DNS records mu nteaseɛ: A, MX, CNAME, TXT ne nea ɛka ho

Deɛn ne DNS?

DNS (Domain Name System) yɛ internet no phone book. Ɛdan domain names a nnipa tumi kenkan (sɛ nhwɛsoɔ, example.com) ma ɛyɛ IP addresses a computers te aseɛ. DNS records nso kyerɛ saa ɔdan yi mmara.

A record

A (Address) record de domain name kyerɛ IPv4 address. Eyi ne DNS record type a edi kan titriw:

example.com.  IN  A  93.184.216.34

Website biara hia A record biako pɛ mpo.

AAAA record

AAAA record yɛ A record no IPv6 version. IPv6 addresses ware na ɛma address space pii:

example.com.  IN  AAAA  2606:2800:220:1:248:1893:25c8:1946

MX record

MX (Mail Exchange) record kyerɛ server bɛn na ɛbɛgye emails a wɔde kɔma wo domain. Wɔde priority value hyɛ — nɔma a ɛsua no kyerɛ priority a ɛkorɔn:

example.com.  IN  MX  10  mail.evilmail.com.
example.com.  IN  MX  20  mail2.evilmail.com.

CNAME record

CNAME (Canonical Name) record de domain name biako kyerɛ domain name foforɔ. Ɛyɛ adwuma sɛ alias:

www.example.com.  IN  CNAME  example.com.

Wontumi mfa CNAME record mma root domain — subdomains nkutoo.

TXT record

TXT record kora text data biara. Wɔtaa de di dwuma ma email verification protocols te sɛ SPF, DKIM, ne DMARC:

example.com.  IN  TXT  "v=spf1 include:evilmail.com ~all"

NS record

NS (Name Server) record kyerɛ server bɛn na ɛhwɛ domain no DNS so:

example.com.  IN  NS  ns1.evilmail.com.
example.com.  IN  NS  ns2.evilmail.com.

SRV record

SRV (Service) record kyerɛ baabi a services titriw wɔ. Format: priority, weight, port ne target:

_imap._tcp.example.com.  IN  SRV  0 1 993 imap.evilmail.com.

CAA record

CAA (Certification Authority Authorization) record kyerɛ certificate authorities bɛn na wɔbɛtumi ama SSL/TLS certificate ama wo domain:

example.com.  IN  CAA  0 issue "letsencrypt.org"

TTL: Nkwa bere

TTL (Time to Live) kyerɛ bere a wɔbɛkora DNS record wɔ cache mu wɔ seconds mu. TTL a ɛsua (300 seconds) kyerɛ sɛ update bɛyɛ ntɛm, nanso ɛma DNS queries pii ba. TTL a ɛkorɔn (86400 seconds — da 1) kyerɛ sɛ queries sua, nanso nsakraeɛ trɛ brɛoo.

DNS ɔhaw siesie

Sɛ wopɛ sɛ wohwehwɛ DNS ɔhaw mu a, fa saa commands yi di dwuma:

# Hwɛ A record
dig A example.com

# Hwɛ MX record
dig MX example.com

# Hwɛ records nyinaa
dig ANY example.com

# Bisa fi DNS server titriw bi
dig @8.8.8.8 example.com

# Hwɛ DNS propagation
nslookup example.com

Saa commands yi boa wo sɛ wobɛhwɛ sɛ wo DNS configuration yɛ pɛ na woahu ɔhaw biara.