Linux Network Administrator Guide, Second Edition

Your Modem Does Not Dial

If your modem doesn't indicate that the DTR line has been raised when uucico calls out, you might not have given the right device to uucico. If your modem recognizes DTR, check with a terminal program that you can write to the modem. If this works, turn on echoing with E at the start of the modem chat. If the modem doesn't echo your commands during the modem chat, check if your line speed is too high or low. If you see the echo, check if you have disabled modem responses or set them to number codes. Verify that the chat script itself is correct. Remember that you have to write two backslashes to send one to the modem.

Your Modem Tries to Dial but Doesn't Get Out

Insert a delay into the phone number, especially if you have to dial a special sequence to gain an outside line from a corporate telephone network. Make sure you are using the correct dial type, as some telephone networks support only one type of dialing. Additionally, double check the telephone number to make sure it's correct.

Login Succeeds, but the Handshake Fails

Well, there can be a number of problems in this situation. The output in the log file should tell you a lot. Look at what protocols the remote site offers (it sends a string P protlist during the handshake). For the handshake to succeed, both ends must support at least one common protocol, so check that they do.

If the remote system sends RLCK, there is a stale lockfile for you on the remote system already connected to the remote system on a different line. Otherwise, ask the remote system administrator to remove the file.

If the remote system sends RBADSEQ, it has conversation count checks enabled for you, but the numbers didn't match. If it sends RLOGIN, you were not permitted to log in under this ID.

Log Files and Debugging

When compiling the UUCP suite to use Taylor-style logging, you have only three global log files, all of which reside in the spool directory. The main log file is named Log and contains all the information about established connections and transferred files. A typical excerpt looks like this (after a little reformatting to make it fit the page):

uucico pablo - (1994-05-28 17:15:01.66 539) Calling system pablo (port cua3)
uucico pablo - (1994-05-28 17:15:39.25 539) Login successful
uucico pablo - (1994-05-28 17:15:39.90 539) Handshake successful
               (protocol 'g' packet size 1024 window 7)
uucico pablo postmaster (1994-05-28 17:15:43.65 539) Receiving D.pabloB04aj
uucico pablo postmaster (1994-05-28 17:15:46.51 539) Receiving X.pabloX04ai
uucico pablo postmaster (1994-05-28 17:15:48.91 539) Receiving D.pabloB04at
uucico pablo postmaster (1994-05-28 17:15:51.52 539) Receiving X.pabloX04as
uucico pablo postmaster (1994-05-28 17:15:54.01 539) Receiving D.pabloB04c2
uucico pablo postmaster (1994-05-28 17:15:57.17 539) Receiving X.pabloX04c1
uucico pablo - (1994-05-28 17:15:59.05 539) Protocol 'g' packets: sent 15,
                resent 0, received 32
uucico pablo - (1994-05-28 17:16:02.50 539) Call complete (26 seconds)
uuxqt pablo postmaster (1994-05-28 17:16:11.41 546) Executing X.pabloX04ai
               (rmail okir)
uuxqt pablo postmaster (1994-05-28 17:16:13.30 546) Executing X.pabloX04as
               (rmail okir)
uuxqt pablo postmaster (1994-05-28 17:16:13.51 546) Executing X.pabloX04c1
               (rmail okir)

The next important log file is Stats, which lists file transfer statistics. The section of Stats corresponding to the above transfer looks like this (again, the lines have been split to fit the page):

postmaster pablo (1994-05-28 17:15:44.78)
                  received 1714 bytes in 1.802 seconds (951 bytes/)
postmaster pablo (1994-05-28 17:15:46.66)
                  received 57 bytes in 0.634 seconds (89 bytes/)
postmaster pablo (1994-05-28 17:15:49.91)
                  received 1898 bytes in 1.599 seconds (1186 bytes/)
postmaster pablo (1994-05-28 17:15:51.67)
                  received 65 bytes in 0.555 seconds (117 bytes/)
postmaster pablo (1994-05-28 17:15:55.71)
                  received 3217 bytes in 2.254 seconds (1427 bytes/)
postmaster pablo (1994-05-28 17:15:57.31)
                  received 65 bytes in 0.590 seconds (110 bytes/)

The third file is Debug. Debugging information is written here. If you use debugging, make sure this file has protection mode 600. Depending on the debug mode you select, it may contain the login and password you use to connect to the remote system.

If you have some tools around that expect your log files to be in the traditional format used by HDB- compatible UUCP implementations, you can also compile Taylor UUCP to produce HDB-style logs. This is simply a matter of enabling a compile-time option in config.h.

Chapter 17. Electronic Mail

Electronic mail transport has been one of the most prominent uses of networking since the first networks were devised. Email started as a simple service that copied a file from one machine to another and appended it to the recipient's mailbox file. The concept remains the same, although an ever-growing net, with its complex routing requirements and its ever increasing load of messages, has made a more elaborate scheme necessary.

Various standards of mail exchange have been devised. Sites on the Internet adhere to one laid out in RFC-822, augmented by some RFCs that describe a machine-independent way of transferring just about anything, including graphics, sound files, and special characters sets, by email.[105] CCITT has defined another standard, X.400. It is still used in some large