diff --git a/sources/tech/How to set up a secondary DNS server in CentOS.md b/sources/tech/How to set up a secondary DNS server in CentOS.md index 81bef24e31..2c511b4d2b 100644 --- a/sources/tech/How to set up a secondary DNS server in CentOS.md +++ b/sources/tech/How to set up a secondary DNS server in CentOS.md @@ -1,53 +1,71 @@ [zzlyzq translating] +在CentOS中如何创建辅DNS服务器 How to set up a secondary DNS server in CentOS ================================================================================ In the [previous tutorial][1], we created a primary DNS server (ns1) for a test domain example.tst. In this tutorial, we will create a secondary DNS server (ns2) for the same domain by using bind package on CentOS. +在[前边的教程][1]，我们为一个测试域exmample.tst创建了一个主要DNS服务器（ns1）。在这边教程中，我们会使用bind包在CentOS中未相同的域创建一个辅DNS服务器（ns2）。 When it comes to setting up a secondary DNS server, the following factors should be kept in mind. +当创建一个辅DNS服务器的时候，下面的因素需要仔细考虑。 - You do NOT need to manually create forward and reverse zone files in the secondary DNS server. The zone files will be periodically synced from the primary DNS server automatically. -- Whenever any zone file is modified in the primary DNS server, the parameter 'serial' should be updated. The secondary DNS server will initiate synchronization (zone transfer) only if serial at the primary server has been changed. +- 在辅DNS服务器中，你不需要手动创建正向和反向区域文件。这些区域文件会定期从主DNS服务器上面同步。 +- Whenever any zone file is modified in the primary DNS server, the parameter 'serial' should be updated. The secondary DNS server will initiate synchronization (zone transfer) only if serial at the primary server has been changed. +- 当主DNS服务器上的任何区域文件被修改的时候，'serial'参数也应当被更新。只有当主服务器上面区域文件的serial被修改之后，辅DNS服务器才会进行同步。 We assume that the IP address of the secondary DNS server to be set up is 172.16.1.4. Let us start installing. +我们假设辅DNS服务器的IP地址是172.16.1.4。让我们来进行安装。 ### Setting up Hostnames ### +### 设置主机名 ### Just like the primary DNS server, the hostname of the secondary name server should be defined as FQDN properly. +就像主域名服务器一样，辅域名服务器的主机名也应当是一个合适的正式域名。 # vim /etc/sysconfig/network > HOSTNAME=ns2.example.tst Note that the hostname parameter specified in this file is used while the server is booting up. Therefore, the change does not take effect immediately. The following command can be used to change the hostname of a server immediately at run-time. +注意，在该文件中设置的主机名在服务器启动的时候会被使用。因此，如果你在系统启动之后修改，不会立刻生效。下面的命令可以用来在系统运行的时候立即修改。 # hostname ns2.example.tst Once set, hostname can be verified using the following command. +设置之后，可以用下面的命令来查看主机名称。 # hostname > ns2.example.tst Before proceeding to the next step, make sure that the hostname of all three servers are set properly. +在进行下面的步骤之前，确保所有三台服务器的主机名称已经被正确设置。 ### Installing Packages ### +### 安装软件包 ### Just like a [primary server][2], a secondary DNS server can be set up with or without chroot. Necessary packages can be easily installed using yum. +就像[主服务器][2]一样，配置一台辅域名服务器可以使用chroot或者不用。必须的软件包可以使用yum轻松安装。 Without chroot: +不使用 chroot: # yum install bind With chroot: +使用 chroot: # yum install bind-chroot ### Preparing Configuration File for Zone Transfers ### +### 为区域文件的传输准备配置文件 ### The DNS server powered by bind on CentOS will by default allow zone transfers for any requesting server. For security reasons, we need to configure the primary DNS server, such that it permits zone transfers to the secondary DNS server (172.16.1.4) only. +在CentOS中使用bind创建域名服务器后,默认设置允许所有的区域文件被任意服务器同步。安全起见，我们需要配置主域名服务器，只允许它允许辅域名服务器进行同步。 #### 1. Primary DNS Server #### + Without chroot: # vim /etc/named.conf @@ -55,7 +73,7 @@ Without chroot: With chroot: # vim /var/named/chroot/etc/named.conf - + ---------- zone "example.tst" IN { @@ -64,7 +82,7 @@ With chroot: allow-update { none; }; allow-transfer {172.16.1.4; }; ## NS2 is permitted ## }; - + zone "1.16.172.in-addr.arpa" IN { type master; file "rz-172-16-1"; ##the zone file hosted at NS1## @@ -85,13 +103,13 @@ With chroot: # cp /usr/share/doc/bind-9.8.2/sample/etc/named.rfc1912.zones /var/named/chroot/etc/named.conf After the sample configuration file is copied over, the following lines are added/modified. - + options { directory "/var/named"; forwarders {8.8.8.8; }; - + }; - + zone "example.tst" IN { type slave; ## NS2 role is defined ## file "example-fz"; ## the name of the zone file to be automatically created ## @@ -99,7 +117,7 @@ After the sample configuration file is copied over, the following lines are adde allow-transfer {172.16.1.3; }; ## NS1 is allowed for zone transfer when necessary ## masters {172.16.1.3; }; ## the master NS1 is defined ## }; - + zone "1.16.172.in-addr.arpa" IN { type slave; ## NS2 role is defined ## file "rz-172-16-1"; ## the name of the zone file to be automatically created ## @@ -137,22 +155,22 @@ We can use dig or nslookup to test DNS operations. We will be demonstrating the ---------- > server 172.16.1.4 - Default server: 172.16.1.4 - Address: 172.16.1.4#53 + Default server: 172.16.1.4 + Address: 172.16.1.4#53 > example.tst - Server: 172.16.1.4 - Address: 172.16.1.4#53 + Server: 172.16.1.4 + Address: 172.16.1.4#53 - Name: example.tst - Address: 172.16.1.3 + Name: example.tst + Address: 172.16.1.3 > set type=mx > example.tst - Server: 172.16.1.4 - Address: 172.16.1.4#53 + Server: 172.16.1.4 + Address: 172.16.1.4#53 - example.tst mail exchanger = 10 mail.example.tst. + example.tst mail exchanger = 10 mail.example.tst. > exit