Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!att!ucbvax!TERMINUS.UMD.EDU!dzoey From: dzoey@TERMINUS.UMD.EDU Newsgroups: comp.protocols.tcp-ip.ibmpc Subject: Re: TCP/IP over modem (I need SERIOUS help here) Message-ID: <9103281821.AA11157@terminus.umd.edu> Date: 28 Mar 91 18:21:04 GMT References: <3108@beguine.UUCP> Sender: daemon@ucbvax.BERKELEY.EDU Organization: The Internet Lines: 62 > From: Alan Gallatin > 1) Is there any truth to what I've heard? Can I run TCP/IP over a > modem? There are two "official" ways of running IP over a modem. The older, more widely implemented method is to use SLIP (serial line IP). I believe there is a SLIP packet driver, and all the commercial implementations support SLIP. SLIP has some administrative shortcommings, such as assignment of IP addresses and authentication. If you're the only one dialing into a slip server (many (most?) unix boxes can be configured as slip servers) the addressing problem is less important. The other way of running IP over serial lines is to use PPP (Point to Point Protocol). This solves the shortcomings of slip, but since it's a new protocol, isn't as widely implemented. I don't know if there's a PD PPP packet driver. > 2) Aside from speed, what differences will I notice between this > implementation and an "ethernet-ed" IBM running "TELBIN / TN3270" and > "FTP"? There are different administrative issues involving address generation and security. Once you've set up the SLIP connection, you shouldn't notice any difference though. In fact, you probably won't notice a lot of difference in telnet at all. > 4) Do I need the cooperation of a current internet machine for me to > access the internet and, if so, what does that machine need to provide > me with? Yes. You need a machine to talk to that runs the protocol you're running (SLIP or PPP). There are PD implementation of SLIP for various OS's and there are some PD implementations of PPP for some flavors of unix. Many TCP/IP vendors will be offering PPP products shortly if they don't already, and most, if not all currently offer SLIP service. > 5) Do I need any TECHNICAL knowledge of TCP/IP packet structure, > ethernet, internet, etc. or is a good working knowledge of IBM and > internet USAGE sufficient? You may need to know how to assign an IP address to your slip implementation. > 6) Do I really want to do this???? (Don't bother answering this one - > the questions above are what I really need!) It's really not that bad. There are a couple of magic numbers you need to know that vary between installations, but once you've done it once it's trivial. I wouldn't try SLIP using anything under 9600 baud. PPP has some compression options (I think, not sure) that make 2400 painful, but usable. Good luck, Joe Herman dzoey@terminus.umd.edu