mra@srchtec.uucp (Michael Almond) (11/25/90)
We were recently discussing the cost of connecting to the internet. Someone mentioned a magic number of $100 per month to connect to the net. The lowest price I had found at the time was a SLIP connection to PSInet for $250. We'll David Smith from PSI gave me a call earlier this week to let me know, due to some cost reductions in hardware, they will be offering SLIP connections to PSInet for $150 a month. This deal will only last until the end of the year though. I suppose they are testing the water to see if price really does effect their market. Anyway, we are definitely going with PSInet. The Atlanta POP will be up sometime in January and I can let you everyone know what SLIPing is like on the internet. The only bad aspect of SLIPing I can see so far is that PSInet will not call us when they see packets with our address in them. However, our LAN will call PSInet because we're using a NetBlazer. One other item: PSI says we will not have a constant IP #. It supposedly changes each time we establish a connection with them. However, our address will remain constant (probably searchtech.com). I'm hoping this will not cause too many problem with our local setup, but I guess we're going to find out! --- Michael R. Almond (Georgia Tech Alumnus) mra@srchtec.uucp (registered) search technology, inc. emory!stiatl!srchtec!mra Atlanta, Georgia (404) 441-1457 (office) [search]: Systems Engineering Approaches to Research and Development
jclark@sdcc6.ucsd.edu (John Clark) (11/25/90)
In article <315@srchtec.UUCP> mra@srchtec.uucp (Michael Almond) writes: >We were recently discussing the cost of connecting to the internet. Someone >mentioned a magic number of $100 per month to connect to the net. The lowest >price I had found at the time was a SLIP connection to PSInet for $250. I have some questions about PSInet. Does anyone know the answer to the following: 1) Does it exist in Southern California? 2) If it does are there one time charges and then monthly plus connect charges? 3> Does one's SLIPped Internet number change from one connect to another. Or can one have an assigned Internet number for Mail etc. -- John Clark jclark@ucsd.edu
schoff@PSI.COM ("Martin Lee Schoffstall") (11/25/90)
In article <315@srchtec.UUCP> mra@srchtec.uucp (Michael Almond) writes: >We were recently discussing the cost of connecting to the internet. Someone >mentioned a magic number of $100 per month to connect to the net. The lowest >price I had found at the time was a SLIP connection to PSInet for $250. I have some questions about PSInet. Does anyone know the answer to the following: 1) Does it exist in Southern California? LA 2) If it does are there one time charges and then monthly plus connect charges? One time charge of $150. 3> Does one's SLIPped Internet number change from one connect to another. Or can one have an assigned Internet number for Mail etc. Mail is handled by {uucp,pcmail,pop} protocols and MX records, its not an issue. John Clark jclark@ucsd.edu
nraoaoc@nmt.edu (NRAO Array Operations Center) (11/27/90)
In article <315@srchtec.UUCP> mra@srchtec.uucp (Michael Almond) writes: >[...] >One other item: PSI says we will not have a constant IP #. It supposedly >changes each time we establish a connection with them. However, our address >will remain constant (probably searchtech.com). I'm hoping this will not cause >too many problem with our local setup, but I guess we're going to find out! Say what????? I fail to see how this can be the case. Granted they can change their tables any time they want, *but* they have the following restrictions: a) they have to use an Internet number assigned to them/you by the NIC b) the rest of the Internet has to understand the routing (if it's advertised, and if it isn't no-one can reach you) c) your system has to know *before establishing the connection* what its own Internet address is Are you sure that they meant your "IP #" changes? If you are connecting through SLIP, then your circuit number might change each time, depending how many other connections are being made at the same time. But your own actual Internet address should stay the same. Even if it *could* be done, it would be such an administrative nightmare trying to figure out "who's 123.456.789.10 this morning?" that I can't think why they *would* do it. I dunno, maybe the connections are volatile enough that they just assign an IP address in sequence or something every time a connections comes up, but it sounds pretty weird to me. -- Ruth Milner Systems Manager NRAO/VLA Socorro NM rmilner@zia.aoc.nrao.edu
