Perdiendo conectividad con DNS

Perdiendo conectividad con DNS

Configuré un DNS 'interno' en mi trabajo, básicamente tenemos un nombre de dominio ejemplo.com que es para Internet, correo electrónico, etc. y he creado en uno de nuestros servidores de red Linux (debian) un DNS usando bind9 con el dominio. ejemplo.inc.

Según mis archivos a continuación y los síntomas que describo; ¿Qué puedo hacer para arreglar esto?

Estos son los archivos críticos (creo) que he modificado:

nombrado.conf.local

zone "example.inc" {
        type master;
        file "/etc/bind/zones/example.inc.db";
};
zone "201.168.192.in-addr.arpa" {
        type master;
        file "/etc/bind/zones/rev.201.168.192.in-addr.arpa";
};

opciones.de.conf.con nombre

options {
        directory "/var/cache/bind";

        // If there is a firewall between you and nameservers you want
        // to talk to, you may need to fix the firewall to allow multiple
        // ports to talk.  See http://www.kb.cert.org/vuls/id/800113

        // If your ISP provided one or more IP addresses for stable
        // nameservers, you probably want to use them as forwarders.
        // Uncomment the following block, and insert the addresses replacing
        // the all-0's placeholder.

        forwarders {
                1.2.3.4; //IP of our external DNS provider
        };

        auth-nxdomain no;    # conform to RFC1035
        listen-on-v6 { any; };
};

ejemplo.inc.db

$TTL 86400
example.inc.      IN      SOA     ns1.ipower.com. admin.example.inc. (
                                                        2006081401
                                                        28800
                                                        3600
                                                        604800
                                                        38400
)
serv1                IN      A               192.168.201.223
serv2                IN      A               192.168.201.220
serv3         IN      A               192.168.201.219
ns1.ipower.com.      IN      A               1.2.3.4
ns2.ipower.com.      IN      A               1.2.3.5
@                    IN      NS              ns1.ipower.com.
@                    IN      NS              ns2.ipower.com.
svn                  IN      CNAME           serv1
docs                 IN      CNAME           serv2
jira                 IN      CNAME           serv3
confluence           IN      CNAME           serv3
fisheye              IN      CNAME           serv3

rev.201.168.192.in-addr.arpa

$TTL 86400
201.168.192.in-addr.arpa. IN SOA ns1.ipower.com. admin.example.inc. (
                        2006081401;
                        28800;
                        604800;
                        604800;
                        86400
)

223                    IN    PTR    serv1
@                      IN    NS     ns1.ipower.com.
@                      IN    NS     ns2.ipower.com.

nombrado.conf

include "/etc/bind/named.conf.options";
include "/etc/bind/named.conf.local";
include "/etc/bind/named.conf.default-zones";

Luego hice de nuestro DNS interno mi DNS preferido y los dos DNS externos fueron los siguientes en la fila. En su mayor parte, esto parece funcionar, puedo hacer ping a svn.example.inc y se resuelve en la IP correcta, también puedo hacer ping a google.com y tampoco resuelve ningún problema. Entonces todo parece bien.

Sin embargo, periódicamente (al menos un par de veces al día), pierdo la capacidad de hacer ping a svn.example.inc (y a todos los demás definidos en el DNS interno). Lo que parece solucionar el problema temporalmente es realizar un cambio en el adaptador de red de la máquina cliente y luego revertir el cambio. Luego funciona por un tiempo pero siempre volverá a fallar.

Información del sistema

DNS interno

Distributor ID: Debian
Description:    Debian GNU/Linux 6.0.6 (squeeze)
Release:        6.0.6
Codename:       squeeze

Linux 2.6.32-5-686 i686

BIND 9.7.3

ordenador personal

OS Name:                   Microsoft Windows 7 Professional
OS Version:                6.1.7601 Service Pack 1 Build 7601
System Type:               x64-based PC

Network Card(s):           2 NIC(s) Installed.
                           [01]: Realtek PCIe GBE Family Controller
                                 Connection Name: WORK LAN
                                 DHCP Enabled:    No
                                 IP address(es)
                                 [01]: the.ipv4.address
                                 [02]: the:ipv6:address

Resultado de excavación + rastreo

; <<>> DiG 9.3.2 <<>> +trace
;; global options:  printcmd
.                       49341   IN      NS      h.root-servers.net.
.                       49341   IN      NS      k.root-servers.net.
.                       49341   IN      NS      i.root-servers.net.
.                       49341   IN      NS      g.root-servers.net.
.                       49341   IN      NS      a.root-servers.net.
.                       49341   IN      NS      e.root-servers.net.
.                       49341   IN      NS      f.root-servers.net.
.                       49341   IN      NS      d.root-servers.net.
.                       49341   IN      NS      j.root-servers.net.
.                       49341   IN      NS      c.root-servers.net.
.                       49341   IN      NS      b.root-servers.net.
.                       49341   IN      NS      l.root-servers.net.
.                       49341   IN      NS      m.root-servers.net.
;; Received 244 bytes from 192.168.201.223#53(192.168.201.223) in 3 ms

