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><DIV
CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="LOWERWIN"
>Lower Window</A
></H1
><P
> The lower window displays information about the other types of traffic
on your network. The following protocols are detected:</P
><P
></P
><UL
COMPACT="COMPACT"
><LI
><P
>User Datagram Protocol (UDP)</P
></LI
><LI
><P
>Internet Control Message Protocol (ICMP)</P
></LI
><LI
><P
>Open Shortest-Path First (OSPF)</P
></LI
><LI
><P
>Interior Gateway Routing Protocol (IGRP)</P
></LI
><LI
><P
>Interior Gateway Protocol (IGP)</P
></LI
><LI
><P
>Internet Group Management Protocol (IGMP)</P
></LI
><LI
><P
>General Routing Encapsulation (GRE)</P
></LI
><LI
><P
>Address Resolution Protocol (ARP)</P
></LI
><LI
><P
>Reverse Address Resolution Protocol (RARP)</P
></LI
></UL
><P
> Unrecognized IP packets are indicated by their
protocol numbers while non-IP packets are indicated as
<TT
CLASS="COMPUTEROUTPUT"
>Non-IP</TT
>
in the lower window.</P
><DIV
CLASS="NOTE"
><P
></P
><TABLE
CLASS="NOTE"
WIDTH="100%"
BORDER="0"
><TR
><TD
WIDTH="25"
ALIGN="CENTER"
VALIGN="TOP"
><IMG
SRC="./stylesheet-images/note.gif"
HSPACE="5"
ALT="Note"></TD
><TH
ALIGN="LEFT"
VALIGN="CENTER"
><B
>Note</B
></TH
></TR
><TR
><TD
> </TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><P
>The source and destination addresses for ARP and
RARP entries are MAC addresses.</P
><P
> Strictly speaking, ARP and RARP packets aren't IP packets, since
they are not encapsulated in an IP datagram. They're
just indicated because they are integral to proper IP operation on LANs.</P
></TD
></TR
></TABLE
></DIV
><P
> For all packets in the lower window, only the first IP fragment is
indicated (since that contains the header
of the IP-encapsulated protocol) but with no further information
from the encapsulated protocol.</P
><P
>UDP packets are also displayed
in
<TT
CLASS="COMPUTEROUTPUT"
><TT
CLASS="REPLACEABLE"
><I
>address</I
></TT
>:<TT
CLASS="REPLACEABLE"
><I
>port</I
></TT
></TT
> format while ICMP entries also contain the
ICMP message type. For easier location, each type of protocol
is color-coded (only on color terminals such as the Linux console).</P
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
>UDP</DT
><DD
><P
>Red on White</P
></DD
><DT
>ICMP</DT
><DD
><P
>Yellow on Blue</P
></DD
><DT
>OSPF</DT
><DD
><P
>Black on Cyan</P
></DD
><DT
>IGRP</DT
><DD
><P
>Bright white on Cyan</P
></DD
><DT
>IGP</DT
><DD
><P
>Red on Cyan</P
></DD
><DT
>IGMP</DT
><DD
><P
>Bright green on Blue</P
></DD
><DT
>GRE</DT
><DD
><P
>Blue on white</P
></DD
><DT
>ARP</DT
><DD
><P
>Bright white on Red</P
></DD
><DT
>RARP</DT
><DD
><P
>Bright white on Red</P
></DD
><DT
>Other IP</DT
><DD
><P
>Yellow on red</P
></DD
><DT
>Non-IP</DT
><DD
><P
>Yellow on Red</P
></DD
></DL
></DIV
><P
> The lower window can hold up to 512 entries. You can
scroll the lower window by using the W key to move the Active indicator
to it, and by using the Up and Down cursor keys. The lower
window automatically scrolls every time a new entry is added, and either
the first entry or last entry is visible. Upon reaching 512 entries, old
entries are thrown out as new entries are added.</P
><P
> Some entries may be too long to completely fit in a screen line. You can
use the Left and Right cursor keys to vertically scroll the lower window
when it is marked <TT
CLASS="COMPUTEROUTPUT"
>Active</TT
>.</P
><P
> Entries for packets received on LAN interfaces also include the
source MAC address of the LAN host which delivered it. This behavior
is enabled by turning on the Source MAC addrs in traffic monitor toggle
in the <I
CLASS="EMPHASIS"
><A
HREF="config.html"
>Configure...</A
></I
> menu.</P
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN806"
>Entry Details</A
></H2
><P
> In general, the entries in the lower window indicate the protocol, the
IP datagram size (full frame size for non-IP, including ARP and
RARP), the source address, the destination
address, and the network interface the packet was detected on.