lars@spectrum.CMC.COM (Lars Poulsen) (11/30/90)
In article <315@srchtec.UUCP> mra@srchtec.uucp (Michael Almond) writes: >>One other item: PSI says we will not have a constant IP #. It supposedly >>changes each time we establish a connection with them. However, our address >>will remain constant (probably searchtech.com). In article <1990Nov26.233848.20828@nmt.edu> rmilner@zia.aoc.nrao.edu (Ruth Milner) writes: >I fail to see how this can be the case. Granted they can change their tables >any time they want, *but* they have the following restrictions: > > a) they have to use an Internet number assigned to them/you by the NIC > b) the rest of the Internet has to understand the routing (if it's > advertised, and if it isn't no-one can reach you) > c) your system has to know *before establishing the connection* what > its own Internet address is > ... >Even if it *could* be done, it would be such an administrative nightmare >trying to figure out "who's 123.456.789.10 this morning?" that I can't think >why they *would* do it. > >Ruth Milner >Systems Manager NRAO/VLA Socorro NM Ruth, The network number stays constant, the IP address changes. (The confusion seems to have been caused by a bad choice of words: The posting says "internet number" for "IP address" and "address" for "fully qualified domain name".) Crazy as it seems at first glance, dynamic IP addresses are not actually all that unusual. Client-only PC's often do this. And with domain name service, it is doable even to handle incoming connections. Yes, it does create a few management hassles. You need to have a name server with a transaction interface to change the name/address mappings on the fly (where the run-of-the-mill BIND just reads a table when it is reloaded) and you cannot have management utilities that assume that name/address mappings are constant. But technically, at the low level, it is no harder than ARP. You need an ARP-like handshake before you switch to IP mode. Most SLIP interfaces already have a handshake (unix login !) before turning into IP interfaces, so there definitely is a mechanism to do that. As to WHY one wants to do this ? When you have a couple hundred PC's around, it is easier to just declare them to be generic than to try to keep track of locations and owners for all of them. Likewise, network providers may have only allocated class C network numbers for a routing cluster, and may prefer the dynamic addresses over changing backbone routing implementations with hardcoded netmasks. / Lars -- / Lars Poulsen, SMTS Software Engineer CMC Rockwell lars@CMC.COM
urlichs@smurf.sub.org (Matthias Urlichs) (12/01/90)
In comp.protocols.tcp-ip, article <1990Nov29.212559.7284@spectrum.CMC.COM>, < < Crazy as it seems at first glance, dynamic IP addresses are < not actually all that unusual. Client-only PC's often do this. And with < domain name service, it is doable even to handle incoming connections. < < Yes, it does create a few management hassles. You need to have a < name server with a transaction interface to change the name/address < mappings on the fly (where the run-of-the-mill BIND just reads a table < when it is reloaded) and you cannot have management utilities that < assume that name/address mappings are constant. < Problem 1: Name server records get cached. A TTL of five minutes is probably not a good idea. Problem 2: What if my connection breaks (noisy phone line, idle connection timeout) and I have to reconnect? Suddenly my IP number is different: and the existing connection is broken for good. Not good either. < As to WHY one wants to do this ? When you have a couple hundred < PC's around, it is easier to just declare them to be generic than to try < to keep track of locations and owners for all of them. Likewise, network < providers may have only allocated class C network numbers for a routing < cluster, and may prefer the dynamic addresses over changing backbone < routing implementations with hardcoded netmasks. < That might work for PCs or similar clients, but for external SLIP/PPP connections (which might even have their own Class C network hanging off the remote end) it seems to be preferable to give each client its own IP address. -- Matthias Urlichs -- urlichs@smurf.sub.org -- urlichs@smurf.ira.uka.de /(o\ Humboldtstrasse 7 - 7500 Karlsruhe 1 - FRG -- +49+721+621127(0700-2330) \o)/