General network question

[dsprous]

Greetings all:

I am a novice at networking so if this is obvious please forgive the post.

I have a new installation of FC4 on a computer that is within a firewall. I can ping every computer that is within the firewall fine. However, when I ping anything beyond the firewall, it returns a "Host Unreachable". It is able to resolve names:

> ping forums.fedoraforum.org
PING forums.fedoraforum.org (70.85.88.134) 56(84) bytes of data
From 192.168.0.45 icmp_seq=0 Destination Host Unreachable
...

If anyone could point me to a general process to fix this problem, I would be grateful.

-- Dennis

[kurzer]

It seems as if you set up the dns (domain name server) right because forums.fedoraforum.org was resolved right.
I guess you can ping your firewall, right?
So you have to configure your firewall that it passes through your requests, like a router. If it is a Linux firewall read
man iptables
and then (as I didn't understand much of that manpage) search this forum and the internet for iptables, masquerade, etc.

[Jman]

You probably need a gateway setup. This would be your broadband router that connects you to the network. Set it up with the System Settings > Network configuration tool. Edit your network device and enter the gateway IP.

[w5set]

If it's your lan, then I would figure you could set the firewall so it will pass icmp traffic--if it's not your own personal equipment (business lan)--then ask the admin if he will do this.
But why??? If the internet is accessable and working, why bother?
Gateway for the firewall is already setup it seems--it's working. Your computer found the gateway and nameserver because it returned the "dotted quad" IP address for fedoraforum.
Again--why is it necesaary? ICMP traffic sometimes is rejected both ways by a firewall (in-out) for security reasons--if I drop an ICMP incoming packet--I don't seem to be present to the internet in that form of searching. (there are many other ways though to find whether someone is present on the internet)
Many colleges and universities are starting to block icmp in and out traffic--just to deter the local computer networking genuises (students) from hanging themselves if nothing else.