DNS Issues
Bill Cavalieri
bcavalieri at gekl.net
Thu Jun 6 20:38:36 CDT 2002
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I use the RR Business cable modem service, its the Cisco UBR modem like
you said, I use a linksys cheapo nat/router behind the cisco router, and
have 6 computers on the internet that way. =20
-Bill
On Thu, 2002-06-06 at 15:17, Gerald Combs wrote:
On Thu, 6 Jun 2002, chuckx wrote:
=20
> > I suspect=20
> > they are using port monitoring to identify my first 48 bit NIC=20
> > address and when they see packets with another NIC address, they=20
> > refuse the DHCP request and I can't direct connect another system t=
o=20
> > my cable modem, thus I use NAT through the router to keep both my=20
> > systems up and on line. Pretty slick and easy to administer.
>=20
> What you described is just about right. Once you reach the maximum n=
umber
> of clients your modem is configured for, network traffic from additio=
nal
> hosts is not passed on to the cable network by the cable modem. Noti=
ce that
> your connection is not being actively monitored though. Your cable m=
odem is
> a just network bridge that is configured to pass network traffic for =
a
> limited number of hosts. The modem does keep track of the hosts conn=
ected
> to it via their MAC addresses.
=20
If RR is running Cisco uBR equipment (and I'm pretty sure they are),
they can block this at their end of the connection with the one-liner
'cable max-cpe 1':
=20
http://www.cisco.com/univercd/cc/td/doc/product/cable/bbccmref/bbcmts=
.htm#xtocid42
=20
The above link is an interesting read. They can mess with your cable
connection in all sorts of odd and interesting ways.
=20
=20
=20
=20
Bill Cavalieri
bcavalieri at gekl.net
VP IT Systems
816 880 0066
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I use the RR Business cable modem service, its the Cisco UBR modem like you=
said, I use a linksys cheapo nat/router behind the cisco router, and have =
6 computers on the internet that way. =20
<BR>
<BR>
-Bill
<BR>
<BR>
On Thu, 2002-06-06 at 15:17, Gerald Combs wrote:
<BLOCKQUOTE>
<PRE><FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I>On Thu, 6 Jun 2002, chuckx=
wrote:</FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I></FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I>> > I suspect </FONT></FO=
NT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I>> > they are using port m=
onitoring to identify my first 48 bit NIC </FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I>> > address and when they=
see packets with another NIC address, they </FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I>> > refuse the DHCP reque=
st and I can't direct connect another system to </FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I>> > my cable modem, thus =
I use NAT through the router to keep both my </FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I>> > systems up and on lin=
e. Pretty slick and easy to administer.</FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I>> </FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I>> What you described is just=
about right. Once you reach the maximum number</FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I>> of clients your modem is c=
onfigured for, network traffic from additional</FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I>> hosts is not passed on to =
the cable network by the cable modem. Notice that</FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I>> your connection is not bei=
ng actively monitored though. Your cable modem is</FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I>> a just network bridge that=
is configured to pass network traffic for a</FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I>> limited number of hosts. =
The modem does keep track of the hosts connected</FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I>> to it via their MAC addres=
ses.</FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I></FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I>If RR is running Cisco uBR equi=
pment (and I'm pretty sure they are),</FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I>they can block this at their en=
d of the connection with the one-liner</FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I>'cable max-cpe 1':</FONT></FONT=
></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I></FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I> http://www.cisco.com/univercd=
/cc/td/doc/product/cable/bbccmref/bbcmts.htm#xtocid42</FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I></FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I>The above link is an interestin=
g read. They can mess with your cable</FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I>connection in all sorts of odd =
and interesting ways.</FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I></FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I></FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I></FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I>KC Linux Users Group -- to unsu=
bscribe send mail to majordomo at kclug.org</FONT></FONT></I>
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I>Enter without the quotes in bod=
<FONT COLOR=3D"#737373"><FONT SIZE=3D"3"><I></FONT></FONT></I></PRE>
</BLOCKQUOTE>
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<FONT SIZE=3D"2"><B>Bill Cavalieri</FONT></B>
<BR>
<A HREF=3D"mailto:bcavalieri at gekl.net"><FONT SIZE=3D"2">bcavalieri at gekl.net=
</FONT></A>
<BR>
<FONT SIZE=3D"2">VP IT Systems</FONT>
<BR>
<FONT SIZE=3D"2">816 880 0066</FONT>
<BR>
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