El comando dt es una herramienta bajo licencia Apache 2.0 escrita en Go. Es una herramienta CLI para DNS que muestra información sobre un dominio.
En la actualidad, tiene las siguientes características:
- Soporte de escáner de registros comunes (Tipo A, CNAME, TXT, etc).
- Validación de cadenas DNSSEC.
- Modificar la velocidad de consulta para el escaneo.
- Diagnóstico de un dominio (similar a intodns.com, dnsspy.io).
Instalación de Go en GNU/Linux
Para instalar Go en GNU/Linux debéis de seguir primero este otro tutorial:
Cómo instalar Go (GoLang) en GNU/Linux
Go, también conocido como GoLang, es un lenguaje de programación. Es de código abierto desarrollado por un equipo de Google y muchos otros colaboradores de la comunidad.
Don T3rr0rZ0n3
Instalación de dt
Para la instalación de dt, lo podemos hacer de diferentes formas, si por ejemplo quieres compilar tu mismo el código fuente, puedes visitar su página de GitHub para más detalle.
En este tutorial, lo que haremos será instalarlo usando el instalador de paquetes para Go que descargará el binario y luego deberemos de copiarlo en el directorio correcto.
Lo instalamos:
# go install github.com/42wim/dt@latest
Esto nos generará un directorio llamado go y si vamos a ~/go/bin veremos que tenemos el binario para dt. Ahora para ejecutarlo como un comando más de nuestro sistema operativo, deberemos de hacer lo siguiente:
# cp ~/go/bin/dt /usr/bin/
Uso de dt
Si ejecutamos el comando sin ningún parámetro, nos aparecerá la ayuda con los parámetros que dispone este software de DNS.
# dt
Usage:
dt [FLAGS] domain
Example:
dt icann.org
dt -debug ripe.net
dt -debug -scan yourdomain.com
Flags:
-debug
enable debug
-json
output in JSON
-qps int
queries per seconds (per nameserver) (default 10)
-resolver string
use this resolver for initial domain lookup (default "8.8.8.8")
-scan
scan domain for common records
-showfail
only show checks that fail or warn
Podemos usar el comando con el nombre de dominio que queremos que nos de la información de DNS, por ejemplo:
# dt stallman.org
using 8.8.8.8 as resolver
NS |IP |LOC |ASN |ISP |rtt |Serial
dns1.positive-internet.com. |80.87.136.65 |GB |AS21260 |POSITIVE-INTERNET-UK-AS, GB |42.587791ms |2019102101 |
dns0.positive-internet.com. |80.87.128.65 |GB |AS21260 |POSITIVE-INTERNET-UK-AS, GB |46.895502ms |2019102101 |
NS |IP |Version |DNSSEC |ValidFrom |ValidUntil
dns1.positive-internet.com. |80.87.136.65 |PowerDNS Authoritative Server 4.4.0 (built Dec 17 2020 12:40:00 by root@4b136b7c185f) |valid |1 week ago |1 week from now
dns0.positive-internet.com. |80.87.128.65 |PowerDNS Authoritative Server 4.4.0 (built Dec 17 2020 12:40:00 by root@4b136b7c185f) |valid |1 week ago |1 week from now
..
stallman.org. 10799 IN NS dns1.positive-internet.com.
stallman.org. 10799 IN NS dns0.positive-internet.com.
NS
OK : NS of all nameservers are identical
OK : Multiple nameservers found
OK : Your nameservers are in different subnets.
WARN: Nameservers are all on the same AS (AS21260). This is a single point of failure.
WARN: No IPv6 nameservers found. IPv6-only users will have problems.
OK : All nameservers are authoritative.
OK : All nameservers report they are not allowing recursive queries.
OK : Your nameservers are also listed as NS at the parent nameservers
OK : Your parent nameservers are also listed as NS at your nameservers
OK : No CNAMEs found for your NS records
GLUE
WARN: no glue records found for [80.87.128.65 80.87.136.65] in NS of parent org.
