NTP
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Instalar e Configurar o NTP
Criado por: Alessandro C. M. Kuramoto
Data: 24/09/2008
Modificado em: 14/07/2010-20:44
v.20080924-0814
Palavras-chaves: NTP
Keywords: NTP
If you want to know something about this file, send an e-mail to me at the
sancmk@gmail.com or post a comment here (at the Word Press)
moshi kono fairu no koto wo shiteitakatara, boku ni email wo okutte kudasai,
matawa kono Word Press ni chuushaku mo shitte ii desu.
boku no email wa sancmk@gmail.com desu
Por favor, matenham o nome do autor deste arquivo.
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###############################################################################
# Conceitos:
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Portas:
udp/123
O daemon ntpd faz as consultas à partir dessa mesma porta UDP 123
|##########^ Conceitos #######################################################|
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# Servidor:
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SO: Debian 4.0 Etch
Servidor: NTP
Serviço: NTP
Instalação básica (modo texto).
—
CPU:
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 15
model name : Intel(R) Xeon(R) CPU X5365 @ 3.00GHz
stepping : 11
cpu MHz : 3000.292
cache size : 4096 KB
physical id : 0
siblings : 4
core id : 0
cpu cores : 4
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe lm constant_tsc pni monitor ds_cpl vmx est tm2 cx16 xtpr lahf_lm
bogomips : 6004.62
—–|
—
RAM (MB):
total used free shared buffers cached
Mem: 3291 285 3006 0 213 18
—–|
—
Swap:
Filesystem Tamanho Usado
/boot 100 MB 6.5 MB
/ 14 GB 234 MB
/tmp 1.8 GB 35 MB
/usr 14 GB 242 MB
/var 34 GB 163 MB
—–|
===============================================================================
Dados para referências/diferenciação: (Estudo de caso)
===============================================================================
- Squid com 2350 conexões (pode ter tido sinais SIGABRT)
- Em quatro processos tem-se 5298 Conexões
SIGABRT
(Fonte: http://pt.wikipedia.org/wiki/SIGABRT)
###############################################################################
# Instalando: #
###############################################################################
#### Debian 4.0
|
## Atualizando a lista de pacotes disponíveis
apt-get update
## Instalando o NTP
apt-get install ntp
|<<<<<<<<<<<<<< #### Instalando ####
===============================================================================
Instalando o NTP no Gentoo:
===============================================================================
|<<<<<<<<<<<<<< #### Instalando #### ==== Instalando o NTP no Gentoo ====
emerge ntp
## O arquivo de configuração /etc/ntp.conf do Gentoo vem vazio.
|==========^ Instalando o NTP no Gentoo ======================================|
|<<<<<<<<<<<<<< #### Instalando ####
#### OpenSuse 11.x:
|
Normalmente já vem instalado.
