.<\/p>\n<p><\/p>\n<p>De asemenea, la <strong>MFP (172.17.17.12)<\/strong> ve\u021bi putea s\u0103 v\u0103 conecta\u021bi doar de pe <strong>PC4 (172.17.17.10)<\/strong>.<\/p>\n<p><\/p>\n<p>A\u0219adar, c\u00e2nd te conectezi la distan\u021b\u0103 la un utilizator pe PC pentru a accesa interfa\u021ba web a telefonului IP, asigur\u0103-te mai \u00eent\u00e2i c\u0103 verifici adresele IP locale, pentru a te asigura c\u0103 ambele dispozitive sunt conectate la aceea\u0219i subre\u021bea.<\/p>\n<p><\/p>\n<h3 id=\"5--ustroystva-marshrutizacii-seti-marshrutizator-kommutator-svitch-hab\">5. Dispozitive de rutare a re\u021belei (router, switch, hub)<\/h3>\n<p><\/p>\n<p>Cum ar fi ciudat, dar exist\u0103 un fapt c\u0103 \u00eencep\u0103torii \u00een IT (uneori chiar \u0219i administratorii de sistem activi) nu \u0219tiu sau confund\u0103 astfel de concepte precum <strong>router, switch, gateway de re\u021bea \u0219i hub<\/strong>.<\/p>\n<p><\/p>\n<p>Cred c\u0103 motivul acestei confuzii a ap\u0103rut din cauza prolifer\u0103rii sinonimelor \u0219i jargonului \u00een denumirile echipamentelor de re\u021bea, iar acest lucru induce \u00een eroare mul\u021bi ingineri \u00eencep\u0103tori.<\/p>\n<p><\/p>\n<p>S\u0103 analiz\u0103m.<\/p>\n<p><\/p>\n<p><strong>a) Router, router \u0219i gateway de re\u021bea<\/strong><\/p>\n<p><\/p>\n<p>Toat\u0103 lumea \u0219tie ce este <strong>routerul<\/strong>. Acesta este exact dispozitivul care distribuie internetul \u00een interior, conectat de la furnizorul de internet.<\/p>\n<p><\/p>\n<p>So, it <strong>routerul \u0219i gateway-ul de re\u021bea sunt acelea\u0219i cu routerul<\/strong>.<\/p>\n<p><\/p>\n<p>Acest echipament este principalul dispozitiv \u00eentr-o re\u021bea organizat\u0103. \u00cen mediul ingineresc, cea mai folosit\u0103 denumire este \u201c<strong>routerul<\/strong>\u201d.<\/p>\n<p><\/p>\n<p>Apropo, un router nu este doar un aparat, ci \u0219i unitatea central\u0103 a unui computer, dac\u0103 instalezi o alt\u0103 plac\u0103 de re\u021bea \u0219i instalezi, de exemplu, RouterOS Mikrotik. Apoi, po\u021bi gestiona re\u021beaua cu numeroase dispozitive printr-un switch.<\/p>\n<p><\/p>\n<p><img decoding=\"async\" alt=\"Re\u021bele pentru \u00eencep\u0103torii \u00een IT. O baz\u0103 obligatorie.\" src=\"\/wp-content\/uploads\/2020\/03\/52b2a8231ad7fe954e676a2136f6d151.jpg\" style=\"display:block;margin: 0 auto;\" \/><\/p>\n<p><\/p>\n<p><strong>b) Ce este un Switch \u0219i cu ce se deosebe\u0219te de un Comutator \u0219i un Hub<\/strong><\/p>\n<p><\/p>\n<p><strong>Switch-ul \u0219i Comutatorul<\/strong> sunt, de asemenea, <strong>sinonime<\/strong>. Iar acum <strong>hub-ul<\/strong> este un dispozitiv pu\u021bin diferit. Despre acesta \u00een punctul urm\u0103tor (v).