SERVERS(6) XR32 REFERENCE MANUAL 26/3/2013
NAME
SERVERS -- Servers Available in XR32.
DESCRIPTION
In the XR32 context, servers are processes which accept
connections or data from users (i.e. clients) and provide
specific services (e.g. file transfer) to those clients.
They are often associated with a specific TCP or UDP "service
port" number, for example TCP port 21 for file transfer, UDP
port 53 for DNS server and so on.
XR32 contains a number of servers and makes them available by
default, although they may be disabled by the sysop if
necessary.
The policy of making services available by default is an
attempt to provide useful services to the Amateur Radio Packet
Network (amprnet) with minimal effort on the part of the
sysop. If services were disabled by default, most sysops
wouldn't enable them, either because they didn't understand
them, or because they couldn't be bothered.
Access to the benign servers is unrestricted, but most are
protected by password and IP access control lists.
The following servers are available in XR32
Name Port Proto Function
---------------------------------------------------
ECHO 7 TCP Echoes data back
DISCARD 9 TCP Discards data
FTP 21 TCP File Transfer
TELNET 23 TCP XR32 user session
DNS 53 UDP Domain Name System
FINGER 79 TCP User information
HTTP 80 TCP Web server
TTYLINK 87 TCP XR32 user session
RLOGIN 513 TCP Remote Login (sysop)
SOCKS 1080 TCP SOCKS Proxy
APRS 1448 TCP Serves APRS data
TELPROXY 2323 TCP Raw TCP to AX25 bridge
CHAT 3600 TCP Conferencing
AGWHOST 8000 TCP AGW Packet Engine emulator
RHP 9000 TCP Remote application support
PMS - - Personal Mail Server
For details of how to move the above ports or disable the
servers, please see the TCP-PORTS page.
Brief Overview Of XR32 Servers
==============================
ECHO
~~~~
Anything the user sends is echoed back to him. This is a
useful tool for test purposes. This server is also available
from the command prompt.
DISCARD
~~~~~~~
This simply dumps anything sent to it. It is another useful
tool for test purposes. This server is also available from the
command prompt.
FTP
~~~
Allows sysops to upload, download, move and rename files,
create and remove directories etc. Not available to users.
TELNET
~~~~~~
Provides regular user access to the XR32 command prompt.
DNS
~~~
Answers Domain Name System (DNS) queries, to provide a
hostname to IP-address translation service.
FINGER
~~~~~~
Allows users to retrieve information about other users or any
other topics provided by the sysop. This server is also
available from the command prompt.
HTTP
~~~~
Serves HTML (web) pages, and provides a rudimentary browser
interface to XR32.
TTYLINK
~~~~~~~
Provides regular user access to the XR32 command prompt, i.e.
duplicates the function of port 23.
RLOGIN
~~~~~~
Secure remote login for sysops only, providing full syop-mode
access.
SOCKS Proxy
~~~~~~~~~~~
Circuit level proxy allowing applications to access external
services through a firewall as an alternative to NAT.
APRS
~~~~
Shares APRS data between clients such as UI-View, RF ports and
the Internet APRS-IS systems.
TELPROXY
~~~~~~~~
The Telnet Proxy server allows TCP/IP applications to make
fully transparent raw binary connections (i.e. ones capable of
handling compressed forwarding) to AX25 or NetRom
destinations.
CHAT
~~~~
Allows groups of users to hold conferences, either locally or
globally via a network of interconnected servers.
AGWHOST
~~~~~~~
Emulates the AGW TCP host interface, enabling XR32 to support
applications (e.g. UI-View) that were designed for use with
the AGW Packet Engine.
RHP
~~~
Allows XR32 to support a wide range of applications which may
be located on the same PC or remotely.
PMS
~~~
A no-frills mailbox which can handle both private mail and
bulletins. It is available from AX25 and the XR32 command
prompt, but currently has no TCP port of its own.
SEE ALSO
CHAT-SRV(6) -- Chat Server
DISCARD(1) -- Start a Sink Session
ECHO(1) -- Start an Echo Session
FINGER(1) -- Display User Information
TCP-PORTS(6) -- TCP Server Ports
SERVERS(6) END OF DOCUMENT
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