|##########^ Instalando ######################################################|
###############################################################################
# Configuração:
###############################################################################
===============================================================================
Configuração Geral – Explicação:
===============================================================================
_______________________________________________________________________________
Arquivo: /etc/ntp.conf (Permissão: -rw-r–r– 1 root root)
————————————————————
# /etc/ntp.conf, configuration for ntpd
# “memoria” para o escorregamento de frequencia do micro
# pode ser necessario criar esse arquivo manualmente com
# o comando touch ntp.drift
driftfile /var/lib/ntp/ntp.drift
# estatisticas do ntp que permitem verificar o historico
# de funcionamento e gerar graficos
statsdir /var/log/ntpstats/
statistics loopstats peerstats clockstats
filegen loopstats file loopstats type day enable
filegen peerstats file peerstats type day enable
filegen clockstats file clockstats type day enable
## iburst – Use fast initial sync mode (iburts)
## NTPs do Observatório Nacional:
server pcdsh05.on.br iburst
server ntp2.on.br
## Servidores publicos do projeto ntp.br:
server a.ntp.br
server b.ntp.br
#server c.ntp.br
# outros servidores
# server outro-servidor.dominio.br iburst
## Permite acesso completo da interface local
## Isso poderia ser restringido, mas afetaria algumas da funções
## administrativas
restrict 127.0.0.1
## Para proibir o acesso geral ao serviço de NTP:
# restrict default ignore
# Libera acesso da minha rede local ao server NTPD
restrict 10.10.10.0 mask 255.255.255.0 nomodify notrap
## Referência:
## http://www.cis.udel.edu/~mills/ntp/html/accopt.html
# configuracoes de restricao de acesso
restrict default kod notrap nomodify nopeer
## Às vezes será necessário criar o diretório e arquivos de logs:
## mkdir /var/log/ntp
## > /var/log/ntp/ntp.log
logconfig = all
logfile /var/log/ntp/ntp.log
|———-^ Arquivo: /etc/ntp.conf —————————————–|
## Permite que o ntp ajuste seu relógio mesmo que ele tenha um erro de tempo
## absurdamente alto (maior # que 16 min). O daemon ntp pode ser executado então:
## PS: para executar este comando é interessante que o daemon do NTP esteja
## parado
ntpd -q -g
ntpdc -c loopinfo
ntpq -c version
——————————————————————————-
Serviços:
###############################################################################
# Serviço NTP:
###############################################################################
## Iniciar o Serviço:
————————————
####
| No Debian
/etc/init.d/ntp start
#### No Ubuntu
|
/etc/init.d/ntp start
#### No OpenSuse
|
rcntp start
## Verificar o Status do Serviço:
ntpq -c peer
debian:~# ntpq -c pe
remote refid st t when poll reach delay offset jitter
==============================================================================
a.ntp.br 200.160.7.192 2 u 57 64 17 35.740 -43.823 29.334
b.ntp.br 200.160.7.186 2 u 112 64 16 19.832 -47.363 4.136
*c.ntp.br 200.160.7.192 2 u 18 64 37 7.940 -32.274 40.572
A primeira coluna apresenta os tally codes, que significam o seguinte:
* o system peer, par do sistema, ou principal fonte de sincronização
+ candidate, ou um relógio sobrevivente, indica que é uma boa fonte de sincronização e que está sendo utilizada no momento, juntamente com o par do sistema, para ajustar o relógio local
x falseticker, ou relógio falso, indica que não é uma boa fonte de sincronização, foi descartada já no algorítmo de seleção de relógios por discordar muito das outras fontes
refid – a referência (par do sistema) à qual o servidor de tempo remoto está sincronizado
st – o estrato da fonte de tempo
camadas ou estratos (em inglês: strata) numerados de 0 (zero) a 16 (dezesseis)
O estrato 0 (stratum 0) na verdade não faz parte da rede de servidores NTP, mas representa a referência primária de tempo, que é geralmente um receptor do Sistema de Posicionamento Global (GPS) ou um relógio atômico. O estrato 16 indica que um determinado servidor está inoperante.
poll – de quantos em quantos segundos essa fonte é consultada
reach -
um registrador de 8 bits que vai girando para a esquerda representado na forma octal, que mostra o resultado das últimas 8 consultas à fonte de tempo: 377 = 11.111.111 significa que todas as consultass foram bem sucedidas; outros número indicam falhas, por exemplo 375 = 11.111.101, indica que a penúltima consulta falhou
offset – deslocamento, ou quanto o relógio local tem de ser adiantado ou atrasado, em milisegundos, para ficar igual ao da fonte de tempo
Um deslocamento de -7 significa que o relógio local do Cliente deve ser atrasado 7 unidades de tempo para se igualar ao do Servidor.
Um deslocamento de 60005.8 significa que o relógio local do Cliente deve ser adiantado 60005.8 unidades de tempo (1 minuto) para se igualar ao do Servidor.
.STEP means ntp has needed to perform an instantaneous change to your system clock. When it does that it throws out all polling data and starts again, which is why the right-hand side is all 0′s.
