Communications problems occur when the two peers cannot successfully establish a link. Sometimes these problems are actually negotiation problems that are caused by incorrectly configured chat scripts. This section contains information for clearing communications problems. For clearing negotiation problems that are caused by a faulty chat script, see Table 31–5.
Become superuser on the local machine. Then call the peer.
Call the remote peer. Then enable debugging features.
% pppd debug call peer-name |
You might need to obtain debugging information from the peer in order to fix certain communications problems.
Check the resulting logs for the communications problems in the next table.
Table 31–3 General Communications Problems That Affect PPP
Symptom |
Problem |
Solution |
---|---|---|
too many Configure-Requests |
One peer cannot hear the other peer. |
Check for the following problems:
|
The pppd debug output shows that LCP starts, but higher-level protocols fail or show CRC errors. |
The asynchronous control character map (ACCM) is incorrectly set. |
Use the default-async option to set the ACCM to the standard default of FFFFFFFF. First try to use default-async as an option to pppd on the command line. If the problem clears, then add default-async to /etc/ppp/options or to /etc/ppp/peers/peer-name after the call option. |
The pppd debug output shows that IPCP comes up but terminates immediately. |
IP addresses might be incorrectly configured. |
|
The link exhibits very poor performance. |
The modem might be incorrectly configured, with flow-control configuration errors, modem setup errors, and incorrectly configured DTE rates. |
Check the modem configuration. Adjust the configuration, if necessary. |