DNS yɛ layer a ɛwɔ ase a ɛma internet yɛ adwuma, nanso domain wura dodoɔ so no ntumi nka ne ho asɛm gye sɛ biribiara asɛe. Sɛ yɛahwɛ DNS nhyehyɛeɛ so ama domain mpempem wɔ yɛn platform so wieɛ no, yɛaboaboa saa nkyerɛkyerɛmu yi ano sɛnea wɔbɛgye wo afiri sɔhwɛ a ɛsɛe bere mu.
A Records — Fapemdeɛ No A record de domain din hyia IPv4 address. Ɛyɛ DNS record a ɛyɛ mmerɛ paa na wo browser de hwehwɛ web server. Sɛ wohyɛ example.com wɔ browser mu a, DNS resolver hwehwɛ A record no sɛnea ɛbɛhwehwɛ IP address a website no wɔ. Wobɛtumi anya A record pii ama domain koro sɛnea ɛbɛkyɛ adwuma mu. ``` example.com. IN A 203.0.113.50 example.com. IN A 203.0.113.51 ```
AAAA Records — IPv6 Sɛso Ɛyɛ adwuma te sɛ A record ara, nanso ɛkyerɛ IPv6 address na ɛnyɛ IPv4. Sɛ IPv6 dwumadie nyin a, sɛ wowɔ A ne AAAA record abien no, ɛma wo domain wɔ kwan firi network biara so. ``` example.com. IN AAAA 2001:db8::1 ```
MX Records — Email Fapemdeɛ MX (Mail Exchange) records ho hia ma email delivery. Wɔka kyerɛ mail server a ɛretwerɛ sɛ ɛnfa email no kɔ he ma wo domain. Priority number no ho hia — nea ɛsua no na ɛdi kan. Nhyehyɛeɛ a ɛtaa yɛ a backup server wɔ mu bɛhwɛ sɛ eyi: ``` example.com. IN MX 10 mail.example.com. example.com. IN MX 20 backup.example.com. ```
Sɛ wohyehyɛ domain wɔ EvilMail mu a, wɔyɛ MX records ankasa sɛnea email bɛba yɛn server so. MX records a wɔanhyehyɛ papa ne adeɛ titiriw a ɛma email yera — hwɛ mu daa sɛ wosakra DNS biara a.
CNAME Records — Din Foforɔ CNAME (Canonical Name) record yɛ din foforɔ a ɛfiri domain din biako kɔ foforɔ. Wɔtaa de kyerɛ subdomain ahorow kɔ external service. Sɛ nhwɛsoɔ no, fa wo blog subdomain kɔ hosted platform: ``` blog.example.com. IN CNAME your-site.ghost.io. ```
Hwɛ yie: CNAME records ntumi nntra ne record foforɔ wɔ din koro so. Wontumi nnya CNAME ne MX record amma subdomain koro. Eyi yɛ DNS nhyehyɛeɛ mmara, ɛnyɛ provider biara anohyetoɔ.
TXT Records — Nhwɛsoɔ ne Ahobammɔ TXT records kora nkyerɛwdeɛ nsɛm na ɛyɛ adwuma ahodoɔ wɔ nnɛ DNS mu. Nea wɔtaa de di dwuma ne domain nhwɛsoɔ (sɛdeɛ wode bɛkyerɛ Google, Microsoft, anaa service foforɔ sɛ domain no yɛ wo dea), SPF records ma email authentication, ne DKIM signatures. SPF record a ɛma EvilMail kwan sɛ ɛtwerɛ email ma wo bɛhwɛ sɛ eyi: ``` example.com. IN TXT "v=spf1 include:evilmail.pro ~all" ```
NS Records — Tumi a Wɔde Ma NS (Name Server) records kyerɛ DNS server bɛn na ɛwɔ tumi wɔ wo domain so. Sɛ wokyerɛw domain wɔ EvilMail na wode wo nameservers kɔ yɛn nhyehyɛeɛ so a, woresa NS records a ɛwɔ wo registrar hɔ no de tumi ama yɛn server: ``` example.com. IN NS storm.nesil.dev. example.com. IN NS void.nesil.dev. example.com. IN NS kraken.nesil.dev. example.com. IN NS pandora.nesil.dev. ```
SRV Records — Service Beaeɛ SRV records kyerɛ service ahodoɔ beaeɛ. Protocol te sɛ SIP, XMPP, ne LDAP de di dwuma. Nhyehyɛeɛ no bi ne service din, protocol, priority, weight, port, ne target: ``` _sip._tcp.example.com. IN SRV 10 60 5060 sipserver.example.com. ```
CAA Records — Certificate Authority Kwan CAA records kyerɛ Certificate Authority bɛn na ɛwɔ kwan sɛ ɛyɛ SSL certificate ma wo domain. Eyi yɛ ahobammɔ nhyehyɛeɛ a ɛsiw certificate a wɔamma kwan kwan: ``` example.com. IN CAA 0 issue "letsencrypt.org" ```
TTL — Bere a Ɛtena Ase DNS record biara wɔ TTL a wɔsusu wɔ seconds mu. Eyi ka kyerɛ DNS resolver bere a ɛsɛ sɛ ɛkora record no so ansa na ɛsan abisa server no bio. TTL a ɛsua (seconds 300) kyerɛ sɛ nsakraeɛ bɛtrɛw ntɛm nanso DNS query bɛyɛ pii. TTL a ɛdɔɔso (seconds 86400) tew query so nanso ɛma nsakraeɛ kyɛ. Ansa na woayɛ DNS nsakraeɛ titiriw a, tew wo TTL dɔnhwerew 24 ansa na cache dedaw no aba awieɛ ntɛm.
DNS Teetee Mu Yɛ Sɛ biribiara nyɛ adwuma a, hwɛ wo records firi baabi ahodoɔ. Fa dig hwɛ firi command-line: ``` dig +short MX example.com dig +short A example.com dig +short TXT example.com ```
Sɛ records no hwɛ papa nanso email da so nyɛ adwuma a, kae sɛ DNS propagation nyɛ ntɛm. Records foforɔ bɛtumi agyɛ dɔnhwerew 48 ansa na wiase nyinaa ahu, sɛdeɛ TTL ne resolver caching teɛ. Boasetɔ, wɔ DNS nhyehyɛeɛ mu, yɛ adeɛ a ɛhia ampa.