Technical data
Configuring Serial Lines
3.3 Setting Up a SLIP Interface
To use proxy ARP with a DECserver terminal server, assign an IP address in the
same subnetwork as the terminal server.
At the terminal server, enter the TCP/IP management command SHOW PORT
SLIP. Verify that:
• An IP address has not already been associated with your port.
• Header compression is available, if you plan to use it.
3.3.5 Setting Up a SLIP Gateway with Proxy ARP
It is also possible to set up your host as a SLIP gateway with proxy ARP. You
might prefer this approach if your dialin modems are attached directly to an
OpenVMS system rather than to a terminal server.
Follow these steps on the host to become a SLIP gateway:
1. Create a SLIP interface in another network or subnetwork, for example:
$ TCPIP SET INTERFACE SL0 /HOST=10.1.2.3 /SERIAL_DEVICE=TTA2
2. Add a host route for the remote system. For example:
$ TCPIP SET ROUTE FINCH /GATEWAY=10.1.2.3
3. Configure an ARP entry for the remote host, listing your own Ethernet
address (as shown in TCPIP SHOW INTERFACE /FULL). For example:
$ TCPIP SET ARP 08-00-2B-2C-4F-46 FINCH /PUBLIC
4. Enable IP packet forwarding, if not already done. Enter:
$ TCPIP SET PROTOCOL IP /FORWARD
When your host is set up as a SLIP gateway, create an interface on the
remote host at the other end of the serial line. Specify an address in the same
subnetwork as the LAN.
Although the two ends of the SLIP line are in different subnetworks, traffic
can flow properly due to the interface route you added with the SET ROUTE
command.
3.3.6 Shutting Down SLIP
To terminate a SLIP connection, follow these steps:
1. Return the associated terminal port to general use. Enter:
$ TCPIP SET NOINTERFACE interface
2. If you added special route and proxy entries in conjunction with the SLIP
line, remove them.
3. If you changed any terminal settings in preparation for SLIP, restore them
using the SET TERMINAL command.
3.4 Solving Serial Line Problems
If you have problems dialing in to an OpenVMS system using SLIP or PPP after
following the instructions in this chapter, perform the following steps to isolate
the cause of the problem:
1. Check the equipment used by both the client and the dialin provider:
• Do the cables work?
3–14 Configuring Serial Lines