<\/p>\n<p><\/p>\n<p><img decoding=\"async\" alt=\"Re\u021bele pentru \u00eencep\u0103torii \u00een IT. O baz\u0103 obligatorie.\" src=\"\/wp-content\/uploads\/2020\/03\/09ccfe25b21c76654c7adbff38681327.jpg\" style=\"display:block;margin: 0 auto;\" \/><\/p>\n<p><\/p>\n<p><strong>Comutatorul (switch)<\/strong> este folosit pentru ramificarea re\u021belei locale. Ca un splitter sau filtru de re\u021bea, la care ne conect\u0103m dispozitivele pentru a le alimenta electric dintr-o singur\u0103 priz\u0103.<\/p>\n<p><\/p>\n<p><img decoding=\"async\" alt=\"Re\u021bele pentru \u00eencep\u0103torii \u00een IT. O baz\u0103 obligatorie.\" src=\"\/wp-content\/uploads\/2020\/03\/744f857142a3c3f5b561ef42b9c91593.jpg\" style=\"display:block;margin: 0 auto;\" \/><\/p>\n<p><\/p>\n<p><strong>Comutatorul nu poate ruta re\u021beaua ca un router<\/strong>. Nu va oferi dispozitivului t\u0103u o adres\u0103 IP \u0219i, f\u0103r\u0103 ajutorul unui router, nu te va putea duce la internet.<\/p>\n<p><\/p>\n<p>Un router standard are de obicei 4-5 porturi pentru conectarea dispozitivelor. \u00cen consecin\u021b\u0103, dac\u0103 dispozitivele tale sunt conectate prin cabluri \u0219i sunt mai multe dec\u00e2t porturile de pe router, \u00ee\u021bi trebuie un switch. Po\u021bi conecta un switch de 24 de porturi la un port al routerului \u0219i po\u021bi organiza lini\u0219tit o re\u021bea local\u0103 pentru 24 de dispozitive.<\/p>\n<p><\/p>\n<p>\u0218i dac\u0103 ai un alt router l\u0103sat deoparte, po\u021bi activa modul switch \u00een interfa\u021ba sa web \u0219i s\u0103-l folose\u0219ti \u0219i ca switch.<\/p>\n<p><\/p>\n<p><strong>v) Hub<\/strong><\/p>\n<p><\/p>\n<p><strong>Hub<\/strong> \u00eendepline\u0219te acelea\u0219i func\u021bii ca un switch. Dar tehnologia sa de distribu\u021bie este foarte \u00eenvechit\u0103 \u0219i dep\u0103\u0219it\u0103.<\/p>\n<p><\/p>\n<p><img decoding=\"async\" alt=\"Re\u021bele pentru \u00eencep\u0103torii \u00een IT. O baz\u0103 obligatorie.\" src=\"\/wp-content\/uploads\/2020\/03\/12a94370b061caab87a7fba6222835eb.jpg\" style=\"display:block;margin: 0 auto;\" \/><\/p>\n<p><\/p>\n<p><strong>Hub<\/strong> distribuie pachetele care vin de la router tuturor dispozitivelor conectate f\u0103r\u0103 discriminare, iar dispozitivele trebuie s\u0103 determine dac\u0103 este pachetul lor sau nu.<\/p>\n<p><\/p>\n<p>Un <strong>un switch are o tabel\u0103 MAC<\/strong> \u0219i, prin urmare, distribuie pachetele primite unui singur dispozitiv specific care a solicitat acest pachet. Prin urmare <strong>transferul de date<\/strong> prin switch <strong>este mai rapid \u0219i mai eficient<\/strong>.