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Phil
Asked: 2012-10-16 04:17:51 +0800 CST

I cannot telnet www.google.com 80 on my centos, why?

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On my centos I have a problem.

I cannot:

[root@server]# telnet www.google.com 80
telnet: www.google.com: Name or service not known
www.google.com: Unknown server error
[root@server]#

However I can dig google.com

[root@server]# dig www.google.com

; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.10.rc1.el6_3.3 <<>> www.google.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: REFUSED, id: 42872
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0
;; WARNING: recursion requested but not available

;; QUESTION SECTION:
;www.google.com.            IN  A

;; Query time: 0 msec
;; SERVER: 180.188.196.76#53(180.188.196.76)
;; WHEN: Mon Oct 15 20:15:21 2012
;; MSG SIZE  rcvd: 32

[root@server] #

My resolv.conf is

# Automatically generated by OnApp (2.3.2)
domain com
nameserver 180.188.196.76
nameserver 8.8.4.4
nameserver 8.8.8.8
centos

2 Answers

  1. Test other domain server (8.8.8.8 or 8.8.4.4 for example):

    dig @8.8.4.4 www.google.com

    If it could resolve the name, put it in the first place in your /etc/resolv.conf file, then try again the connection against port 80

    telnet www.google.com 80

    If this is still not working, then the problem is in your internet connection or network configuration, not in the DNS.

    • 1

  2. At first, it looks like server is refusing your requests:

    status: REFUSED

    But, if we take closer look, 0 (zero) msec is a very short time (if server isn't in your local network).

    Query time: 0 msec

;; SERVER: 180.188.196.76#53(180.188.196.76)

    Very hard to say what is the problem...

    Do you use some local caching for DNS?

    • Use your local or ISP's DNS, avoid using worldwide-free DNS servers - you might get some problems accessing CDN files.
    • Run BIND
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