Saturday, July 4, 2009

Network Configuration Overview

1. Local Files Mode - config is defined statically via key files
2. Network Client Mode - DHCP is used to auto-config interface(s)

Current Dell PE server has 3 NICs:
1. e1000g0 - plumbed (configured for network client mode)
2. iprb0 - unplumbed
3. iprb1 - unplumbed

1-Virtual Mandatory interface lo0 - loopback

Determine physical interfaces using 'dladm show-dev | show-link'
Determine plumbed and loopback interfaces using 'ifconfig -a'

NIC naming within Solaris OS: i.e. e1000g0 - e1000g(driver name) 0(instance)

Layers 2 & 3 info. - ifconfig -a, or ifconfig e1000g0
Layer 1 info. - dladm show-dev | show-link

###Key network configuration files###
svcs -a | grep physical
svcs -a | grep loopback

1. IP Address - /etc/hostname.e1000g0, /etc/hostname.iprb0 | iprb1
2. Domain name - /etc/defaultdomain - linuxcbt.internal
3. Netmask - /etc/inet/netmasks -
4. Hosts database - /etc/hosts, /etc/inet/hosts - loopback & ALL interfaces
5. Client DNS resolver file - /etc/resolv.conf
6. Default Gateway - /etc/defaultrouter -,,
7. Node name - /etc/nodename
Name service configuration file - /etc/nsswitch.conf

netstat -D - returns DHCP configuration for ALL interfaces
ifconfig -a - returns configuration for ALL interfaces

Reboot system after transitioning from network client(DHCP) mode to local files(Static) mode

mv dhcp.e1000g0 to some other name or remove the file so that the DHCP agent is NOT invoked
echo "linuxcbtsun1" > /etc/nodename

###Plumb/enable the iprb0 100Mb/s interface###
Plumbing interfaces is analagous to enabling interfaces
Note: is a Linux host waiting to communicate with iprb0 interface
1. ifconfig iprb0 plumb up - this will enable iprb0 interface
2. ifconfig iprb0 netmask - this will enable layer-3 IPv4 address

Steps to UNplumb an interface:
1. ifconfig iprb0 unplumb down

###Ensure that newly-plumbed interface settings persists across reboots###
Steps include updating/creating the following files:
1. echo "" > /etc/hostname.iprb0
2. create entry in /etc/hosts - linuxcbtsun1
3. echo "" >> /etc/inet/netmasks

Note: To down interface, execute:
ifconfig interface_name down
ifconfig iprb0 down && ifconfig iprb0

###Sub-interfaces/Logical Interfaces###
e1000g0(physical interface) - Apache website) Apache website) for SSH)

iprb0 -

Use 'ifconfig interface_name addif ip_address '
ifconfig e1000g0 addif (RFC-1918 - defaults /24)

Note: This will automatically create an 'e1000g0:1' logical interface
Note: Solaris places new logical interface in DOWN mode by default
Note: use 'ifconfig e1000g0:1 up' to bring the interface up

Note: logical/sub-interfaces are contingent upon physical interfaces
Note: if physical interface is down, so will the logical interface(s)
Note: connections are sourced using IP address of physical interface

###Save logical/sub-interface configuration for persistence across reboots###

1. gedit /etc/hostname.e1000g0:1 -
2. gedit /etc/hostname.e1000g0:2 -
3. Optionally update /etc/hosts - /etc/inet/hosts
4. Optionally update /etc/inet/netmasks - when subnetting

Note: To remove logical interface execute the following:
ifconfig physical_interface_name removeif ip_address
ifconfig iprb0 removeif

###/etc/nsswitch.conf - name service configuration information ###
functions as a policy/rules file for various resolution:
1. DNS
2. passwd(/etc/passwd,/etc/shadow),group(/etc/group)
3. protocols(/etc/inet/protocols)
4. ethers or mac-to-IP mappings
5. hosts - where to look for hostname resolution: files(/etc/hosts) dns(/etc/resolv.conf)

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