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Can not ping network's live IP from whithin the network

Saurabh Pillai
Ranch Hand

Joined: Sep 12, 2008
Posts: 507
Is it not possible or some settings need to be changed?

I need this in order to check port forwarding.

Thank you
Peter Johnson
author
Bartender

Joined: May 14, 2008
Posts: 5823
    
    7

I don't understand your question. You should be able to ping via IP address any computer's IP address (unless the firewall prevents access to the ping port). Perhaps if you gave an example that would help.


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Saurabh Pillai
Ranch Hand

Joined: Sep 12, 2008
Posts: 507
As you can see in the attached image, production,database and staging servers are under one network. Production and DB servers have LIVE ip address that I can ping directly when I am outside their network. Staging does not have live IP address, so in order to access it from outside,say using PuTTY, I have to set port forwarding, right? Now, the other day, I was on production server and tried to ping live IP address of database server and it gave me this error,

[root@server ~]# ping x.x.x.x
PING x.x.x.x (x.x.x.x) 56(84) bytes of data.
From y.y.y.y: icmp_seq=1 Redirect Host(New nexthop: y.y.y.y)
From y.y.y.y icmp_seq=1 Destination Host Unreachable
From y.y.y.y icmp_seq=2 Destination Host Unreachable
From y.y.y.y icmp_seq=3 Destination Host Unreachable
...

I can ping the same IP address once I am outside of that network. I can also ping their local IP addresses.



[Thumbnail for Network.jpg]

William P O'Sullivan
Ranch Hand

Joined: Mar 28, 2012
Posts: 859

As Peter said, there are many factors here to consider.

Are routing tables enforced?

Are these windows (basic tcp/ip services such as ping installed), or linux etc.?

WP
Saurabh Pillai
Ranch Hand

Joined: Sep 12, 2008
Posts: 507
William P O'Sullivan wrote:Are routing tables enforced?


How can I verify this?

William P O'Sullivan wrote:Are these windows (basic tcp/ip services such as ping installed), or linux etc.?

They CentOS 5.5 (Linux). I can ping these machine from OUTSIDE the network, so I think PING utility has to be installed, no?

PS : - I am noob in linux and networking :-)
William P O'Sullivan
Ranch Hand

Joined: Mar 28, 2012
Posts: 859

Every service/port can be closed via firewalls, router/switch setups etc.

Your situation seems complex. I would try to map out (as you did with the diagram)
what services, ports, daemons etc. are running.

This is not a programming issue IMHO, but infrastructure.

WP
Peter Johnson
author
Bartender

Joined: May 14, 2008
Posts: 5823
    
    7

Try running ifconfig on each machine. That should tell you all of the IP addresses configured for the machine. You should notice that there are two sets of IP addresses, one for the public network (what you are calling the LIVE IP), and the other for the internal network. That is for a basic setup. But network admins can play all kinds of games with network topology, so you might have to find one of them, tie him (or her) down, and ask your questions.
 
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