Network problems

[Lucio M Nicolosi]

On Wed, Dec 22, 2010 at 5:14 PM, Bill Stanley <bstanle at wowway.com> wrote:

[snips]

> Thanks for the reply...
>
> 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?
> Although Linux has much fewer viruses than Windoze, I don't have any
> illusions that they exist.  Although I am very careful about security,
> maybe one escaped my notice.  (I hope not.)
>
> 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.
>

Bill,

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.

Perhaps you could install ssh on both computers and check if a an ssh
connection is possible.

Some resident programs like f.i. Ubuntu One and Skype, open ports like
those you observed, and I guess this is pretty standard, no serious
security concerns needed.

I guess that, in linux, most viri and malware need your close
involvement and specific permission to get installed. But it is just
my guess.

Lucio

-- 
L M Nicolosi, Eng.
Ubuntu AMD64
GNU-Linux Regist. User #481505 - http://counter.li.org/