WARN: no glue records found for [80.87.128.65 80.87.136.65] in NS of stallman.org.
SOA
OK : SOA of all nameservers are identical
OK : MNAME dns0.positive-internet.com. is listed at the parent servers.
OK : Your nameservers have public / routable addresses.
MX
OK : MX of all nameservers are identical
WARN: Only 1 MX record found. Extra records increases reliability
OK : Your MX records have public / routable addresses.
OK : Your MX records resolve to different ips.
OK : No CNAMEs found for your MX records
OK : All MX records have reverse PTR records
Web
OK : Found a www record
OK : Found a root record
OK : Didn't find a CNAME for the root record
OK : Your www record has a public / routable address.
Spam
WARN: No DMARC records found. Along with DKIM and SPF, DMARC helps prevent spam from your domain.
WARN: No SPF records found. Along with DKIM and DMARC, SPF helps prevent spam from your domain.
DNSSEC
OK : DNSKEY validated. Chain validated
Podemos también ejecutar con el parámetro -scan para que al final del comando nos dé más información de los registros:
# dt -scan stallman.org
.. 80.87.136.65 AXFR denied
. *.stallman.org. 300 IN A 80.87.128.67
stallman.org. 10643 IN NS dns0.positive-internet.com.
stallman.org. 10643 IN NS dns1.positive-internet.com.
stallman.org. 10645 IN MX 0 cannonball.positive-internet.com.
stallman.org. 10645 IN SOA dns0.positive-internet.com. hostmaster.positive-internet.com. 2019102101 3600 1800 1814400 3600
stallman.org. 145 IN A 216.116.72.174
stallman.org. 3443 IN DNSKEY 257 3 13 9RLVIYhKwnkPomKb1DLQvgwFZtLJG2y5tg6dNvh+0VseHhBrwX6ALbaL3km27oUtDrCpv9IGVgblFETn9xI3+Q==
www.stallman.org. 300 IN A 216.116.72.174
Scan took 1m20.093515057s
O incluso se puede sacar en formato JSON con -json:
# dt -json stallman.org
{"Name":"stallman.org","NSInfo":[{"Name":"dns1.positive-internet.com.","Rtt":39902537,"Serial":2019102101,"IP":"80.87.136.65","Loc":"GB","ASN":21260,"ISP":"POSITIVE-INTERNET-UK-AS, GB","Valid":true,"ChainValid":false,"Disabled":false,"Start":1636588800,"End":1638403200,"Version":"PowerDNS Authoritative Server 4.4.0 (built Dec 17 2020 12:40:00 by root@4b136b7c185f)"},{"Name":"dns0.positive-internet.com.","Rtt":47447451,"Serial":2019102101,"IP":"80.87.128.65","Loc":"GB","ASN":21260,"ISP":"POSITIVE-INTERNET-UK-AS, GB","Valid":true,"ChainValid":false,"Disabled":false,"Start":1636588800,"End":1638403200,"Version":"PowerDNS Authoritative Server 4.4.0 (built Dec 17 2020 12:40:00 by root@4b136b7c185f)"}],"Timestamp":"2021-11-24T13:31:00.000233886+01:00","Report":[{"Type":"NS","Result":[{"Result":"FAIL: NS not identical\t [80.87.128.65]\n\t stallman.org.\t10514\tIN\tNS\tdns0.positive-internet.com.\n\t stallman.org.\t10514\tIN\tNS\tdns1.positive-internet.com.\n\t \n\t [80.87.136.65]\n\t stallman.org.\t10513\tIN\tNS\tdns0.positive-internet.com.\n\t stallman.org.\t10513\tIN\tNS\tdns1.positive-internet.com.\n\t \n","Status":false,"Error":"","Records":null,"Name":"Identical"},{"Result":"OK : Multiple nameservers found","Status":true,"Error":"","Records":["stallman.org.\t10514\tIN\tNS\tdns1.positive-internet.com.","stallman.org.