LinuxQuestions.org
Register a domain and help support LQ
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Newbie
User Name
Password
Linux - Newbie This Linux forum is for members that are new to Linux.
Just starting out and have a question? If it is not in the man pages or the how-to's this is the place!

Notices


Reply
  Search this Thread
Old 07-31-2013, 06:42 PM   #1
Altiris
Member
 
Registered: Mar 2013
Posts: 555

Rep: Reputation: Disabled
Can't ping CentOS Server


Im running centos 6.4, whenever I try to do "ping externalipaddress" nothing happens, internally it works. I try it on another computer and it says request timed out. I can ping another computer running windows server that is on the same router but not mine, I am guessing the CentOS firewall is blocking ping? Do I need to add a DNS record for my external ip? Is my external ip not correctly associated with this computer? How can I check whats wrong?
 
Old 07-31-2013, 06:48 PM   #2
Ser Olmy
Senior Member
 
Registered: Jan 2012
Distribution: Slackware
Posts: 2,412

Rep: Reputation: Disabled
I don't quite understand what the problem is. Are you saying you can't ping from the CentOS server, or that you can't ping the IP address of the CentOS server?

You're mentioning an external IP address. How is that related to your server?
 
Old 07-31-2013, 06:51 PM   #3
Altiris
Member
 
Registered: Mar 2013
Posts: 555

Original Poster
Rep: Reputation: Disabled
Sorry for not being clear. I can't ping the IP address of the CentOS server from any computer. The external IP is the server's external IP, thats how it is related, it is a static IP.
 
Old 07-31-2013, 06:53 PM   #4
Ser Olmy
Senior Member
 
Registered: Jan 2012
Distribution: Slackware
Posts: 2,412

Rep: Reputation: Disabled
OK, so the CentOS server has a public IP address on a separate network adapter?
 
Old 07-31-2013, 07:01 PM   #5
Altiris
Member
 
Registered: Mar 2013
Posts: 555

Original Poster
Rep: Reputation: Disabled
Quote:
Originally Posted by Ser Olmy View Post
OK, so the CentOS server has a public IP address on a separate network adapter?
Uh, I dont understand. It only has one network adapter, both the internal and external IP is on the same adapter...I have a Sonicwall firewall and I see that I still have some rules for another computer that I used to use to host (it used to use the same external IP that the centos server uses now), could there be a conflict?
 
Old 07-31-2013, 07:11 PM   #6
Ser Olmy
Senior Member
 
Registered: Jan 2012
Distribution: Slackware
Posts: 2,412

Rep: Reputation: Disabled
If you have a SonicWall firewall, isn't the public IP address assigned to the WAN interface of the firewall?

What do the following commands return when run on your CentOS server?
Code:
ifconfig -a

ip addr show
 
Old 07-31-2013, 07:19 PM   #7
Altiris
Member
 
Registered: Mar 2013
Posts: 555

Original Poster
Rep: Reputation: Disabled
Quote:
Originally Posted by Ser Olmy View Post
If you have a SonicWall firewall, isn't the public IP address assigned to the WAN interface of the firewall?

What do the following commands return when run on your CentOS server?
Code:
ifconfig -a

ip addr show
Yes thats true, originally the external IP address of the computer is assigned to the same IP of the firewall, however as soon as I create a NAT policy (the nat policy links the computers internal and external IP), it sets the external IP to whatever I set it to.

ifconfig -a output
Code:
eth0      Link encap:Ethernet  HWaddr D4:3D:7E:9B:7A:06  
          inet addr:192.168.12.137  Bcast:192.168.12.255  Mask:255.255.255.0
          inet6 addr: fe80::d63d:7eff:fe9b:7a06/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:4078786 errors:0 dropped:0 overruns:0 frame:0
          TX packets:576252 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:5809998576 (5.4 GiB)  TX bytes:78193084 (74.5 MiB)
ip addr show output
Code:
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether d4:3d:7e:9b:7a:06 brd ff:ff:ff:ff:ff:ff
    inet 192.168.12.137/24 brd 192.168.12.255 scope global eth0
    inet6 fe80::d63d:7eff:fe9b:7a06/64 scope link 
       valid_lft forever preferred_lft forever
(Note that I didnt paste any lo output as I thought it wasnt useful.
 
Old 07-31-2013, 07:38 PM   #8
Ser Olmy
Senior Member
 
Registered: Jan 2012
Distribution: Slackware
Posts: 2,412

Rep: Reputation: Disabled
As you can see, the server only has a single IP address, 192.168.12.137. This IP address is a "private" or "non-routable" IP address for use in private, closed networks like your own. The public IP address you're using to access the Internet (the one displayed if you visit a site like http://whatismyipaddress.com) belongs to the SonicWall.

If you want a service on the CentOS server to become available to outside users accessing the public IP address of the SonicWall, you need to tell the firewall in the router to perform "port forwarding" for the service in question.

You say there are rules in the firewall related to a computer you previously had on your network. You may be able to simply change the IP address in those rules, pointing it to your CentOS server instead.
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off



Similar Threads
Thread Thread Starter Forum Replies Last Post
ping to server does not work until i ping from the other direction. weird! jstilby Linux - Networking 1 10-26-2011 08:42 AM
centos - able to ping computer that is in a different network. Pl.help koshy Linux - Newbie 6 05-26-2011 01:58 AM
Can't Ping past gateway. Can ping server from outside ugolee Linux - Networking 11 05-02-2010 12:35 AM
Ping problem on CentOs 4.4 dipuasks Linux - Networking 9 04-06-2007 12:03 AM
windows 98 m/c ping to ip address of red hat server but fails to ping hostname ravilohot Linux - Networking 2 09-07-2004 05:57 AM


All times are GMT -5. The time now is 01:11 PM.

Main Menu
Advertisement
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration