Originally Posted by geetarman
Thx - muchly for your responce. I think I've got that part covered - honestly my challenge is the dial in server - I saw some old stuff on mgetty but I'm not sure if that's the way to do it if you have an 8 port modem PCI card... I got the card operating fine - drivers etc... It's the dial in server and then once the modem connection is made, how the server shares the network to the dial up users... That's where i'm a bit grey.
Basically you create a PPP (Point-to-Point Protocol) dial in server that can service the 8 ports. Use DHCP (Dynamic Host Configuration Protocol) to assign each dial in client an IP address.
When a client wants to access a shared folder, it either has a drive permanently mapped to the share, or a login script that maps the drive. The SMB (Server Message Block) protocol is used through TCP/IP port 445 or 139.
In order for a client to access a share on a server, the client has to know the server's IP address. One way to do that is use the IP address in place of the server name. Another way is through some kind of name resultion protocol.
You can provide a DNS (Domain Name System) server to allow the clients to find your server's IP address from the name (or define the name and IP address in the "hosts" file on the clients)
You may be able to get NetBIOS name service working if you can provide that service in SAMBA. NetBIOS name service uses broadcasts on UDP port 137. When a server sees a broadcast request with its name, the server responds to the client. In order for that to work, the client has to be configured to route NetBIOS UDP broadcasts to the modem (PPP). NetBIOS name service, DNS or the hosts file are all ways for a client to get a server's IP address from the server name. I'm not sure which of those will work with a DOS client.
Here are the various ports involved in SMB and NetBIOS.
UDP 137 - NetBIOS name resolution (broadcast and reply)
UDP 138 - NetBIOS datagram service (broadcast or direct)
TCP 139 - NetBIOS session (connection)
TCP 445 - SMB session
NOTE: SMB can use port 139 (NetBIOS session) if 445 is not available.
Port 138 is used mostly by the computer browser that maintains a list of the server computers on the network. The computer browser normally doesn't work through a dial up connection.
Here is how the dial in process works.
The modem answers the phone and the client logs in to the serial terminal port. The PPP protocol attaches to the serial terminal port. The client uses DHCP to request an IP address. The DHCP server responds with the IP address, default gateway and DNS server addresses.
When the client attempts to access a share on the server, first it tries to resolve the server name to an IP address. That's done by the "hosts" file on the client, DNS on the server, or NetBIOS name service provided by the server.
Once the client has the server's IP address then the client establishes an SMB session using port 445 or through NetBIOS using port 139. SMB protocol is used to access the shared files.
Since the PPP connection carries IP protocol, any of the normal UDP or TCP service ports can be accessed on the server. The client can use telnet or other services.