this afternoon my ISP (German Tele2) had activated my adsl account. They
gave me a Thomson Speedtouch 858i cable modem, but, something is
still not clear to me - maybe someone out has the same modem and knows if
the following things are "bugs" or "features".
- "Inside" my network I see several services running on the 858 - at least
one, let's say httpd is needed to configure the box. But:
$ nmap 192.168.1.254
Starting nmap 3.55 ( http://www.insecure.org/nmap/ ) at 2009-08-08 21:07 CEST
Interesting ports on 192.168.1.254:
(The 1654 ports scanned but not shown below are in state: filtered)
PORT STATE SERVICE
21/tcp open ftp
23/tcp open telnet
80/tcp open http
443/tcp open https
1723/tcp open pptp
8080/tcp closed http-proxy
Well, this is "inside", i.e. the "LAN" side, but, it seems to me, that all
these ports are visible from "outside" too. When I look which IP the
router has in the internet and I check this too, then the same ports are
open and accessible from outside. I consider this to be a security lack.
Is this normal?
Can access from outside be disabled as known from Cisco / Linksys?
- Furthermore, it seems to me that there's no way to manually start and
stop an internet connection. In the web based config menu you can start /
stop such a connection, but in my experience the modem establishes a
connection to the isp as soon as you plug in the dsl / telephone cable
into the 858.
Is this correct? Or can the 858 be configured in the way that a
connection is only set up when packets are passed to the 858i as the
default gateway, and after a certain timeout where nothing is transmitted,
the 858 stops the connection?
Thanks for any hint!
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