\t10514\tIN\tNS\tdns0.positive-internet.com."],"Name":"Multiple"},{"Result":"OK : Your nameservers are in different subnets.","Status":true,"Error":"","Records":null,"Name":"Subnet"},{"Result":"WARN: Nameservers are all on the same AS (AS21260). This is a single point of failure.","Status":false,"Error":"","Records":null,"Name":"MultipleAS"},{"Result":"WARN: No IPv6 nameservers found. IPv6-only users will have problems.","Status":false,"Error":"","Records":null,"Name":"IPv6"},{"Result":"OK : All nameservers are authoritative.","Status":true,"Error":"","Records":null,"Name":"Auth"},{"Result":"OK : All nameservers report they are not allowing recursive queries.","Status":true,"Error":"","Records":null,"Name":"Recursive"},{"Result":"OK : Your nameservers are also listed as NS at the parent nameservers","Status":true,"Error":"","Records":null,"Name":"ParentListed"},{"Result":"OK : Your parent nameservers are also listed as NS at your nameservers","Status":true,"Error":"","Records":null,"Name":"SelfListed"},{"Result":"OK : No CNAMEs found for your NS records","Status":true,"Error":"","Records":null,"Name":"CNAME"}]},{"Type":"GLUE","Result":[{"Result":"WARN: no glue records found for [80.87.128.65 80.87.136.65] in NS of parent org.","Status":false,"Error":"","Records":null,"Name":"Parent"},{"Result":"WARN: no glue records found for [80.87.128.65 80.87.136.65] in NS of stallman.org.","Status":false,"Error":"","Records":null,"Name":"Self"}]},{"Type":"SOA","Result":[{"Result":"OK : SOA of all nameservers are identical","Status":true,"Error":"","Records":null,"Name":"Identical"},{"Result":"OK : MNAME dns0.positive-internet.com. is listed at the parent servers.","Status":true,"Error":"","Records":null,"Name":"MNAME"},{"Result":"OK : Your nameservers have public / routable addresses.","Status":true,"Error":"","Records":null,"Name":"RFC1918"}]},{"Type":"MX","Result":[{"Result":"OK : MX of all nameservers are identical","Status":true,"Error":"","Records":null,"Name":"Identical"},{"Result":"WARN: Only 1 MX record found. Extra records increases reliability","Status":false,"Error":"","Records":null,"Name":"Multiple"},{"Result":"OK : Your MX records have public / routable addresses.","Status":true,"Error":"","Records":null,"Name":"RFC1918"},{"Result":"OK : Your MX records resolve to different ips.","Status":true,"Error":"","Records":null,"Name":"DuplicateIP"},{"Result":"OK : No CNAMEs found for your MX records","Status":true,"Error":"","Records":null,"Name":"CNAME"},{"Result":"OK : All MX records have reverse PTR records","Status":true,"Error":"","Records":null,"Name":"Reverse"}]},{"Type":"Web","Result":[{"Result":"OK : Found a www record","Status":true,"Error":"","Records":null,"Name":"WWW"},{"Result":"OK : Found a root record","Status":true,"Error":"","Records":null,"Name":"Apex"},{"Result":"OK : Didn't find a CNAME for the root record","Status":true,"Error":"","Records":null,"Name":"ApexCNAME"},{"Result":"OK : Your www record has a public / routable address.","Status":true,"Error":"","Records":null,"Name":"RFC1918"}]},{"Type":"Spam","Result":[{"Result":"WARN: No DMARC records found. Along with DKIM and SPF, DMARC helps prevent spam from your domain.","Status":false,"Error":"","Records":null,"Name":"DMARC"},{"Result":"WARN: No SPF records found. Along with DKIM and DMARC, SPF helps prevent spam from your domain.","Status":false,"Error":"","Records":null,"Name":"SPF"}]},{"Type":"DNSSEC","Result":[{"Result":"OK : DNSKEY validated. Chain validated","Status":true,"Error":"","Records":null,"Name":"DNSSEC"}]}],"Scan":null}
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