Introducing Route Table Search Order
The kernel routing algorithm searches route table entries in the following 1. The kernel routing algorithm checks the LAN for destination hosts. The kernel extracts the destination IP address from the IP datagram and computes the destination network number. The destination network number is then compared with the network numbers of all of the local interfaces interfaces that are physically attached to the system for a match. If the destination network number matches that of a local interface...
Setting a Local Ethernet Address
In today's network environments, many systems have multiple interfaces, often on the same subnet or collision domain. Because an Ethernet address targets systems, each interface on the same network or subnet on a multi-interface system must have a unique Ethernet address. Sun network adapters have local Ethernet addresses encoded in their programmable read-only memories PROMs . To view the current host-based Ethernet address, perform the command at the ok prompt Sun Ultra 5 10 UPA PCI...
Operation of CIDR
CIDR uses classless addresses in that it uses netmasks that are referred to as network prefixes to create varying network sizes. The network prefix is expressed in the following notation X.X.X.X 18, which is equivalent to the netmask of 255.255.192.0. The first 18 bits identify the network, and the remaining 14 bits identify the host. Figure 7-10 shows an example of a CIDR prefix. This use of netmasks means addresses can be supernetted as well as subnetted. Supernetting is the combining of two...
NameResolution Process
DNS name resolution is the process of translating a domain name to an IP address or translating an IP address to a domain name. Name resolution begins with client-side resolver code. Resolver code is built into the operating system libraries and is available to programs that use system interface calls. Does not cache any information Queries the DNS servers that are specified in the etc resolv.conf file Is activated by a reference to DNS in the etc nsswitch.conf file hosts entry A DNS client...
Info Bbb
3bbcd9ef 3bbcd9ef 3bbcd9ef 3bbcd9ef 3bbcd9ef Datagram received on network device qfe0 0108002090B5C7,192.168.1.14 currently marked as unusable. select_offer hostname request for dhcp-hostname-test name_avail T gethostbyname_r failed select_offer name_avail false or no address for dhcp-hostname-test 3bbcd9ef 3bbcd9f0 3bbcd9f0 3bbcd9f0 3bbcd9f2 3bbcd9f2 found CD 3bbcd9f2 3bbcd9f2 found CD 3bbcd9f2 3bbcd9f2 3bbcd9f2 3bbcd9f2 Reserved offer 192.168.1.13 Unicasting datagram to 192.168.1.13 address....
sys11 ifconfig qfe0
qfe0 mtu 1500 index 3 inet 192.168.1.1 netmask ffffff00 broadcast 192.168.1.255 groupname mpgrp-one ether 8 0 20 ac 9b 20 If the interface is up, examine the inet IP address , netmask, and broadcast entries, and make sure that they are set correctly. If the IP address is set incorrectly, check the contents of the etc inet hosts file. If the netmask and broadcast addresses are wrong, check the contents of the etc inet netmasks file. The correct device and file name are defined for the interface....
sys13 ifconfig iptunO inet6 tsrc 1921681113 tdst 1921682223 up
5. View the interface's configuration on the sys13 system. Notice how the MTU for the ip.tun0 interface has been lowered from 1500 to 1480. This is because the largest IPv6 fragment must still accommodate the IPv4 header that is to be appended to the IPv6 fragment encapsulation . inet 127.0.0.1 netmask ff000000 qfe0 mtu 1500 index 2 inet 192.168.1.3 netmask ffffff00 broadcast 192.168.1.255 groupname mpgrp6-one ether 8 0 20 b7 4e 5c qfe0 1 mtu 1500 index 2 inet 192.168.1.113 netmask ffffff00...
Network Interface Layer
Figure 1-2 shows the Network Interface layer. The primary functions of this layer are Managing the delivery of data across the physical network Figure 1-2 TCP IP Network Interface Layer The Network Interface layer services the Internet layer by providing communication between nodes on the same network. This layer defines how bits are assembled into manageable units of data. A packet data unit PDU is a series of bits with a well-defined beginning and a well-defined end. Figure 1-3 shows a...