.INIT Means it hasn’t successfully got a response back from any of those servers
——————————————————————————-
Erros:
suse:~ # ntpq -c pe
No association ID’s returned
|#############################################################################|
###############################################################################
# Gerenciando/Administrando:
###############################################################################
## Para ver a versão do servidor de NTP:
dpkg -S /usr/sbin/ntpd
dpkg -l | grep ntp
|#############################################################################|
###############################################################################
# Clientes de NTP:
###############################################################################
#### Configurar o cliente de NTP no OpenSuse:
yast
# Selecionar: Serviços de Rede > Configuração NTP
# em: Iniciar Daemon NTP Automaticamente, Marcar: Durante a Inicialização
# Selecionar: Configuração Avançada
# Selecionar: Adicionar
# Selecionar: Servidor
# Digite o nome do servidor de NTP, exemplo: a.ntp.br, selecione: Testar
# Marque a opção: Usar para Sincronização Inicial
# No OpenSuse o serviço será reiniciado automaticamente.
|##########^ Clientes de NTP #################################################|
###############################################################################
# Testando:
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## Comando utilizado para pesquisar servidores de NTP:
ntpq
> peers
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# Usando o ntpq:
###############################################################################
## Comando utilizado para fazer pesquisas em servidores de NTP:
ntpq
##
> host <ip>
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# Timezone (Fuso horário):
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http://www.timezoneconverter.com/cgi-bin/tzc.tzc
http://www.timeanddate.com/library/abbreviations/timezones/na/est.html
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# Mais:
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Verificar o tráfego na porta 123 (NTP)
tcpdump -nn host 200.189.40.8
19:59:31.698313 IP 10.7.3.224.123 > 200.189.40.8.123: NTPv4, Client, length 48
19:59:31.724805 IP 200.189.40.8.123 > 10.7.3.224.123: NTPv4, Server, length 48
——————————————————————————-
Outros comandos:
ntptrace
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# Troubleshooting:
###############################################################################
——————————————————————————-
## Erros conhecidos:
## Sintoma:
Ao executar o comando “ntpq -c peer” aparece a seguinte mensagem de erro:
localhost: timed out, nothing received
***Request timed out
## Causa:
>>>>>>> 1)
Este erro poder acontece na seguinte situação:
————————————————————-
A seguinte configuração existir com a palavra query:
restrict -4 default kod notrap nomodify nopeer noquery
e a linha abaixo estar comentada:
#restrict 127.0.0.1
————————————————————-
## Solução:
>>>>>>> 1)
Descomente a linha:
————————————————————-
#restrict 127.0.0.1
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|—————————————————————————–|
|##########^ Troubleshooting #################################################|
###############################################################################
# FAQ:
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Devo usar o ntpdate ou o ntpd?
Utilize o ntpd. Com ele consegue-se uma exatidão bem maior do que com o ntpdate.
Caso o relógio do seu computador esteja muito desajustado pode-se utilizar o ntpdate para ajustar o mesmo, antes de se rodar o daemon NTP. Mesmo nesse caso é preferível utilizar o ntpd com as opções -q e -g.
Não é recomendado utilizar-se o ntpdate no cron para manter o relógio do computador sincronizado. Utilize o daemon ntpd ao invés disso.
O ntpdate não é mais oficialmente suportado e deve ser retirado da distribuição em breve.
|##########^ FAQ #############################################################|
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# Referência:
###############################################################################
Referência Principal - http://www.ntp.br
http://www.catabits.com.br/blog/internet/mantenha-seu-relogio-em-dia
Event Messages and Status Words – Kiss Codes
http://www.cis.udel.edu/~mills/ntp/html/decode.html#kiss
NTP Server Monitor:
http://www.meinberg.de/english/sw/ntp.htm
NTP Network Appliances:
http://www.symmetricom.com/products/ntp-servers/ntp-network-appliances/
