On Sat, Feb 07, 2004 at 01:05:32PM +0200, Oleg Goldshmidt wrote: > Itamar Ravid <[EMAIL PROTECTED]> writes: > > > While talking to the representative, he mentioned something > > regarding direct connections using DHCP. I asked him more about it, > > and got the answer that I only have to call Aruzey Zahav, verify the > > matter with them and the PPTP tunnel issue will be gone and I will > > connect directly using DHCP. I`m using cables, by the way. > > OK, I recently switched from ADSL (via PPTP, of course) to cable, and > I am connected through DHCP now, no PPTP, so I went through he whole > procedure. Here is the deal as I understand it (my ISP is not Internet > Zahav but 012, I doubt it makes any difference). > > The cable company gives you the physical infrastructure, including > modem, and connects you to their DHCP server. They do not, however, > connect you to the internet, in the sense that you are not routed to > any interesting places beyond the cable company itself. You can get > to the cable web site, check the connection speed, download an ISP > dialer if you need one, and that's about it. > > Your real Internet connection is handled by the ISP. In general, they > need to give you an IP address from the pool assigned to them. To that > end, they can make you dial into their server via PPTP, and once you > do that your ppp0 interface gets an IP address and whatever you send > out of it gets routed to the rest of the universe. Or they can tell > the cable company to set their (the cable company's) DHCP server to > give you a semi-permanent (very long lease) IP address from the ISP's > pool, and thus your eth[0-9] interface becomes your link to the world, > no dialer needed. > > So, the cable company is right - they need an authorization from the > ISP to connect you without a dialer. They cannot give you an address > from the ISP's pool without it. How you arrange matters with the ISP > is between you and them though. In my case, the cable company > initially screwed up and I was listed with them as requiring a dialer. > Once 012 sent an email to AZ they switched me to DHCP. I am getting a > business grade service, but I don't know if PPTP-less connection is > conditioned on that. > > The security issue has been discussed here in the past. Check the > archives. Shachar Shemesh pointed out, rightly, that if someone forges > your MAC address (something that is well beyond the technical ability > of my elderly next-door neighbours, but in general feasible), gets
Its actually quite easy to do. I reset mine once when trying to fix a faulty card. If some sits at a point that they can sniff you network traffic they can get the mac address from the arp requests and then change the address on their card. Look at http://www.scyld.com/diag/index.html. DISCLAIMER: Note that this tool is intended for fixing ethernet card problems not for any criminal activity so don't take this as a link for a hacking tutorial. I found it very useful to diagnose and partly fix my broken onboard rtl on my laptop and just thought other people may also. > your IP address, and starts sending encrypted emails to known Al Qaeda > operators and/or drug traffickers, or spams the world with child > pornography, you may get visitors at an inconvenient hour. > > > The point in this post - I was wondering if there is anyone here who > > connects directly using DHCP. Using the PPTP dialer slows my > > boot-process by ~15 seconds, since the PPTP tunnel apparently takes > > some time to be established. Also, if I wasn't using a GRE tunnel, > > my Netfilter matters would be less complicated. > > Boot time was never an issue for me - I keep my computers and > connections on. I didn't change my iptables rules except that my > internet interface is now eth0 and not ppp0, which was a change in a > variable assignment at the top of the script. YMMV - your needs may be > different. > > A big difference for me is that the connection is now *much* more > reliable - ADSL was dropped from time to time, especially during > Saturdays. Cable seems much more stable, but whether or not it is > related to cable vs. ADSL or to DHCP vs. PPTP I cannot say. > I don't think that its ADSL since I am on adsl and I loose my connection only during power outage (the electricity in my house is not very good so that would mean every few days when the cap pops ;-( it also happened once when someone rammed the telephone pole ;-) I think its more a question of isp or maybe DHCP vs. PPTP. > -- > Oleg Goldshmidt | [EMAIL PROTECTED] > > ================================================================= > To unsubscribe, send mail to [EMAIL PROTECTED] with > the word "unsubscribe" in the message body, e.g., run the command > echo unsubscribe | mail [EMAIL PROTECTED] > > > +++++++++++++++++++++++++++++++++++++++++++ > This Mail Was Scanned By Mail-seCure System > at the Tel-Aviv University CC. > ================================================================= To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