.                       518400  IN      NS      a.root-servers.net.
.                       518400  IN      NS      b.root-servers.net.
.                       518400  IN      NS      c.root-servers.net.
.                       518400  IN      NS      d.root-servers.net.
.                       518400  IN      NS      e.root-servers.net.
.                       518400  IN      NS      f.root-servers.net.
.                       518400  IN      NS      g.root-servers.net.
.                       518400  IN      NS      h.root-servers.net.
.                       518400  IN      NS      i.root-servers.net.
.                       518400  IN      NS      j.root-servers.net.
.                       518400  IN      NS      k.root-servers.net.
.                       518400  IN      NS      l.root-servers.net.
.                       518400  IN      NS      m.root-servers.net.
;; Received 492 bytes from 128.63.2.53#53(h.root-servers.net) in 478 ms

Registro del sistema durante el reinicio de bind9

root@DET4A:~# tail -f /var/log/syslog
Oct 22 14:51:49 DET4A named[17248]: zone 255.in-addr.arpa/IN: loaded serial 1
Oct 22 14:51:49 DET4A named[17248]: /etc/bind/zones/dsasystems.inc.db:12: ignoring out-of-zone data (ns1.ipower.com)
Oct 22 14:51:49 DET4A named[17248]: /etc/bind/zones/dsasystems.inc.db:13: ignoring out-of-zone data (ns2.ipower.com)
Oct 22 14:51:49 DET4A named[17248]: zone example.inc/IN: loaded serial 2006081401
Oct 22 14:51:49 DET4A named[17248]: zone localhost/IN: loaded serial 2
Oct 22 14:51:49 DET4A named[17248]: managed-keys-zone ./IN: loading from master file managed-keys.bind failed: file not found
Oct 22 14:51:49 DET4A named[17248]: managed-keys-zone ./IN: loaded serial 0
Oct 22 14:51:49 DET4A named[17248]: zone example.inc/IN: sending notifies (serial 2006081401)
Oct 22 14:51:49 DET4A named[17248]: zone 201.168.192.in-addr.arpa/IN: sending notifies (serial 2006081401)
Oct 22 14:51:49 DET4A named[17248]: running
Oct 22 14:56:51 DET4A named[17248]: received control channel command 'stop -p'
Oct 22 14:56:51 DET4A named[17248]: shutting down: flushing changes
Oct 22 14:56:51 DET4A named[17248]: stopping command channel on 127.0.0.1#953
Oct 22 14:56:51 DET4A named[17248]: stopping command channel on ::1#953
Oct 22 14:56:51 DET4A named[17248]: no longer listening on ::#53
Oct 22 14:56:51 DET4A named[17248]: no longer listening on 127.0.0.1#53
Oct 22 14:56:51 DET4A named[17248]: no longer listening on 192.168.201.223#53
Oct 22 14:56:51 DET4A named[17248]: exiting
Oct 22 14:56:52 DET4A named[17303]: starting BIND 9.7.3 -u bind
Oct 22 14:56:52 DET4A named[17303]: built with '--prefix=/usr' '--mandir=/usr/share/man' '--infodir=/usr/share/info' '--sysconfdir=/etc/bind' '--localstatedir=/var' '--enable-threads' '--enable-largefile' '--with-libtool' '--enable-shared' '--enable-static' '--with-openssl=/usr' '--with-gssapi=/usr' '--with-gnu-ld' '--with-dlz-postgres=no' '--with-dlz-mysql=no' '--with-dlz-bdb=yes' '--with-dlz-filesystem=yes' '--with-dlz-ldap=yes' '--with-dlz-stub=yes' '--with-geoip=/usr' '--enable-ipv6' 'CFLAGS=-fno-strict-aliasing -DDIG_SIGCHASE -O2' 'LDFLAGS=' 'CPPFLAGS='
Oct 22 14:56:52 DET4A named[17303]: adjusted limit on open files from 1024 to 1048576
Oct 22 14:56:52 DET4A named[17303]: found 2 CPUs, using 2 worker threads
Oct 22 14:56:52 DET4A named[17303]: using up to 4096 sockets
Oct 22 14:56:52 DET4A named[17303]: loading configuration from '/etc/bind/named.conf'
Oct 22 14:56:52 DET4A named[17303]: reading built-in trusted keys from file '/etc/bind/bind.keys'
Oct 22 14:56:52 DET4A named[17303]: using default UDP/IPv4 port range: [1024, 65535]
Oct 22 14:56:52 DET4A named[17303]: using default UDP/IPv6 port range: [1024, 65535]
Oct 22 14:56:52 DET4A named[17303]: listening on IPv6 interfaces, port 53
Oct 22 14:56:52 DET4A named[17303]: listening on IPv4 interface lo, 127.0.0.1#53
