Eu tentei configurar uma pesquisa de DNS no CentOS 7 (em uma VM de caixa virtual), que funciona para o FQDN na mesma máquina virtual que o DNS. No entanto, quando tento resolver o nome do host curto, ele falha.
Eu já vi isso funcionando em alguns servidores e queria aprender como configurá-lo sozinho. Aprecie qualquer ajuda sobre isso.
Abaixo estão as configurações:
Arquivo - /etc/named.conf
//
// named.conf
//
options {
listen-on port 53 { 127.0.0.1; 192.168.56.101; };
listen-on-v6 port 53 { ::1; };
directory "/var/named";
dump-file "/var/named/data/cache_dump.db";
statistics-file "/var/named/data/named_stats.txt";
memstatistics-file "/var/named/data/named_mem_stats.txt";
allow-query { localhost; 192.168.0.0/24; };
allow-transfer { localhost; 192.168.56.101; };
recursion yes;
dnssec-enable yes;
dnssec-validation yes;
dnssec-lookaside auto;
/* Path to ISC DLV key */
bindkeys-file "/etc/named.iscdlv.key";
managed-keys-directory "/var/named/dynamic";
pid-file "/run/named/named.pid";
session-keyfile "/run/named/session.key";
};
logging {
channel default_debug {
file "data/named.run";
severity dynamic;
};
};
zone "." IN {
type hint;
file "named.ca";
};
zone "eai.com" IN {
type master;
file "forward.linuxzadmin";
allow-update { none; };
};
zone "0.168.192.in-addr.arpa" IN {
type master;
file "reverse.linuxzadmin";
allow-update { none; };
};
include "/etc/named.rfc1912.zones";
include "/etc/named.root.key";
Arquivo - /etc/resolv.conf
# Generated by NetworkManager
# nameserver 169.144.126.136
# nameserver 146.11.115.200
# nameserver 153.88.112.200
# NOTE: the libc resolver may not support more than 3 nameservers.
# The nameservers listed below may not be recognized.
# nameserver 147.128.170.138
# nameserver 127.0.0.1
nameserver 192.168.56.101
Arquivo - / etc / hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.56.101 eai16.eai.com eai16 eai16-oam
Arquivo - /var/named/forward.linuxzadmin
$TTL 86400
@ IN SOA masterdns.eai.com. root.eai.com. (
2014051001 ; serial
3600 ; refresh
1800 ; retry
604800 ; expire
86400 ; minimum
)
@ IN NS masterdns.eai.com.
@ IN A 192.168.56.101
masterdns IN A 192.168.56.101
node1 IN A 192.168.56.101
eai16 IN A 192.168.56.101
Arquivo - /var/named/reverse.linuxzadmin
$TTL 86400
@ IN SOA masterdns.eai.com. root.eai.com. (
2014051001 ; serial
3600 ; refresh
1800 ; retry
604800 ; expire
86400 ; minimum
)
@ IN NS masterdns.eai.com.
@ IN PTR eai.com.
masterdns IN A 192.168.56.101
node1 IN A 192.168.56.101
eai16 IN A 192.168.56.101
101 IN PTR masterdns.eai.com.
101 IN PTR node1.eai.com.
101 IN PTR eai16.eai.com.
101 IN PTR eai16.
Saída de comando
Nome do host
[root@eai16 etc]# hostname -f
eai16.eai.com
[root@eai16 etc]# hostname -s
eai16
Pesquisa NS no FQDN
[root@eai16 etc]# nslookup eai16.eai.com
Server: 192.168.56.101
Address: 192.168.56.101#53
Name: eai16.eai.com
Address: 192.168.56.101
Dig no FQDN
[root@eai16 etc]# dig eai16.eai.com
; <<>> DiG 9.9.4-RedHat-9.9.4-38.el7_3.3 <<>> eai16.eai.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 62927
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 2
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;eai16.eai.com. IN A
;; ANSWER SECTION:
eai16.eai.com. 86400 IN A 192.168.56.101
;; AUTHORITY SECTION:
eai.com. 86400 IN NS masterdns.eai.com.
;; ADDITIONAL SECTION:
masterdns.eai.com. 86400 IN A 192.168.56.101
;; Query time: 0 msec
;; SERVER: 192.168.56.101#53(192.168.56.101)
;; WHEN: Wed Jun 28 21:13:38 IST 2017
;; MSG SIZE rcvd: 98
Host no FQDN
[root@eai16 etc]# host eai16.eai.com
eai16.eai.com has address 192.168.56.101
[root@eai16 etc]# host 'hostname'
eai16.eai.com has address 192.168.56.101
Agora, todos os comandos (nslookup, dig e host) falham no nome abreviado do host.
[root@eai16 etc]# host eai16
Host eai16 not found: 2(SERVFAIL)
[root@eai16 etc]# host eai16
;; connection timed out; no servers could be reached
[root@eai16 etc]# nslookup eai16
Server: 192.168.56.101
Address: 192.168.56.101#53
** server can't find eai16: SERVFAIL
[root@eai16 etc]# dig eai16
; <<>> DiG 9.9.4-RedHat-9.9.4-38.el7_3.3 <<>> eai16
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 23006
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;eai16. IN A
;; Query time: 0 msec
;; SERVER: 192.168.56.101#53(192.168.56.101)
;; WHEN: Wed Jun 28 21:25:18 IST 2017
;; MSG SIZE rcvd: 34
Eu sei que algo está faltando / errado na minha configuração, mas não consigo descobrir o que é.
O problema está na configuração resolv.conf / DHCP se o resolv.conf não for estático.
Você precisa adicionar à diretiva search de resolv.conf do domínio eai.com
Quando você tenta uma pesquisa de nome DNS, as bibliotecas do resolvedor, se não obtiverem êxito, tentam alternadamente resolver o nome adicionando os domínios na diretiva de pesquisa até encontrarem um nome resolvível ou até esgotarem a lista de domínios na diretiva de pesquisa .