<\/p>\n<p><\/p>\n<p>\u00cen prezent, rar \u00eent\u00e2lne\u0219ti utilizarea <strong>hub-ului<\/strong>, dar totu\u0219i mai exist\u0103, trebuie s\u0103 fim preg\u0103ti\u021bi pentru aceasta \u0219i s\u0103 recomand\u0103m utilizatorului \u00eenlocuirea hub-ului cu un switch.<\/p>\n<p><\/p>\n<h3 id=\"6-osnovnye-komandy-dlya-analiza-seti\">6. Comenzi principale pentru analiza re\u021belei<\/h3>\n<p><\/p>\n<p><strong>a) Comanda Ping<\/strong><\/p>\n<p><\/p>\n<p>Pentru a verifica dac\u0103 un ip-adres\u0103 sau dispozitivul \u00een sine este activ, \u00eel putem \u201epingui\u201d.<br \/>\nPentru aceasta, \u00een linia de comand\u0103 introducem comanda ping \u201c<strong>ip-adres\u0103<\/strong>\u201d.<\/p>\n<p><\/p>\n<p><img decoding=\"async\" alt=\"Re\u021bele pentru \u00eencep\u0103torii \u00een IT. O baz\u0103 obligatorie.\" src=\"\/wp-content\/uploads\/2020\/03\/e89bfc71fc31391bf5f29e8143f0c9b3.jpg\" style=\"display:block;margin: 0 auto;\" \/><\/p>\n<p><\/p>\n<p>Aici am \u201epinguit\u201d serverul DNS google \u0219i, dup\u0103 cum vedem, serverul este activ (r\u0103spuns la pinguri exist\u0103 \u0219i este de 83 ms).<\/p>\n<p><\/p>\n<p>Dac\u0103 destinatarul nu este disponibil sau aceast\u0103 ip-adres\u0103 nu exist\u0103, atunci vom vedea aceast\u0103 imagine:<\/p>\n<p><\/p>\n<p><img decoding=\"async\" alt=\"Re\u021bele pentru \u00eencep\u0103torii \u00een IT. O baz\u0103 obligatorie.\" src=\"\/wp-content\/uploads\/2020\/03\/e7063b58e46bdbd46d6f71ce6b55c082.jpg\" style=\"display:block;margin: 0 auto;\" \/><\/p>\n<p><\/p>\n<p>Adic\u0103 nu primim r\u0103spunsuri la pinguri.<\/p>\n<p><\/p>\n<p>Dar <strong>Ping<\/strong> este mult mai util s\u0103 folose\u0219ti cu cheile:<br \/>\n<strong>-t<\/strong> -\u201cpingui\u201d continuu (pentru a opri, ap\u0103s\u0103m combina\u021bia Ctrl+C)<br \/>\n<strong>-\u0430<\/strong> -afi\u0219eaz\u0103 numele nodului \u201epinguit\u201d (site\/dispozitiv\/server)<\/p>\n<p><\/p>\n<p><img decoding=\"async\" alt=\"Re\u021bele pentru \u00eencep\u0103torii \u00een IT. O baz\u0103 obligatorie.\" src=\"\/wp-content\/uploads\/2020\/03\/fd07bfa3e782a742dac73c53fd4545e7.jpg\" style=\"display:block;margin: 0 auto;\" \/><\/p>\n<p><\/p>\n<p>Prin urmare, cheia \u201c<strong>-\u0430<\/strong>\u201d ne-a ar\u0103tat c\u0103 numele nodului pinguit este \u201cdns.google\u201d.<br \/>\n\u0218i datorit\u0103 cheii \u201c<strong>-t<\/strong>\u201d ping-ul a fost continuu, l-am oprit ap\u0103s\u00e2nd Ctrl+C.<\/p>\n<p><\/p>\n<p>\u00cen timpul ping-ului continuu, putem vedea dac\u0103 nodul pinguit se comport\u0103 adecvat \u0219i calitatea aproximativ\u0103 a lucrului re\u021belei de internet.<\/p>\n<p><\/p>\n<p>Dup\u0103 cum se poate vedea din captura de ecran, apar \u00eent\u00e2rzieri periodice de primire a pachetelor de p\u00e2n\u0103 la 418 ms, ceea ce este o valoare critic\u0103, deoarece saltul de la 83 ms la 418 ms s-ar reflecta \u00een videoconferin\u021be prin \u00eent\u00e2rzieri\/blocaje ale imaginii sau \u00een telefonia ip, degrad\u00e2nd calitatea vocii.