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Host or domain name not found
https://forum.linode.com/viewtopic.php?f=11&t=10785		 Page 2 of 3
Author:  Main Street James [ Sat Jan 18, 2014 9:19 pm ]
Post subject:  Re: Host or domain name not found
I'm not sure which logs will have those errors. Try going to /var/log then do a dig and then sort by date.

BTW, did you recently turn on IP6?
Author:  vincenzo [ Sat Jan 18, 2014 9:20 pm ]
Post subject:  Re: Host or domain name not found
Now check the log, but I have not turned on ipv6
Author:  Main Street James [ Sat Jan 18, 2014 9:24 pm ]
Post subject:  Re: Host or domain name not found
I'm not a networking guy so I'm not sure how much more help I can provide. Have you tried a Debian forum?
Author:  vincenzo [ Sat Jan 18, 2014 9:25 pm ]
Post subject:  Re: Host or domain name not found
Yes I have searched around, but I can not solve.
Author:  imMute [ Sat Jan 18, 2014 9:29 pm ]
Post subject:  Re: Host or domain name not found
Based on what you said the output of "dig gmail.com mx" was, you seem to have network issues, at least issues connecting to the DNS servers listed in /etc/resolv.conf

Please paste the output of
Code:
iptables-save
,
Code:
ip addr
, and
Code:
ip route show table all
.
Author:  vincenzo [ Sat Jan 18, 2014 9:35 pm ]
Post subject:  Re: Host or domain name not found
iptables-save:
Code:
:OUTPUT ACCEPT [324844:23039433]
:POSTROUTING ACCEPT [324844:23039433]                                                                 
COMMIT                                                                                                
# Completed on Sun Jan 19 02:31:21 2014                                                               
# Generated by iptables-save v1.4.2 on Sun Jan 19 02:31:21 2014                                       
*mangle                                                                                               
:PREROUTING ACCEPT [2354424:284655383]                                                                
:INPUT ACCEPT [2354343:284651291]                                                                     
:FORWARD ACCEPT [0:0]                                                                                 
:OUTPUT ACCEPT [2855189:2701890942]                                                                   
:POSTROUTING ACCEPT [2855189:2701890942]                                                              
COMMIT                                                                                                
# Completed on Sun Jan 19 02:31:21 2014                                                               
# Generated by iptables-save v1.4.2 on Sun Jan 19 02:31:21 2014                                       
*filter                                                                                               
:INPUT ACCEPT [2354343:284651291]                                                                     
:FORWARD ACCEPT [0:0]                                                                                 
:OUTPUT ACCEPT [2855189:2701890942]                                                                   
:fail2ban-ssh - [0:0]                                                                                 
-A INPUT -p tcp -m multiport --dports 22 -j fail2ban-ssh                                              
-A fail2ban-ssh -j RETURN                                                                             
COMMIT                                                                                                
# Completed on Sun Jan 19 02:31:21 2014


ip addr:
Code:
3: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether fe:fd:b2:4f:9b:f9 brd ff:ff:ff:ff:ff:ff
    inet 178.79.155.249/24 brd 178.79.155.255 scope global eth0                                       
       valid_lft forever preferred_lft forever                                                        
    inet6 fe80::fcfd:b2ff:fe4f:9bf9/64 scope link                                                     
       valid_lft forever preferred_lft forever                                                        
4: teql0: <NOARP> mtu 1500 qdisc noop state DOWN qlen 100                                             
    link/void                                                                                         
5: tunl0: <NOARP> mtu 0 qdisc noop state DOWN                                                         
    link/ipip 0.0.0.0 brd 0.0.0.0                                                                     
6: gre0: <NOARP> mtu 1476 qdisc noop state DOWN                                                       
    link/gre 0.0.0.0 brd 0.0.0.0                                                                      
7: gretap0: <BROADCAST,MULTICAST> mtu 1476 qdisc noop state DOWN qlen 1000                            
    link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff                                                
8: ip_vti0@NONE: <NOARP> mtu 1500 qdisc noop state DOWN                                               
    link/ipip 0.0.0.0 brd 0.0.0.0                                                                     
9: sit0: <NOARP> mtu 1480 qdisc noop state DOWN                                                       
    link/sit 0.0.0.0 brd 0.0.0.0                                                                      
10: ip6tnl0: <NOARP> mtu 1452 qdisc noop state DOWN                                                   
    link/tunnel6 :: brd ::                                                                            
11: ip6gre0: <NOARP> mtu 1448 qdisc noop state DOWN                                                   
    link/[823] 00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00 brd 00:00:00:00:00:00:00:00:00:00:00:00
:00:00:00:00


