search tot.co.th nameserver 192.168.1.1
Each of these records map a name to an IP address.
Example:
| Name | TTL | Type | IP |
| www.dnsmadeeasy.com. | 10800 | A | 192.168.1.2 |
| Name | TTL | Type | IP |
| www.dnsmadeeasy.com. | 10800 | A | 192.168.1.2 |
| www.dnsmadeeasy.com. | 10800 | A | 10.2.54.4 |
NOTE: It is important to know that only an A record can be made for your root host record. If you have a domain called example.com. and if you want an IP for example.com. then A record is the only valid solution for this. CNAME records are invalid.
| Wildcard Records give you the ability to map all (or a section) of the records in your domain to one IP. All Wildcard records are created with A records. If you create a record that is part of your domain (and inclusive of the wild card set) then only that record is directed to the other IP and everything else will goto the Wildcard record. Example:
The 'www' record would goto 10.2.54.4 but all of the other IPs would goto 192.168.1.2 All members can create Wildcard records for their domains. |
Load balancing / Round Robin allows you to distribute your server load evenly among multiple servers. This can all be handled in DNS Made Easy so you do not need to purchase expensive load balancers. The best part is that this service is "free" for all DNS Made Easy users!
All you have to do is create multiple A records with the same name but with a different IP / value.
Example:| Name | TTL | Type | IP |
| www.example.com. | 10800 | A | 192.168.1.2 |
| www.example.com. | 10800 | A | 10.2.54.4 |
50% of the time a user would go to 192.168.1.2 and 50% of the time the users would go to 10.2.54.4.
You can even split the traffic to more hosts. For example:
NOTE: There is generally a limit of (thirteen) 13 hosts that you can round robined (13 A records with the same name and different values) due to the limitations of the UDP packet which is what the DNS protocol generally runs over.
You can even combine this service with our DNS Failover service to remove a server from the loop if it is down!
CNAME Record (Canonical Name Record)
These are usually referred to as alias records since they usually map an alias to its canonical name. The name server does handle these queries differently from an A record. When a name server looks up a name and finds a CNAME record, it replaces the name with the canonical name and looks up the new name. This allows you to point multiple systems to one IP without specifically assigning an A record to each host name. If your IP was ever to change you would only have to change one A record.
Example:
| Name | TTL | Type | Data |
| www.dnsmadeeasy.com. | 10800 | A | 192.168.1.2 |
| ftp.dnsmadeeasy.com. | 10800 | CNAME | www.dnsmadeeasy.com. |
When the DNS server is queried for the ftp.dnsmadeeasy.com. system it realizes that it is an alias for www.dnsmadeeasy.com.. The system then returns the value of www.dnsmadeeasy.com.. which is 192.168.1.2. Whatever www.dnsmadeeasy.com. points to then so does ftp.dnsmadeeasy.com..
You can also use CNAME to point a record in one zone to a record in another zone. The following is valid:
| Name | Expire Time | TYPE | Data / Value (A Record) |
| www.dnsmadeeasy.com. | 10800 | CNAME | www.tiggee.com. |
NOTE: It is important that CNAME always are to the left hand side. You should never make an alias to an alias. Or you should never use MX or NS records with CNAME records. You can read more about NS and MX records later in this document.
NOTE: It is important to know that only an A record can be made for your root host record. If you have a domain called example.com. and if you want an IP for example.com. then A record is the only valid solution for this. CNAME records are invalid.
NS Record (Name Server Record)
These records indicate which name servers are authoritative for the zone.
Example:
| Name | TTL | Type | Data |
| ns.dnsmadeeasy.com. | 10800 | A | 192.168.10.12 |
| dnsmadeeasy.com. | 10800 | NS | ns.dnsmadeeasy.com |
You can also use NS records to assign the authoritative name server for a subdomain.
Example:
| Name | TTL | Type | Data (A Record) |
| sub.dnsmadeeasy.com. | 10800 | NS | ns1.dnsmadeeasy.com. |
Name servers will query ns1.dnsmadeeasy.com. for records in the sub.dnsmadeeasy.com. sub-domain
MX Record (Mail Exchange Record)
These records tell mail servers where to deliver mail. The name field of an MX record contains the host name which appears in the e-mail address, and the data field contains the hostname of the server to which the mail should be delivered. Two MX records that define the mail servers for the dnsmadeeasy.com domain might contain the following:
| Name | Expire Time | Type | MX level | Data (A Record) |
| dnsmadeeasy.com. | 10800 | MX | 10 | mail.dnsmadeeasy.com. |
| dnsmadeeasy.com. | 10800 | MX | 20 | backupmail.dnsmadeeasy.com. |
You can read all about the Redirection Service product here.
These are special records in that they are a combination of an A record and the use of an application server. There will be an A record pointing to our application servers which will redirect to the URL you specify.
HTTP Redirection Records allow you to map your FQDN to any URL of your choice.
For instance you can map. http://www.yourdomain.com
to
http://www2.yourdomain.com:9001/users/mypage.html
All users can create HTTP Redirection Records with any of the DNS Made Easy memberships.
These records are simply a list of strings, each less than 256 characters in length. TXT records can be used for anything you want.
Example Input for Domain Name: example.com
Name: mail
Data (TXT): This is the main mail server.
TTL: 1800 seconds
Result:
This will create a TXT record for the 'mail.example.com.' record and the description (text) of the record will be "This is the mail mail server.".
Pointer records are used to map a network interface (IP) to a host name. These are primarily used for reverse DNS.
Example Input for Domain Name: 1.168.192.in-addr.arpa
Name: 25
Data (PTR to): www.example.com.
TTL: 1800 seconds
Result:
This will create a reverse DNS entry for 192.168.1.25. The reverse DNS will be a pointer to 'www.example.com.'. This record will have a cache (TTL) of 30 minutes.
