58 lines
2.5 KiB
HTML
58 lines
2.5 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
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<!--Converted with LaTeX2HTML 96.1-c (Feb 29, 1996) by Nikos Drakos (nikos@cbl.leeds.ac.uk), CBLU, University of Leeds -->
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<HTML>
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<HEAD>
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<TITLE>Displaying Connections</TITLE>
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</HEAD>
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<BODY LANG="EN">
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<A HREF="node1.html"><IMG WIDTH=65 HEIGHT=24 ALIGN=BOTTOM ALT="contents" SRC="contents_motif.gif"></A> <BR>
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<B> Next:</B> <A HREF="node78.html">Checking the ARP Tables</A>
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<B>Up:</B> <A HREF="node74.html">Checking with netstat</A>
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<B> Previous:</B> <A HREF="node76.html">Displaying Interface Statistics</A>
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<BR> <P>
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<H2><A NAME="SECTION007930000">Displaying Connections</A></H2>
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Netstat supports a set of options to display active or passive
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sockets. The options -t, -u, -w, and
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-x show active TCP, UDP, RAW, or UNIX socket connections.
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If you provide the -a flag in addition, sockets that are
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waiting for a connection (i.e. listening) are displayed as well.
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This will give you a list of all servers that are currently running
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on your system.
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<P>
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Invoking netstat -ta on vlager produces:
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<pre>
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$ netstat -ta
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Active Internet connections
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Proto Recv-Q Send-Q Local Address Foreign Address (State)
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tcp 0 0 *:domain *:* LISTEN
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tcp 0 0 *:time *:* LISTEN
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tcp 0 0 *:smtp *:* LISTEN
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tcp 0 0 vlager:smtp vstout:1040 ESTABLISHED
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tcp 0 0 *:telnet *:* LISTEN
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tcp 0 0 localhost:1046 vbardolino:telnet ESTABLISHED
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tcp 0 0 *:chargen *:* LISTEN
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tcp 0 0 *:daytime *:* LISTEN
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tcp 0 0 *:discard *:* LISTEN
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tcp 0 0 *:echo *:* LISTEN
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tcp 0 0 *:shell *:* LISTEN
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tcp 0 0 *:login *:* LISTEN
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</pre>
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This shows most servers simply waiting for an incoming connection. However,
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the fourth line shows an incoming SMTP connection from vstout, and
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the sixth line tells you there is an outgoing telnet connection
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to vbardolino.<A HREF="footnode.html#3193"><IMG ALIGN=BOTTOM ALT="gif" SRC="foot_motif.gif"></A>
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<P>
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Using the -a flag all by itself will display all sockets
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from all families.
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<HR>
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<P><ADDRESS>
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<I>Andrew Anderson <BR>
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Thu Mar 7 23:22:06 EST 1996</I>
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</ADDRESS>
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</BODY>
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</HTML>
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