ip route show table all:
Code:
9: sit0: <NOARP> mtu 1480 qdisc noop state DOWN
    link/sit 0.0.0.0 brd 0.0.0.0                                                                      
10: ip6tnl0: <NOARP> mtu 1452 qdisc noop state DOWN                                                   
    link/tunnel6 :: brd ::                                                                            
11: ip6gre0: <NOARP> mtu 1448 qdisc noop state DOWN                                                   
    link/[823] 00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00 brd 00:00:00:00:00:00:00:00:00:00:00:00
:00:00:00:00                                                                                          
server1:~# ip route show table all                                                                    
default via 178.79.155.1 dev eth0                                                                     
178.79.155.0/24 dev eth0  proto kernel  scope link  src 178.79.155.249                                
broadcast 127.0.0.0 dev lo  table local  proto kernel  scope link  src 127.0.0.1                      
local 127.0.0.0/8 dev lo  table local  proto kernel  scope host  src 127.0.0.1                        
local 127.0.0.1 dev lo  table local  proto kernel  scope host  src 127.0.0.1                          
broadcast 127.255.255.255 dev lo  table local  proto kernel  scope link  src 127.0.0.1                
broadcast 178.79.155.0 dev eth0  table local  proto kernel  scope link  src 178.79.155.249            
local 178.79.155.249 dev eth0  table local  proto kernel  scope host  src 178.79.155.249              
broadcast 178.79.155.255 dev eth0  table local  proto kernel  scope link  src 178.79.155.249          
fe80::/64 dev eth0  proto kernel  metric 256                                                          
unreachable default dev lo  table unspec  proto kernel  metric -1  error -101                         
local ::1 dev lo  table local  proto none  metric 0                                                   
local fe80::fcfd:b2ff:fe4f:9bf9 dev lo  table local  proto none  metric 0                             
ff00::/8 dev eth0  table local  metric 256                                                            
unreachable default dev lo  table unspec  proto kernel  metric -1  error -101
Author:  imMute [ Sat Jan 18, 2014 9:39 pm ]
Post subject:  Re: Host or domain name not found
Firewall is fine. Network interface UP and route table looks fine.

Could you paste the output of
Code:
dig gmail.com MX
?
Author:  vincenzo [ Sat Jan 18, 2014 9:42 pm ]
Post subject:  Re: Host or domain name not found
Result:

; <<>> DiG 9.6-ESV-R4 <<>> gmail.com MX
;; global options: +cmd
;; connection timed out; no servers could be reached
Author:  imMute [ Sat Jan 18, 2014 9:44 pm ]
Post subject:  Re: Host or domain name not found
Okay, now try
Code:
dig @109.74.192.20 gmail.com MX
and if that fails
Code:
traceroute 109.74.192.20
Author:  vincenzo [ Sat Jan 18, 2014 9:47 pm ]
Post subject:  Re: Host or domain name not found
dig @109.74.192.20 gmail.com MX:

Code:

; <<>> DiG 9.6-ESV-R4 <<>> @109.74.192.20 gmail.com MX
; (1 server found)
;; global options: +cmd
;; connection timed out; no servers could be reached



traceroute 109.74.192.20:
Code:

traceroute to 109.74.192.20 (109.74.192.20), 30 hops max, 40 byte packets
 1  * * *
...
30  * * *
Author:  imMute [ Sat Jan 18, 2014 10:04 pm ]
Post subject:  Re: Host or domain name not found
It appears you're connecting to the Linode using LiSH instead of regular SSH. Are you unable to connect to it via SSH? Are you able to connect to other services running on the Linode?

That and the fact that dig can't connect to another Linode server to resolve domain names makes me think your networking is massively hosed. Are you able to
Code:
ping 178.79.155.1
?
Author:  vonskippy [ Sat Jan 18, 2014 10:05 pm ]
Post subject:  Re: Host or domain name not found
You need to start with the basics.

If you're not using IPv6, then remove it.

Can you ping 74.125.225.181?
Can you ping http://www.gmail.com?

If you can the first but not the second, then your name resolution is fubar'd.

Remove everything from your /etc/resolv.conf and just put in:
nameserver 8.8.8.8
nameserver 8.8.4.4

Then try ping http://www.gmail.com

If that doesn't work, it's a real puzzle, and I'd start to think your system had been compromised?

It would also help if you show the COMMAND and the RESULTS in your code snips, dumber things have happened when all parties ASSUME that the command is being entered correctly.
Author:  vincenzo [ Sat Jan 18, 2014 10:08 pm ]
Post subject:  Re: Host or domain name not found
I can connect with putty via ssh, but if I try to access ftp with root gives me connection timeout.

Result ping:
Code:
PING 178.79.155.1 (178.79.155.1) 56(84) bytes of data.
64 bytes from 178.79.155.1: icmp_seq=1 ttl=255 time=1.08 ms
...
64 bytes from 178.79.155.1: icmp_seq=22 ttl=255 time=0.958 ms

^C
--- 178.79.155.1 ping statistics ---
47 packets transmitted, 47 received, 0% packet loss, time 46058ms
rtt min/avg/max/mdev = 0.846/1.734/12.741/2.256 ms
Author:  vincenzo [ Sat Jan 18, 2014 10:16 pm ]
Post subject:  Re: Host or domain name not found
Result ping 74.125.225.181:

