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D-link dsl-504 cant block ports

 
 
rello
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      06-16-2004
hi we have a network of two sharing a dsl connection
port scans from grc and sygate both reveal many ports open..in fact
only about 6 are stealthed.......the strange thing is if we install a
software firewall,,,[tried kerio and zonealarm] we get exactly the
same result...i have used kerio b4 on a small network with no hardware
and found it to be pretty excellent...i can only assume the the router
is to blame....it is supposed to have a firewall that obviously is not
working properly...
any advice on securing this network gratefully received
relloman
 
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Todd Shillam
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      06-16-2004
Rello,

Some (not all) routers do have built-in firewalls; however, you don't want to close the ports to any 'active' applications. If you're running applications that require certain ports, those ports must be open; otherwise, the program will not work correctly.

When you use ZoneAlarm, you authorize a program to communicate with the Internet. When you authorize a program to access the Internet, ZoneAlarm configures (opens) the necessary ports for that application.

Like you mentioned, the router may also have some open ports. Check your 'port-forwarding' settings if available. If your router doesn't have a built-in firewall, then you may be exposed to Internet instrusions. By the way...what are you using to scan your ports? Are you scanning the router, or your machine(s)?

Best regards,

Todd Shillam
Information Technology Consultant
Shillam Technology
WWW: http://shillamtechnology.point2this.com

"rello" <(E-Mail Removed)> wrote in message news:40d0cfe7.1187497@news-server...
hi we have a network of two sharing a dsl connection
port scans from grc and sygate both reveal many ports open..in fact
only about 6 are stealthed.......the strange thing is if we install a
software firewall,,,[tried kerio and zonealarm] we get exactly the
same result...i have used kerio b4 on a small network with no hardware
and found it to be pretty excellent...i can only assume the the router
is to blame....it is supposed to have a firewall that obviously is not
working properly...
any advice on securing this network gratefully received
relloman
 
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Andrew
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      06-17-2004
6/16/2004 7:03:16 PM

rello <(E-Mail Removed)> wrote in message

<40d0cfe7.1187497@news-server>



> hi we have a network of two sharing a dsl connection


> port scans from grc and sygate both reveal many ports open..in fact


> only about 6 are stealthed.......the strange thing is if we install

a

> software firewall,,,[tried kerio and zonealarm] we get exactly the


> same result...i have used kerio b4 on a small network with no

hardware

> and found it to be pretty excellent...i can only assume the the

router

> is to blame....it is supposed to have a firewall that obviously is

not

> working properly...


> any advice on securing this network gratefully received


> relloman




As Todd pointed out, any port forwarding or servers/share programs
running (that would show up as open on the software firewall)? ZA is
set to what security level? What do the scanners say if you leave
your SW firewall in place and remove your router (or is that what you
meant above, I presumed in line with router and FW)?

Big one... Have you updated the firmaware? My linky use to have a
similar issue, and it was tied to that version of the firmware....
--
Composed with Newz Crawler 1.7 http://www.newzcrawler.com/
 
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patricksoltani
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      06-17-2004
rello wrote:

> hi we have a network of two sharing a dsl connection
> port scans from grc and sygate both reveal many ports open.


which ones are open?
Have you enabled NAT, DHCP, etc on the router?
What else did you configure or did not configure on this DSL router?


..in fact
> only about 6 are stealthed.


Don't know what you mean by "stealthed" :-/.

.......the strange thing is if we install a
> software firewall,,,[tried kerio and zonealarm] we get exactly the
> same result...


It is understandable since the router sits in front of your machines,
thus putting firewall software on the machines does not change the equation.

i have used kerio b4 on a small network with no hardware
> and found it to be pretty excellent...i can only assume the the router
> is to blame....


Yup.

it is supposed to have a firewall that obviously is not
> working properly...
> any advice on securing this network gratefully received
> relloman


The result of portscan will tell you what is your next step. If you
follow the basic configure on these devices, then normally NAT is
enabled, so is dhcp and of course simple routing.
The outbound traffic should have no problem returning in this
configuration and no access from outside should be provided to the machine.

Regards,
Patrick Soltani.


 
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Hairy One Kenobi
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      06-17-2004
"rello" <(E-Mail Removed)> wrote in message
news:40d0cfe7.1187497@news-server...
> hi we have a network of two sharing a dsl connection
> port scans from grc and sygate both reveal many ports open..in fact
> only about 6 are stealthed.......the strange thing is if we install a
> software firewall,,,[tried kerio and zonealarm] we get exactly the
> same result...i have used kerio b4 on a small network with no hardware
> and found it to be pretty excellent...i can only assume the the router
> is to blame....it is supposed to have a firewall that obviously is not
> working properly...
> any advice on securing this network gratefully received


1. Turn off the DMZ function (note - this is just a Wild Ass Guess)

2. See if there is more up-to-date firmware available

HTH

--

Hairy One Kenobi

Disclaimer: the opinions expressed in this opinion do not necessarily
reflect the opinions of the highly-opinionated person expressing the opinion
in the first place. So there!


 
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rello
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      06-17-2004
On Thu, 17 Jun 2004 10:23:31 +0100, "Hairy One Kenobi"
<abuse@[127.0.0.1]> wrote:

>"rello" <(E-Mail Removed)> wrote in message
>news:40d0cfe7.1187497@news-server...
>> hi we have a network of two sharing a dsl connection
>> port scans from grc and sygate both reveal many ports open..in fact
>> only about 6 are stealthed.......the strange thing is if we install a
>> software firewall,,,[tried kerio and zonealarm] we get exactly the
>> same result...i have used kerio b4 on a small network with no hardware
>> and found it to be pretty excellent...i can only assume the the router
>> is to blame....it is supposed to have a firewall that obviously is not
>> working properly...
>> any advice on securing this network gratefully received

>
>1. Turn off the DMZ function (note - this is just a Wild Ass Guess)
>
>2. See if there is more up-to-date firmware available
>
>HTH

thanks all,
i tried the sw firewalls behind the router
will look at the firmware upgrade and the settings suggested
tnx
relloman
 
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