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Chapter 9
Troubleshooting Novell Connectivity
all applicable frame types, and it adds a great deal of unnecessary overhead
for both the server and the network. It is recommended that administrators
select one frame type for new installations and remove as many frame types
as possible in legacy installations.
Although the default protocol for NetWare 5.0 is IP, the IPX default
(when used) is Ethernet 802.2, and 802.2 has been the default since Net-
Ware 3.12. Prior to version 3.12, Novell used Ethernet 802.3, or raw Ether-
net. This frame type supports only IPX, and places a length field after the
source MAC address in an Ethernet frame. As noted in Table 9.1, the selec-
tion of frame type is dependent on existing network applications and con-
figurations, as well as on the features needed.
IPX external network numbers must be unique for each frame type used, even
if two frame types are bound to the same physical network.
Get Nearest Server
Before connecting to a Novell server, clients must locate an appropriate
resource. This is accomplished with the
GNS (get nearest server)
request that
is specified within the SAP. The next section addresses the SAP process spe-
cifically, whereas the focus of this section is the GNS process itself.
GNS is a broadcast datagram that is answered by any IPX server on the
network. If there are multiple servers on a network segment, the client
receives a response from each one and accepts the first one for the rest of the
initialization process. Note that the first server may not be the preferred
server listed in the client's configuration file.
When a client wishes to connect to a network resource, it uses the GNS
broadcast, which is captured with an EtherPeek analyzer, as follows. In this
example, the workstation's MAC address is
00:60:08:9e:2e:44
and the
first packet is the client's GNS request.
Flags: 0x80
802.3
Status: 0x00
Packet Length:64
Timestamp: 22:56:14.565643 10/07/1998
802.3 Header
Destination:
ff:ff:ff:ff:ff:ff Ethernet Brdcast
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