However, some protocols have a little more information.</P
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN809"
>ICMP</A
></H3
><P
> ICMP entries are displayed in this format:</P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
WIDTH="100%"
><TR
><TD
><PRE
CLASS="SYNOPSIS"
>ICMP <TT
CLASS="REPLACEABLE"
><I
>type</I
></TT
> [(<TT
CLASS="REPLACEABLE"
><I
>subtype</I
></TT
>)] (<TT
CLASS="REPLACEABLE"
><I
>size</I
></TT
> bytes) from <TT
CLASS="REPLACEABLE"
><I
>source</I
></TT
> to <TT
CLASS="REPLACEABLE"
><I
>destination</I
></TT
>
[(src HWaddr <TT
CLASS="REPLACEABLE"
><I
>srcMACaddress</I
></TT
>)] on <TT
CLASS="REPLACEABLE"
><I
>interface</I
></TT
></PRE
></TD
></TR
></TABLE
><P
> where type could be any of the following:</P
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><TT
CLASS="COMPUTEROUTPUT"
>echo req, echo rply</TT
></DT
><DD
><P
> ICMP echo request and reply. Usually used by the ping program and other network monitoring and diagnostic program. </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>dest unrch</TT
></DT
><DD
><P
> ICMP destination unreachable. Something failed to reach its target. The dest unreach type is supplemented with a further indicator of the problem. Destination unreachable messages for TCP traffic causes the corresponding TCP entry in the upper
window to be made available for reuse by new connections. </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>redirct</TT
></DT
><DD
><P
> ICMP redirect. Usually generated by a router to tell a host that a better gateway is available. </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>src qnch</TT
></DT
><DD
><P
> The ICMP source quench is used to stop a host from transmitting. It's a
flow control mechanism for IP. </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>time excd</TT
></DT
><DD
><P
> Indicates a packet's time-to-live value expired before it got
to its destination. Mostly happens if a destination is too far away.
Also used by the traceroute program.</P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>router adv</TT
></DT
><DD
><P
> ICMP router advertisement </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>router sol</TT
></DT
><DD
><P
> ICMP router solicitation </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>timestmp req</TT
></DT
><DD
><P
> ICMP timestamp request</P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>timestmp rep</TT
></DT
><DD
><P
> ICMP timestamp reply </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>info req</TT
></DT
><DD
><P
> ICMP information request </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>info rep</TT
></DT
><DD
><P
> ICMP information reply </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>addr mask req</TT
></DT
><DD
><P
> ICMP address mask request </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>addr mask rep</TT
></DT
><DD
><P
> ICMP address mask reply </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>param prob</TT
></DT
><DD
><P
> ICMP parameter problem </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>bad/unknown</TT
></DT
><DD
><P
> An unrecognized ICMP packet was received, or the packet is corrupted.</P
></DD
></DL
></DIV
><P
> The destination unreachable message also includes information on the
type of error encountered. Here are the destination unreachable codes:</P
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><TT
CLASS="COMPUTEROUTPUT"
>ntwk</TT
></DT
><DD
><P
> network unreachable </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>host</TT
></DT
><DD
><P
> host unreachable </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>proto</TT
></DT
><DD
><P
> protocol unreachable </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>port</TT
></DT
><DD
><P
> port unreachable </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>pkt fltrd</TT
></DT
><DD
><P
> packet filtered (normally by an access rule on a router or firewall) </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>DF set</TT
></DT
><DD
><P
> the packet has to be fragmented somewhere, but its don't fragment