<\/p>\n<p><\/p>\n<p>\u00cen cazul meu, cel mai probabil este c\u0103 internetul meu de acas\u0103 are probleme.<br \/>\nDar pentru a determina mai detaliat cauza, trebuie s\u0103 se ruleze un dump. \u0218i aceasta este o tem\u0103 pentru un \u00eentreg articol.<\/p>\n<p><\/p>\n<p><strong>Aten\u021bie!<\/strong> Uneori, pe routere, este dezactivat\u0103 trimiterea <strong>ICMP<\/strong> pachete (cineva le dezactiveaz\u0103 \u00een mod special, iar \u00een alte cazuri nu sunt activate implicit), \u00een acest caz, un astfel de nod nu va r\u0103spunde la \"ping-uri\", de\u0219i va fi activ \u0219i va func\u021biona normal \u00een re\u021bea.<\/p>\n<p><\/p>\n<p>O alt\u0103 posibilitate de \u201eping\u201d este <strong>afla ce adres IP se ascunde \u00een spatele domeniului site-ului<\/strong>. Mai exact, pe ce server este g\u0103zduit site-ul.<\/p>\n<p><\/p>\n<p>Pentru aceasta, pur \u0219i simplu \u00eenlocuim adresa IP cu site-ul:<\/p>\n<p><\/p>\n<p><img decoding=\"async\" alt=\"Re\u021bele pentru \u00eencep\u0103torii \u00een IT. O baz\u0103 obligatorie.\" src=\"\/wp-content\/uploads\/2020\/03\/77b922673c1b0b8cce058934dbc7ef17.jpg\" style=\"display:block;margin: 0 auto;\" \/><\/p>\n<p><\/p>\n<p>Dup\u0103 cum vede\u021bi, la Habr, adresa IP este <strong>178.248.237.68<\/strong><\/p>\n<p><\/p>\n<p><strong>b) Traceroute<\/strong><\/p>\n<p><\/p>\n<p>Uneori este foarte important s\u0103 vedem pe ce drum merge pachetul p\u00e2n\u0103 la un anumit dispozitiv.<br \/>\nPoate c\u0103 undeva exist\u0103 o bre\u0219\u0103 \u0219i pachetul nu ajunge la destinatar. A\u0219adar, <strong>utilitarul traceroute ajut\u0103 la determinarea \u00een ce moment acest pachet se blocheaz\u0103<\/strong>.<\/p>\n<p><\/p>\n<p>Pe sistemele de operare Windows, acest utilitar este apelat cu comanda <strong>\u201ctracert\u201d adresa IP<\/strong> sau domeniul:<\/p>\n<p><\/p>\n<p><img decoding=\"async\" alt=\"Re\u021bele pentru \u00eencep\u0103torii \u00een IT. O baz\u0103 obligatorie.\" src=\"\/wp-content\/uploads\/2020\/03\/4006619ff3ec5292996dc6b1a17cb9c9.jpg\" style=\"display:block;margin: 0 auto;\" \/><\/p>\n<p><\/p>\n<p>Aici am v\u0103zut prin ce noduri trece cererea noastr\u0103, \u00eenainte de a ajunge la serverul ya.ru<\/p>\n<p><\/p>\n<p>Pe <strong>OS Linux<\/strong> acest utilitar este apelat cu comanda <strong>traceroute<\/strong>.<\/p>\n<p><\/p>\n<p>Utilitarul traceroute este de asemenea disponibil pe unele dispozitive, routere sau gate-uri VoIP.<\/p>\n<p><\/p>\n<p><strong>c) Utilitarul whois<\/strong><\/p>\n<p><\/p>\n<p>Acest <strong>utilitar permite ob\u021binerea tuturor informa\u021biilor despre adresa IP sau despre registrarul domeniului,<\/strong>.