Network Administration

Describe hostname resolution as it applies to storage applianceExplain the limitations of using a filer as a routerManage interface parameters on a storage applianceDescribe the physical interfaces used by the filerCreate virtual interfaces ( VIFS) used by the storage appliance

Objectives

/etc/hostsA DNS serverA NIS serverHostname Resolution

/etc/hoststis-coe-storage> rdfile /etc/hosts#Auto-generated by setup Sat Jun 3 15:33:33 IST 2006127.0.0.1 localhost10.201.65.27 tis-coe-storage tis-coe-storage-e0a# 0.0.0.0 tis-coe-storage-e0b172.172.172.11 tis-coe-storage-e0c155.155.155.2 tis-coe-storage-e0d0.0.0.0 mailhosttis-coe-storage>

Hostname Resolution

NIS Server

The NIS client service provides information on security-related parameters such as hosts, user passwords, user groups and netgroups on a network.

NIS enables to maintain host information, hence there is no need to update the /etc/hosts file on each storage appliance on the network.

The storage appliance can be a NIS client and can query NIS server for host information, but it cannot be a NIS server.

If NIS is to be used as primary method for host resolution, it should be specified ahead of other methods in /etc/nsswitch.conf file.Hostname Resolution using NIS

DNS matches domain names to IP address and enables to centrally maintain host information.DNS is configured using options and commandsTo make the configuration permanent, enter them in /etc/rc file.The information command dns info, displays the status of the DNS resolver,a list of DNS servers, the state of each DNS server, the default domain configured on the storage appliance.Options dns.domainname wipro_dns sets the DNS domain name to the wipro_dnsOptions dns.enable on enables DNSHostname Resolution using DNS

The /etc/nsswitch.conf file lists the order in which a storage appliance searches for a resolution

tis-coe-storage> rdfile /etc/nsswitch.conf#Auto-generated by setup Sat Jun 3 15:33:33 IST 2006hosts: files nis dnspasswd: files nis ldapnetgroup: files nis ldapgroup: files nis ldapshadow: files nistis-coe-storage>

Search Order for Resolution

Even though a storage appliance may have multiple network interfaces, it does not function as a router for other network hosts.It however routes its own packets.

To check the current routing table use netstat r command. The netstat command displays network-related data structuresNetstat -rdefault 10.201.65.1 UGS 5 101931 e0a10.201.65/24 link#3 UC 0 0 e0a10.201.65.1 0:11:5d:27:18:8a UHL 1 0 e0a10.201.65.19 0:3:ba:e2:fd:90 UHL 0 40 e0a10.201.65.21 0:3:ba:e2:de:ef UHL 0 0 e0a10.201.65.22 0:3:ba:e2:fd:8f UHL 0 11 e0atis-coe-storage 0:a0:98:3:9b:66 UHL 0 21827 lo10.201.65.255 ff:ff:ff:ff:ff:ff UHL 0 10812 e0a

Storage Appliance is not a router

Modifying the route tableRoute [-fn] add|delete [host|net] destination [gateway metric]

CommandResultRoute add default 10.10.10.1 1Add a default route through 10.10.10.1 with metric(hop) 1route add host client2 bldg_router 1Adds a router to client2 through bldg_router with a metric 1Route delete 193.20.8.173 193.20.4.254Deletes the route destination 193.20.8.173 connecting through 193.20.4.254

The filer supports these network typesEthernet 10/100Base-TGigabit Ethernet Jumbo frames supported in DATA ONTAP 6.x and later for filers with Gigabit Ethernet Controller II interface

Interface names are based on Network Type Slot Number Port Number, with Multiport interfaceInterface Names

Network interface configuration parametersIP addressNetmask and broadcast addressMediatype,speedMaximum transmission unit(MTU)Flow control(Gigabit Ethernet II controller only)Up or down state

Changes are not permanent until entered into the /etc/rc file

The ifconfig command

What is a VIF?Aggregate multiple Ethernet links into a single logical channel between 2 devicesUpto 16 Ethernet interfaces can be grouped into a single logical interfaceThe advantages include, higher throughput, fault tolerance,protection against a switch port becoming a single point of failureClients access a single virtual IP addressEtherchannel Trunks (Virtual Interfaces)

VIFs are also known as trunks,virtual aggregations,link aggregations, or etherchannel virtual interfaces.

Trunks can be single mode or multimode.

In a single mode trunk,one interface is active while the other interface is on standby.Failure signals the inactive interface to take over and maintain the connection with the switch.Single mode Trunk

In a multimode trunk, all interfaces are active providing greater speed when multiple hosts access the storage appliance.

The switch determines how the load is balanced among the interfaces and must therefore support manually configurable trunking.

Multi-mode Trunk

Load balancing is supported for multimode VIFs only.Load balancing ensures that all the interfaces of a multimode.There are 3 methods:IP-based(default) The outgoing interfaces selected based on the filer and client IP addressMAC-based The outgoing interface selected on the basis of the filer and clients MAC addressRound-Robin All the interfaces selected on a rotating basis

Load Balancing

vif create [single|multi] -b [rr|mac|ip] [] vif add vif delete vif destroy vif {favor|nofavor} vif status [] vif stat [interval]

The named virtual interface is treated as a single interface: ifconfig vif_nameVirtual interface commands

How does a storage appliance resolve hostnames?What are the limitations of using a storage appliance as a router?What does the ifconfig command display?What is virtual interface?

Topic Review