It's possible to return a true/false answer on an "is X a part of list Y" in what is called O(log N), where N is the size on Y, this means that the time to answer that question grows in logarithmic proportion to the increase in the size of the list. It's also possible to answer that question in constant time on average, that is the time to answer the question doesn't change for any size list Y.
So in fact an answer can be given very fast, no need to calculate how many possible name-string are possible. I'm sure checking a constant IP range can be much more efficient, and maybe they run that test in parallel, but the fact is: Now I'm connected to Internet-Zahav, meaning I have an Internet-Zahav IP, and still this massage is sent trough mailgw.netvision.net.il. At 15:39 16/12/2001, you wrote: >-=O0~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~O0=- > "He took his vorpal sword in hand: > Long time the manxome foe he sought - > So rested he by the Tumtum tree. > And stood awhile in thought." > > [L.Carrol "Jabberwacky"] > >On Sun, 16 Dec 2001, Refael Ackermann wrote: > > > I'm using mailgw.netvision.net.il, and Eudora as client. > > To be more specific about what I've figured as the needed header format: > > The header must contain a valid netvision address anywhere (including the > > "To" field). > > Theoreticly searching the acount names DB shouldn't be more complicated > > then searching the IP range. >i don't know which theory you are using: > >let us roughly assume that the usernames are of the length >6 characters, and each can be a-z,_,-,0-9 which makes more than 30 letters; >to search all of them it is 20 in the power of 6. >afaik the addresses in IPv4 are in hex form of 0xFF.0xFF.0xFF.0xFF >to count all the IPs is 6 caracters of 16 letter aleph-beth. >it makes 16 in the power of 6. >so ... >which is bigger: 16^6 or more_than_30^6 ?? > > > And af far as being "spam freindly", it is, but it's allso useful for me as > > a legitimate user. > > > > > > > > At 09:43 16/12/2001, you wrote: > > >I do not think its likely that they check accounts on RCPT whenever an > > >incoming SMTP session is in progress - first, I don't think that sendmail > > >has that capability, and second, checking against the Netvision huge > > >database (which includes defunct as well as active acounts) is a huge > > >preformance hog, and I personally would have never designed such a system. > > >through which server do you relay ? I tried mailgw.netvision.net.il > > > > > >Oded > > > > > >-- > > >"A Meltdown? One of those annoying buzzwords. We prefer to think of it > as an > > >unrequested fission surplus!" > > > -- Montegue Burns, (The Simpsons) > > > > > > > > >----- Original Message ----- > > >From: "Refael Ackermann" <[EMAIL PROTECTED]> > > >To: "Oded Arbel" <[EMAIL PROTECTED]> > > >Cc: <[EMAIL PROTECTED]> > > >Sent: Saturday, December 15, 2001 10:05 PM > > >Subject: Re: (OT) ISP's that don't allow relaying > > > > > > > > > > At 19:12 15/12/2001, you wrote: > > > > >Not as far as I know - I just tried to telnet to the Netvision mail gw > > >and > > > > >tried to send mail using a mail from address of an old netvision > > >account - > > > > >it reject my rcpt to command with a 'not relaying' error message. I'm > > > > >connection through actcom. > > > > > > > > > >AFAIK Netvision blocks by IP lists, and if you succeed in sending mail > > > > >through Netvision while connected to Internet Zahav, then I have to > > >conclude > > > > >that Netvision's IP lists are not accurate. > > > > > > > > > > > > I'm sure they block by address, since if I try to send with a different > > > > address in the replay-to, only then they block me. > > > > From what you've writen I geuss you have to have a live acount to do > > >relaying. > > > > > > > > > > > > > > ================================================================= > > 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] > > ================================================================= 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]