<\/p>\n<p><\/p>\n<p>De exemplu, s\u0103 verific\u0103m <strong>adresa IP 145.255.1.71<\/strong>. Pentru aceasta, introduc \u00een terminal comanda <strong>whois 145.255.1.71<\/strong><\/p>\n<p><\/p>\n<p><img decoding=\"async\" alt=\"Re\u021bele pentru \u00eencep\u0103torii \u00een IT. O baz\u0103 obligatorie.\" src=\"\/wp-content\/uploads\/2020\/03\/45b6cc235a41aa85781437b131a6ed1c.jpg\" style=\"display:block;margin: 0 auto;\" \/><\/p>\n<p><\/p>\n<p>Am ob\u021binut informa\u021bii despre providerul adresei IP, \u021bara, ora\u0219ul, adresa, intervalul etc.<\/p>\n<p><\/p>\n<p>O folosesc doar pe Linux. Utilitarul se descarc\u0103 \u0219i se instaleaz\u0103 u\u0219or din depozitul standard al sistemului de operare.<\/p>\n<p><\/p>\n<p>Dar am citit c\u0103 exist\u0103 o solu\u021bie similar\u0103 \u0219i pe Windows.<\/p>\n<p><\/p>\n<h3 id=\"7-transportnye-protokoly-tcp-i-udp\">7. Protocoalele de transport TCP \u0219i UDP<\/h3>\n<p><\/p>\n<p>Toate transmisiile de cereri \u0219i primirea r\u0103spunsurilor \u00eentre dispozitive \u00een re\u021bea se realizeaz\u0103 prin protocoale de transport <strong>TCP \u0219i UDP<\/strong>.<\/p>\n<p><\/p>\n<p><strong>Protocolul TCP garanteaz\u0103 livrarea cererii \u0219i integritatea transmisiei sale.<\/strong> Acesta verific\u0103 disponibilitatea nodului \u00eenainte de a trimite pachetul. Iar dac\u0103 pe parcurs integritatea pachetului este compromis\u0103, atunci <strong>TCP<\/strong> completeaz\u0103 componentele lips\u0103.<\/p>\n<p><\/p>\n<p>\u00cen general, acest protocol va face tot ce este necesar pentru ca cererea dvs. s\u0103 ajung\u0103 corect la destinatar.<\/p>\n<p><\/p>\n<p>De aceea <strong>TCP<\/strong> este cel mai r\u0103sp\u00e2ndit protocol de transport. Este folosit atunci c\u00e2nd utilizatorul navigheaz\u0103 pe internet, viziteaz\u0103 site-uri, servicii, re\u021bele sociale etc.<\/p>\n<p><\/p>\n<p><img decoding=\"async\" alt=\"Re\u021bele pentru \u00eencep\u0103torii \u00een IT. O baz\u0103 obligatorie.\" src=\"\/wp-content\/uploads\/2020\/03\/482b66a00f5ea2b73d5e099dccbfddc1.jpg\" style=\"display:block;margin: 0 auto;\" \/><\/p>\n<p><\/p>\n<p><strong>UDP<\/strong> protocolul nu are o livrare a datelor garantat\u0103, precum <strong>TCP<\/strong>. Acesta nu verific\u0103 disponibilitatea nodului final \u00eenainte de trimitere \u0219i nu compenseaz\u0103 pachetul \u00een caz de degradare. Dac\u0103 un anumit pachet sau c\u00e2teva pachete sunt pierdute pe drum, mesajul va ajunge la destinatar \u00eentr-o form\u0103 incomplet\u0103.<\/p>\n<p><\/p>\n<p><strong>De ce este necesar UDP atunci?