Tracy, I've run into the same thing you are (although I know this is two years after the fact). I discovered here that the ports we're talking about are related to telnet streams on rotary ports.
Table: TCP Port Telnet Access to Cisco Products (Earlier Releases)
| TCP Port Number | Access Method |
|---|
7 | Echo |
9 | Discard |
23 | Telnet (to virtual terminal VTY ports in rotary fashion) |
79 | Finger |
1993 | SNMP over TCP |
2001 through 2999 | Telnet to auxiliary (AUX) port, terminal (TTY) ports, and virtual terminal (VTY) ports |
3001 through 3999 | Telnet to rotary ports (access via these ports is only possible if the rotaries have been explicitly configured first with the rotary command) |
4001 through 4999 | Telnet (stream mode) mirror of 2000 range |
5001 through 5999 | Telnet (stream mode) mirror of 3000 range (access via these ports is possible only if the rotaries have been explicitly configured first) |
6001 through 6999 | Telnet (binary mode) mirror of 2000 range |
7001 through 7999 | Telnet (binary mode) mirror of 3000 range (access via these ports is possible only if the rotaries have been explicitly configured first) |
8001 through 8999 | Xremote (communication servers only) |
9001 through 9999 | Reverse Xremote (communication servers only) |
10001 through 19999 | Reverse Xremote rotary (communication servers only; access via these ports is possible only if the ports have been explicitly configured first) |
Digging a little deeper, I discovered that the AUX port on a router is available via TCP. At the router, execute
router#show line
In my case on a Cisco 2501 I got:
router#show line
Tty Typ Tx/Rx A Modem Roty AccO AccI Uses Noise Overruns Int
* 0 CTY - - - - - 2 0 0/0 -
1 AUX 9600/9600 - - - - - 15 0 0/0 -
2 VTY - - - - - 35 0 0/0 -
3 VTY - - - - - 2 0 0/0 -
4 VTY - - - - - 0 0 0/0 -
5 VTY - - - - - 0 0 0/0 -
6 VTY - - - - - 0 0 0/0 -
More digging around about configuring AUX ports found this article. It describes how to configure and access the AUX ports via a telnet session. Basically, you start at 2000, 4000, 6000, or 9000, and then add the line number for the AUX port. As you can see above, the line number for my AUX port is 1, so if I want to telnet to that port, I would use
router>telnet 10.100.0.254 2001 or 4001 or 6001 or 9001
AUX ports start at AUX 0 and by default these ports are on, even though there may not be anything about them in the configuration. To turn the AUX port off, you do it the same way as you do with a VTY line.
router#conf t
router(config)#line aux 0
router(config-line)#transport input none
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