Network problems

[Tom H]

On Thu, Dec 23, 2010 at 3:45 AM, Lucio M Nicolosi <lmnicolosi at gmail.com> wrote:
> On Wed, Dec 22, 2010 at 5:14 PM, Bill Stanley <bstanle at wowway.com> wrote:
>>
>> I'm not certain if I am running two firewalls.  I assume I am because I
>> know I installed the gufw firewall on the computer that doesn't respond
>> to a ping.   I assume that Unbuntu installs a firewall by default.  If
>> so what is its name because I don't see any evidence of it.  This is the
>> first firewall I assume I have.  If there isn't one, then I have gufw only.
>>
>>  The strange thing is that I use the unaffected computer to do a port
>> scan (using the system/administration/network tools) and can get some
>> output back from the affected computer.
>>
>> The output of the port scan (from the unaffected computer) is...
>>
>> PORT  STATE  SERVICE
>> 111   open   sunprc
>> 2049  open   nfs
>> 40837 open   unknown
>> 45314 open   unknown
>> 50038 open   unknown
>>
>> When I do a port scan from the affected computer (of its port status i
>> get...
>>
>> Port   State   service
>> 111    open    sunprc
>> 2049   open    nfs
>> 40837  open    unknown
>> 45314  open    unknown
>> 50038  open    unknown
>> 52826  open    unknown
>>
>> I am somewhat concerned about the open ports with an unknown service.
>> Is there any way to get more information about those services?
>>
>> I notice that the unaffected computer can see the nfs service running on
>> the affected computer.  If I can see the nfs service running, what must
>> be done to share files using the nfs service.
>
> Although Ubuntu comes loaded with iptables, the core of any firewall,
> if no rules are set it "doesn't work". Gufw is just a graphic
> interface to iptables that enables easy handling of rules. I don't
> have Gufw installed right now and I can't remember if it can disable
> ping requests, (anyway, yours is probably unconfigured) like some DSL
> routers can do.

For the sake of future googlers: it isn't that the firewall doesn't
work on a default Ubuntu install, it's that there are no rules loaded;
gufw is a graphical front-end of ufw, which is itself a front-end
(with rule syntax similar to one of the BSDs) to iptables.

So having both ufw and gufw doesn't mean that you have two firewalls
installed and if you don't enable ufw (through the CLI or GUI) or
write or load some rules with iptables you won't have a firewall
running.

I don't see any samba ports in your output above. Are you sure that
you have samba running? How did you set up the shares?

For nfs, you must have it installed. To export a directory, you have
to edit "/etc/exports".