<\/strong><\/p>\n<p><\/p>\n<p>Pe scurt, acest protocol de transport are un avantaj enorm fa\u021b\u0103 de <strong>TCP<\/strong> \u00een viteza de transfer al datelor. Prin urmare, <strong>UDP este folosit pe scar\u0103 larg\u0103 pentru a trimite pachete de voce \u0219i video \u00een timp real<\/strong>. \u00cen special, \u00een VoIP \u0219i apeluri video.<br \/>\nDe exemplu, orice apel prin WhatsApp sau Viber folose\u0219te protocolul de transport <strong>UDP<\/strong>. La fel \u0219i \u00een apelurile video, de exemplu, prin Skype sau acelea\u0219i aplica\u021bii de mesagerie WhatsApp \u0219i Viber.<\/p>\n<p><\/p>\n<p><img decoding=\"async\" alt=\"Re\u021bele pentru \u00eencep\u0103torii \u00een IT. O baz\u0103 obligatorie.\" src=\"\/wp-content\/uploads\/2020\/03\/16ba70a967deca02cd1309e34a887935.jpg\" style=\"display:block;margin: 0 auto;\" \/><\/p>\n<p><\/p>\n<p>Exact din cauza c\u0103 UDP nu garanteaz\u0103 transferul absolut al datelor \u0219i integritatea pachetului transmis, adesea apar probleme \u00een timpul apelurilor prin internet.<br \/>\nAcestea includ \u00eentreruperea vocii, \u00eent\u00e2rzieri, ecou sau un ton robotic. <\/p>\n<p><\/p>\n<p>Aceast\u0103 problem\u0103 apare din cauza unei conexiuni de internet suprasolicitate, a unui NAT dublu sau a unui canal radio.<\/p>\n<p><\/p>\n<p>Ar fi bine, desigur, \u00een astfel de cazuri s\u0103 folosi\u021bi <strong>TCP<\/strong>, dar din p\u0103cate, pentru a transmite vocea este necesar\u0103 o transmisie imediat\u0103 a pachetelor \u00eentregi, iar pentru aceast\u0103 sarcin\u0103 este ideal <strong>UDP<\/strong>. <\/p>\n<p><\/p>\n<p>Pentru a evita problemele \u00een utilizarea <strong>UDP<\/strong> protocolului, trebuie simplu s\u0103 organiza\u021bi un canal de internet de calitate. De asemenea, este necesar s\u0103 configura\u021bi pe router un l\u0103\u021bime de band\u0103 dedicat\u0103 pentru <strong>UDP<\/strong>, astfel \u00eenc\u00e2t \u00eenc\u0103rc\u0103tura de pe alte dispozitive care folosesc <strong>TCP<\/strong> s\u0103 nu interfereze cu func\u021bionarea protocolului de transport. <strong>UDP<\/strong>.<\/p>\n<p><\/p>\n<p><strong>Asta e tot.<\/strong><\/p>\n<p><\/p>\n<p>Nu am vrut s\u0103 aglomerez articolul cu defini\u021bii \u0219tiin\u021bifice ale tuturor termenilor folosi\u021bi, cine are nevoie, poate c\u0103uta pe Google.<\/p>\n<p><\/p>\n<p>Am \u00eencercat s\u0103 str\u00e2ng la un loc cele 7 momente cele mai importante, care, \u00een opinia mea, vor ajuta un \"IT-ist\" t\u00e2n\u0103r s\u0103 treac\u0103 prin primele etape ale interviului pentru posturi \"IT\" sau m\u0103car s\u0103-i arate angajatorului c\u0103 \u0219ti\u021bi clar mai mult dec\u00e2t un utilizator obi\u0219nuit.<\/p>\n<p><\/p>\n<p>Studia\u021bi, lua\u021bi noti\u021be. Sper c\u0103 articolul le va aduce multora un folos.