Technical data

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Conﬁguring Serial Lines

3.4 Solving Serial Line Problems

• Are the modems conﬁgured properly?

• Are the DIP switches on the modems set correctly?

• Are the modem software settings correct? Make sure that ﬂow control is

disabled.

• Are all clients and dialup providers using unique addresses?

After a software upgrade, be sure to reboot and restart TCP/IP Services.

2. Make sure the SET HOST attempts have not exceeded the OpenVMS security

level. To check and then delete, if necessary, any information about these

attempts, enter the following commands. Note that SECURITY privilege

must be enabled to use these commands.

$ SHOW INTRUSION

$ DELETE/INTRUSION_RECORD source

3. Make sure that IP forwarding is enabled using the following command:

TCPIP> SHOW PROTOCOL IP/FORWARD

4. Make sure the terminal characteristics for the terminal device associated

with the interface are set up as follows:

$ SET TERMINAL TTnx /ALTYPEAHD /AUTOBAUD /DIALUP -

_$ /DISCONNECT /EIGHTBIT /MODEM /NOHANGUP /NOHOSTSYNC /NOPASTHRU -

_$ /NOREADSYNCH /NOTTYSYNCH /PERMANENT /TYPE_AHEAD

Make sure you specify the /TYPE_AHEAD qualiﬁer when you enter the SET

TERMINAL command to set up an asynchronous port.

5. Enter the SET HOST/DTE command to make sure you can log in to the

system:

$ SET HOST/DTE TTnx

If you cannot log in to or communicate with the system, you may be using the

wrong terminal device name (TTnx).

6. Set up OPCOM to receive messages using the DCL command

REPLY/ENABLE. You need OPER privileges to use OPCOM.

7. You need NETMBX and OPER privileges to establish a successful connection.

If these privileges are not enabled when you enter the CONNECT command,

you will see messages similar to the following:

$ PPPD

PPPD> CONNECT

\}‘}"}(}"6~ <CTRL/@>

%PPPD-I-CONNECTTERM, converting connection on device _TTA0: to a

Point-to-Point connection

%PPPD-E-CALLBACKERR, error calling network callback

%SYSTEM-F-NOPRIV, insufficient privilege or object protection violation

%PPPD-F-ABORT, fatal error encountered; operation terminated

Note that the extraneous data in this sample is an ASCII representation of IP

packets transmitted over the open line.

PPP sets up a default route on the client if one did not exist. Typically, a

default route exists if another interface exists on the client.

8. Attempt to ping the remote system:

TCPIP> PING host-name

Conﬁguring Serial Lines 3–15