Installation guide

SLIP/PPP Problems
4-12
• Verify that flow control is functioning properly.
By default, the low 32 characters of the ASCII set are not sent across an asynchronous
line in the clear. They are "byte-stuffed." LCP allows the user to specify that some of
these characters are sent in the clear. If this is done, then possibly a character that is
being sent in the clear is being acted upon by the underlying hardware or software. For
example, XON/XOFF may be sent in the clear as data, when at the same time the
hardware is using XON/XOFF flow control.
• If LCP PAP or CHAP authentication is enabled, verify that the PC supports PAP or
CHAP and has the correct password. The password must match the server login
password. If USERNAME is specified for LCP authentication, the username and
password are used for authentication and must match a valid username and password
pair at the proper authentication server. Both the username and the password are case-
sensitive.
• If the attached device wants the access server to authenticate itself, problems may
occur. The access server does not support this. Turn off authentication in the attached
device.
PPP IPCP (TCP/IP) Connections Fail
Check the following:
• For IP, IPCP must be in the OPEN state. To determine the state, enter the SHOW PORT
IPCP STATUS command and check the State field.
• The port characteristic IPCP must be enabled on the port. To determine if IPCP is
enabled, enter the SHOW PORT IPCP CHARACTERISTICS command and check the
IPCP field.
• If the IPCP COMPRESSION parameter is enabled for a port, then TCP/IP compression
must be in effect on the host system also.
PPP ATCP (AppleTalk) Connections Fail
Check the following:
• For AppleTalk, ATCP must be in the OPEN state. To determine the state, enter the
SHOW PORT ATCP STATUS command and check the State field.
• AppleTalk must be enabled on the access server or ATCP does not reach the OPEN
state. Refer to Chapter 5 for more information on troubleshooting AppleTalk problems.
• The port characteristic ATCP must be enabled. To determine if ATCP is enabled, enter
the SHOW PORT ATCP CHARACTERISTICS command and check the ATCP field.