Of course 192.168.1.x is an internal network and would not be allowed in the DNS Made Easy system.
Thanks : dnsmadeeasy.com
การติดตั้ง DNS Server ด้วย Fedora Core 5
การติดตั้ง DNS Server เพื่อใช้งานในเครือข่ายองค์กร และเครือข่ายอินเตอร์เน็ต ....
การติดตั้ง DNS Server ด้วย Fedora Core 5
1. ตรวจสอบ BIND packet ด้วยคำสั่ง ดังตัวอย่างนี้
[ root@kk ~ ]# rpm -qa bind
bind-9.3.2-4.1
ในการทดลองนี้ ได้ติดตั้งโปรแกรม BIND ไว้แล้วคือ bind-9.3.2-4.1 ซึ่งเป็นเวอร์ชั่น 9.3.2-4.1
2. หากยังไม่ได้ติดตั้งโปรแกรม BIND สามารถดาวน์โหลดได้ที่ http://fedora.redhat.com/download/ ซึ่งต้องดาวน์โหลดเป็นไฟล์ rpm และเป็น Fedora Core 5 หรือสูงกว่า เมื่อดาวน์โหลดเสร็จแล้ว ทำการติดตั้งด้วยคำสั่ง ดังตัวอย่างนี้
[ root@kk ~ ]# rpm -ivh bind-9.3.2-4.1.rpm
3. เพิ่มชื่อโดเมน และกลุ่ม IP address ที่ต้องการ ลงไปในไฟล์ named.conf ดังตัวอย่างนี้
3.1 ใช้คำสั่ง vi เพื่อแก้ไขไฟล์ named.conf ดังตัวอย่างนี้
[ root@kk ~ ]# vi /etc/named.conf
3.2 กดปุ่ม insert หรือ กด i เพื่อแทรกและแก้ไขข้อความ
3.3 จากนั้นเพิ่มกลุ่มโดเมนและ กลุ่มไอพีแอดเดรส ดังตัวอย่างนี้
zone "kk.koogle.com" IN {
type master;
file "koogle.com.zone";
allow-update { none; };
};
zone "0.168.192.in-addr.arpa" IN {
type master;
file "192.168.0.zone";
allow-update { none; };
};
3.4 บันทึกไฟล์ named.conf ด้วยคำสั่ง ดังนี้
3.4.1 กดปุ่ม Esc
3.4.2 ตามด้วยเครื่องหมาย : และ wq!
3.5 สร้างไฟล์ ossthailand.com.zone และไฟล์ 192.168.0.zone ดังตัวอย่างนี้
3.5.1 เข้าไปยังไดเรคเทอรี่ /var/named/chroot/var/named ดังตัวอย่างนี้
[ root@kk ~ ]# cd /var/named/chroot/var/named/
3.5.2 สร้างไฟล์ koogle.com.zone โดยการก๊อบบี้จากไฟล์ localhost.zone ดังตัวอย่างนี้
[ root@kk named ]# cp localhost.zone koogle.com.zone
3.5.3 สร้างไฟล์ 192.168.0.zone โดยการก๊อบบี้จากไฟล์ localhost.zone ดังตัวอย่างนี้
[ root@kk named ]# cp localhost.zone 192.168.0.zone
3.6 แก้ไขไฟล์ koogle.com.zone ดังตัวอย่างนี้
$TTL 86400
@ IN SOA kk.koogle.com. root.kk.koogle.com (
2007022201 ; serial (d. adams)
3H ; refresh
15M ; retry
1W ; expiry
1D ) ; minimum
IN NS kk.koogle.com
koogle.com. IN NS kk.koogle.com
koogle.com. IN MX 5 mail.koogle.com
kk IN A 192.168.0.7
data IN A 192.168.0.1
www IN CNAME kk
ftp IN CNAME kk
3.7 แก้ไขไฟล์ 192.168.0.zone ดังตัวอย่างนี้
$TTL 86400
@ IN SOA kk.koogle.com. root.kk.koogle.com. (
2007022201 ; serial (d. adams)
3H ; refresh
15M ; retry
1W ; expiry
1D ) ; minimum
IN NS kk.koogle.com
1 IN PTR data.koogle.com
7 IN PTR kk.koogle.com
3.8 เปิดการใช้งานโปรแกรม BIND ด้วยคำสั่ง ดังตัวอย่างนี้
[ root@kk named ]# /etc/init.d/named restart
Stopping named: [ OK ]
Starting named: [ OK ]
3.9 ทดสอบ Forward mapping ด้วยโปรแกรม BIND โดยคำสั่ง dig ดังตัวอย่างนี้
[ root@kk ~ ]# dig kk.koogle.com
3.9.1 โดยแสดงรายการดังนี้
; <<>> DiG 9.3.2 <<>> kk.koogle.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 55458
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 0
;; QUESTION SECTION:
;kk.koogle.com. IN A
;; ANSWER SECTION:
kk.koogle.com. 86400 IN A 192.168.0.7
;; AUTHORITY SECTION:
koogle.com. 86400 IN NS kk.koogle.com.koogle.com.
;; Query time: 4 msec
;; SERVER: 192.168.0.7#53(192.168.0.7)
;; WHEN: Tue Mar 6 00:55:10 2007
;; MSG SIZE rcvd: 85
3.10 ทดสอบการทำงานโปรแกรม BIND ด้วยคำสั่ง nslookup ดังตัวอย่างนี้
[ root@kk ~ ]# nslookup
> kk.koogle.com <------- ใส่ชื่อโดเมนที่ต้องการตรวจสอบ
Server: 192.168.0.7
Address: 192.168.0.7#53
Name: cs.ossthailand.com
Address: 192.168.0.7
Thanks : kom.homelinux.org