Oct 22 14:56:52 DET4A named[17303]: listening on IPv4 interface eth0, 192.168.201.223#53
Oct 22 14:56:52 DET4A named[17303]: generating session key for dynamic DNS
Oct 22 14:56:52 DET4A named[17303]: set up managed keys zone for view _default, file 'managed-keys.bind'
Oct 22 14:56:52 DET4A named[17303]: automatic empty zone: 254.169.IN-ADDR.ARPA
Oct 22 14:56:52 DET4A named[17303]: automatic empty zone: 2.0.192.IN-ADDR.ARPA
Oct 22 14:56:52 DET4A named[17303]: automatic empty zone: 100.51.198.IN-ADDR.ARPA
Oct 22 14:56:52 DET4A named[17303]: automatic empty zone: 113.0.203.IN-ADDR.ARPA
Oct 22 14:56:52 DET4A named[17303]: automatic empty zone: 255.255.255.255.IN-ADDR.ARPA
Oct 22 14:56:52 DET4A named[17303]: automatic empty zone: 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.IP6.ARPA
Oct 22 14:56:52 DET4A named[17303]: automatic empty zone: 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.IP6.ARPA
Oct 22 14:56:52 DET4A named[17303]: automatic empty zone: D.F.IP6.ARPA
Oct 22 14:56:52 DET4A named[17303]: automatic empty zone: 8.E.F.IP6.ARPA
Oct 22 14:56:52 DET4A named[17303]: automatic empty zone: 9.E.F.IP6.ARPA
Oct 22 14:56:52 DET4A named[17303]: automatic empty zone: A.E.F.IP6.ARPA
Oct 22 14:56:52 DET4A named[17303]: automatic empty zone: B.E.F.IP6.ARPA
Oct 22 14:56:52 DET4A named[17303]: automatic empty zone: 8.B.D.0.1.0.0.2.IP6.ARPA
Oct 22 14:56:52 DET4A named[17303]: command channel listening on 127.0.0.1#953
Oct 22 14:56:52 DET4A named[17303]: command channel listening on ::1#953
Oct 22 14:56:52 DET4A named[17303]: the working directory is not writable
Oct 22 14:56:52 DET4A named[17303]: zone 0.in-addr.arpa/IN: loaded serial 1
Oct 22 14:56:52 DET4A named[17303]: zone 127.in-addr.arpa/IN: loaded serial 1
Oct 22 14:56:52 DET4A named[17303]: zone 201.168.192.in-addr.arpa/IN: loaded serial 2006081401
Oct 22 14:56:52 DET4A named[17303]: zone 255.in-addr.arpa/IN: loaded serial 1
Oct 22 14:56:52 DET4A named[17303]: /etc/bind/zones/dsasystems.inc.db:12: ignoring out-of-zone data (ns1.ipower.com)
Oct 22 14:56:52 DET4A named[17303]: /etc/bind/zones/dsasystems.inc.db:13: ignoring out-of-zone data (ns2.ipower.com)
Oct 22 14:56:52 DET4A named[17303]: zone dsasystems.inc/IN: loaded serial 2006081401
Oct 22 14:56:52 DET4A named[17303]: zone localhost/IN: loaded serial 2
Oct 22 14:56:52 DET4A named[17303]: managed-keys-zone ./IN: loading from master file managed-keys.bind failed: file not found
Oct 22 14:56:52 DET4A named[17303]: managed-keys-zone ./IN: loaded serial 0
Oct 22 14:56:52 DET4A named[17303]: zone dsasystems.inc/IN: sending notifies (serial 2006081401)
Oct 22 14:56:52 DET4A named[17303]: running
Oct 22 14:56:52 DET4A named[17303]: zone 201.168.192.in-addr.arpa/IN: sending notifies (serial 2006081401)

resolver.conf en DNS

search example.inc
nameserver 209.253.113.18 //This is the IP of the external DNS provider

Para ser honesto, con respecto al archivo resolve.conf, no estoy seguro de qué tipo de papel desempeña en el lado DNS.

Respuesta1

Muchas gracias aherreropor finalmente proporcionar la respuesta a esta.

El problema parece deberse a que las prioridades del servidor DNS no se borran todo el tiempo. Parece que a veces no se utiliza el DNS preferido y, por tanto, no se puede resolver el enlace.

Esteenlaceen el sitio de soporte de Microsoft detalla el problema y también proporciona la solución.

La solución

  1. Abra el editor de registro en Windows - ingreseregediten la ventana de búsqueda en el menú inicio'=
  2. Navegar aHKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Dnscache\Parameters
  3. Agregar un nuevoREG_DWORDllamadoLímite de tiempo de prioridad del servidory asignar el valor0

Esto asegurará que las prioridades del servidor DNS se restablezcan antes de decidir qué DNS usar.

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