(DF) bit is set.</P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>src rte fail</TT
></DT
><DD
><P
> source route failed </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>src isltd</TT
></DT
><DD
><P
> source isolated (obsolete) </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>net comm denied</TT
></DT
><DD
><P
> network communication denied </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>host comm denied</TT
></DT
><DD
><P
> host communication denied </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>net unrch for TOS</TT
></DT
><DD
><P
> network unreachable for specified IP type-of-service </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>host unrch for TOS</TT
></DT
><DD
><P
> host unreachable for specified IP type-of-service </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>prec violtn</TT
></DT
><DD
><P
> precedence violation </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>prec cutoff</TT
></DT
><DD
><P
> precedence cutoff </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>dest net unkn</TT
></DT
><DD
><P
> destination network unknown </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>dest host unkn</TT
></DT
><DD
><P
> destination network unknown</P
></DD
></DL
></DIV
><P
> For more information on ICMP, see RFC 792.</P
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN980"
>OSPF</A
></H3
><P
>OSPF messages also include a little more information. The format of an
OSPF message in the window is:</P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
WIDTH="100%"
><TR
><TD
><PRE
CLASS="SYNOPSIS"
>OSPF <TT
CLASS="REPLACEABLE"
><I
>type</I
></TT
> (a=<TT
CLASS="REPLACEABLE"
><I
>area</I
></TT
> r=<TT
CLASS="REPLACEABLE"
><I
>router</I
></TT
>) (<TT
CLASS="REPLACEABLE"
><I
>size</I
></TT
>bytes) from <TT
CLASS="REPLACEABLE"
><I
>source</I
></TT
> to <TT
CLASS="REPLACEABLE"
><I
>destination</I
></TT
>
[(src HWaddr <TT
CLASS="REPLACEABLE"
><I
>srcMACaddress</I
></TT
>)] on <TT
CLASS="REPLACEABLE"
><I
>interface</I
></TT
></PRE
></TD
></TR
></TABLE
><P
> The type can be one of the following:</P
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><TT
CLASS="COMPUTEROUTPUT"
>hlo</TT
></DT
><DD
><P
> OSPF hello. Hello messages establish OSPF communications and keep routers informed of each other's presence. </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>DB desc</TT
></DT
><DD
><P
> OSPF Database Description </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>LSR</TT
></DT
><DD
><P
> OSPF Link State Request </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>LSU</TT
></DT
><DD
><P
> OSPF Link State Update. Messages indicating the states of the OSPF network links </P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>LSA</TT
></DT
><DD
><P
> OSPF Link State Acknowledgment</P
></DD
></DL
></DIV
><P
> The entries in parentheses:</P
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><TT
CLASS="COMPUTEROUTPUT"
>a=<TT
CLASS="REPLACEABLE"
><I
>area</I
></TT
></TT
></DT
><DD
><P
> The area number of the OSPF message</P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>r=<TT
CLASS="REPLACEABLE"
><I
>router</I
></TT
></TT
></DT
><DD
><P
> The IP address of the router that generated the message. It
is not necessarily the same as the source address
of the encapsulating IP packet.</P
></DD
></DL
></DIV
><P
> Many times, the destination addresses for OSPF packets are class D
multicast addresses in standard dotted decimal notation or (if reverse
lookup is enabled), hosts under the <TT
CLASS="COMPUTEROUTPUT"
>MCAST.NET</TT
> domain. Such multicast
addresses are defined as follows:</P
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><TT
CLASS="COMPUTEROUTPUT"
>224.0.0.5 (OSPF-ALL.MCAST.NET)</TT
></DT
><DD
><P
>OSPF all routers</P
></DD
><DT
><TT
CLASS="COMPUTEROUTPUT"
>224.0.0.6 (OSPF-DSIG.MCAST.NET)</TT
></DT
><DD
><P
>OSPF all designated routers</P
></DD
></DL
></DIV
><P
> See RFC 1247 for details on the OSPF protocol.</P
></DIV
></DIV
></DIV
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