<\/p>\n<p>Sursa: <a content=\"nofollow\" rel=\"nofollow\" href=\"https:\/\/habr.com\/ru\/post\/491540\/\">habr.com<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"<p>\u041f\u0440\u0438\u043c\u0435\u0440\u043d\u043e 80% \u0438\u0437 \u043d\u0430\u0441, \u043a\u0442\u043e \u0437\u0430\u043a\u0430\u043d\u0447\u0438\u0432\u0430\u0435\u0442 \u0443\u043d\u0438\u0432\u0435\u0440\u0441\u0438\u0442\u0435\u0442 \u0441 \u043a\u0430\u043a\u043e\u0439-\u043b\u0438\u0431\u043e IT-\u0441\u043f\u0435\u0446\u0438\u0430\u043b\u044c\u043d\u043e\u0441\u0442\u044c\u044e, \u0432 \u0438\u0442\u043e\u0433\u0435 \u043d\u0435 \u0441\u0442\u0430\u043d\u043e\u0432\u0438\u0442\u0441\u044f \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u0438\u0441\u0442\u043e\u043c. \u041c\u043d\u043e\u0433\u0438\u0435 \u0443\u0441\u0442\u0440\u0430\u0438\u0432\u0430\u044e\u0442\u0441\u044f \u0432 \u0442\u0435\u0445\u043d\u0438\u0447\u0435\u0441\u043a\u0443\u044e \u043f\u043e\u0434\u0434\u0435\u0440\u0436\u043a\u0443, \u0441\u0438\u0441\u0442\u0435\u043c\u043d\u044b\u043c\u0438 \u0430\u0434\u043c\u0438\u043d\u0438\u0441\u0442\u0440\u0430\u0442\u043e\u0440\u0430\u043c\u0438, \u043c\u0430\u0441\u0442\u0435\u0440\u0430\u043c\u0438 \u043f\u043e \u043d\u0430\u043b\u0430\u0434\u043a\u0435 \u043a\u043e\u043c\u043f\u044c\u044e\u0442\u0435\u0440\u043d\u044b\u0445 \u0443\u0441\u0442\u0440\u043e\u0439\u0441\u0442\u0432, \u043a\u043e\u043d\u0441\u0443\u043b\u044c\u0442\u0430\u043d\u0442\u0430\u043c\u0438-\u043f\u0440\u043e\u0434\u0430\u0432\u0446\u0430\u043c\u0438 \u0446\u0438\u0444\u0440\u043e\u0432\u043e\u0439 \u0442\u0435\u0445\u043d\u0438\u043a\u0438, \u043c\u0435\u043d\u0435\u0434\u0436\u0435\u0440\u0430\u043c\u0438 \u0432 it-\u0441\u0444\u0435\u0440\u0443 \u0438 \u0442\u0430\u043a \u0434\u0430\u043b\u0435\u0435. \u042d\u0442\u0430 \u0441\u0442\u0430\u0442\u044c\u044f \u043a\u0430\u043a \u0440\u0430\u0437 \u0434\u043b\u044f \u0442\u0430\u043a\u0438\u0445 80%, \u043a\u0442\u043e \u0442\u043e\u043b\u044c\u043a\u043e \u0437\u0430\u043a\u043e\u043d\u0447\u0438\u043b \u0443\u043d\u0438\u0432\u0435\u0440\u0441\u0438\u0442\u0435\u0442 \u0441 \u043a\u0430\u043a\u043e\u0439-\u043b\u0438\u0431\u043e IT-\u0441\u043f\u0435\u0446\u0438\u0430\u043b\u044c\u043d\u043e\u0441\u0442\u044c\u044e \u0438 \u0443\u0436\u0435 \u043d\u0430\u0447\u0430\u043b \u043c\u043e\u043d\u0438\u0442\u043e\u0440\u0438\u0442\u044c \u0432\u0430\u043a\u0430\u043d\u0441\u0438\u0438, [&hellip;]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":73868,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[688],"tags":[],"class_list":["post-73867","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-administrirovanie"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 5.0.2.1 - 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