Code:
PING 74.125.225.181 (74.125.225.181) 56(84) bytes of data.
64 bytes from 74.125.225.181: icmp_seq=1 ttl=52 time=114 ms
64 bytes from 74.125.225.181: icmp_seq=2 ttl=52 time=114 ms
64 bytes from 74.125.225.181: icmp_seq=3 ttl=52 time=113 ms
64 bytes from 74.125.225.181: icmp_seq=4 ttl=52 time=113 ms
64 bytes from 74.125.225.181: icmp_seq=5 ttl=52 time=113 ms
64 bytes from 74.125.225.181: icmp_seq=6 ttl=52 time=114 ms
64 bytes from 74.125.225.181: icmp_seq=7 ttl=52 time=113 ms
64 bytes from 74.125.225.181: icmp_seq=8 ttl=52 time=114 ms
64 bytes from 74.125.225.181: icmp_seq=9 ttl=52 time=114 ms
64 bytes from 74.125.225.181: icmp_seq=10 ttl=52 time=114 ms
64 bytes from 74.125.225.181: icmp_seq=11 ttl=52 time=113 ms
64 bytes from 74.125.225.181: icmp_seq=12 ttl=52 time=113 ms
64 bytes from 74.125.225.181: icmp_seq=13 ttl=52 time=114 ms
64 bytes from 74.125.225.181: icmp_seq=14 ttl=52 time=114 ms
64 bytes from 74.125.225.181: icmp_seq=15 ttl=52 time=114 ms
64 bytes from 74.125.225.181: icmp_seq=16 ttl=52 time=113 ms
64 bytes from 74.125.225.181: icmp_seq=17 ttl=52 time=113 ms
64 bytes from 74.125.225.181: icmp_seq=18 ttl=52 time=113 ms
64 bytes from 74.125.225.181: icmp_seq=19 ttl=52 time=113 ms
64 bytes from 74.125.225.181: icmp_seq=20 ttl=52 time=113 ms
64 bytes from 74.125.225.181: icmp_seq=21 ttl=52 time=114 ms
64 bytes from 74.125.225.181: icmp_seq=22 ttl=52 time=113 ms
64 bytes from 74.125.225.181: icmp_seq=23 ttl=52 time=113 ms
64 bytes from 74.125.225.181: icmp_seq=24 ttl=52 time=113 ms
64 bytes from 74.125.225.181: icmp_seq=25 ttl=52 time=114 ms
64 bytes from 74.125.225.181: icmp_seq=26 ttl=52 time=113 ms
64 bytes from 74.125.225.181: icmp_seq=27 ttl=52 time=116 ms
64 bytes from 74.125.225.181: icmp_seq=28 ttl=52 time=113 ms
64 bytes from 74.125.225.181: icmp_seq=29 ttl=52 time=114 ms
64 bytes from 74.125.225.181: icmp_seq=30 ttl=52 time=114 ms
64 bytes from 74.125.225.181: icmp_seq=31 ttl=52 time=113 ms
64 bytes from 74.125.225.181: icmp_seq=32 ttl=52 time=115 ms
64 bytes from 74.125.225.181: icmp_seq=33 ttl=52 time=113 ms
64 bytes from 74.125.225.181: icmp_seq=34 ttl=52 time=114 ms
64 bytes from 74.125.225.181: icmp_seq=35 ttl=52 time=114 ms
64 bytes from 74.125.225.181: icmp_seq=36 ttl=52 time=114 ms
64 bytes from 74.125.225.181: icmp_seq=37 ttl=52 time=113 ms
64 bytes from 74.125.225.181: icmp_seq=38 ttl=52 time=114 ms
64 bytes from 74.125.225.181: icmp_seq=39 ttl=52 time=113 ms
64 bytes from 74.125.225.181: icmp_seq=40 ttl=52 time=113 ms
64 bytes from 74.125.225.181: icmp_seq=41 ttl=52 time=114 ms
64 bytes from 74.125.225.181: icmp_seq=42 ttl=52 time=114 ms
64 bytes from 74.125.225.181: icmp_seq=43 ttl=52 time=113 ms
^C
--- 74.125.225.181 ping statistics ---
43 packets transmitted, 43 received, 0% packet loss, time 42068ms
rtt min/avg/max/mdev = 113.189/114.004/116.166/0.842 ms



Ping http://www.gmail.com:
Code:
ping: unknown host http://www.gmail.com


About ten days ago, telling me that my linode server was receiving a dos attack, but I took countermeasures almost immediately by blocking the root user. Ill problem was solved almost immediately.

Now I try to change the resolv.conf and I'll let you know.
Author:  vincenzo [ Sat Jan 18, 2014 10:22 pm ]
Post subject:  Re: Host or domain name not found
I changed the file /etc/resolv.conf like this:

Code:
nameserver 8.8.8.8
nameserver 8.8.4.4


I did the ping http://www.google.com and I get this:

ping: unknown host http://www.gmail.com

I'm sorry, I can not understand what you need when you say this:
Quote:
It would also help if you show the COMMAND and the RESULTS in your code snips, dumber things have happened when all parties ASSUME that the command is being entered correctly.
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