Network Physical Connectivity Check for Solaris and Linux

Network connectivity checks For the server without OS  ( just Racked hardware and powered up)

 

For X86 Hardware

We have to make LED checks – like when we disconnect the cable at the server side / switch side the Link / Act LEDs should lit up on powered on machines.

For Sparc based Servers:

We can watch individual interfaces to see if they have a connection and can ‘see’ the network. At the OBP prompt on the client, use the “watch-net-all” command to test and see the network devices.

 

 

Example  :

ok> watch-net-all
/pci@7c0/pci@0/network@4,1
1000 Mbps full duplex  Link up
Looking for Ethernet Packets.
‘.’ is a Good Packet.  ‘X’ is a Bad Packet.
Type any key to stop.
………………………………………….
/pci@7c0/pci@0/network@4
Timed out waiting for Autonegotiation to complete
Check cable and try again
Link Down
/pci@7c0/pci@0/pci@8/network@1,1
Timed out waiting for Autonegotiation to complete
Check cable and try again
Link Down
/pci@7c0/pci@0/pci@8/network@1
Timed out waiting for Autonegotiation to complete
Check cable and try again
Link Down
ok>

From the above output you can notice that  /pci@7c0/pci@0/network@4,1 is shown with network connectivity. All other ports are not connected to the network.

Network Checks for the Hosts running with Solaris or Linux

Use the system-appropriate commands to watch the interface, to ensure that packets are being seen on the network.

Examples include:

Linux  ( X86 ) 

# ethtool eth0

Settings for eth0:
Supported ports: [ MII ]
Supported link modes:   10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Supports auto-negotiation: Yes
Advertised link modes:  10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Advertised auto-negotiation: Yes
Speed: 100Mb/s
Duplex: Full
Port: Twisted Pair
PHYAD: 1
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: g
Wake-on: d
Current message level: 0x000000ff (255)
Link detected: yes

Ping the the system from a other host of same network in one session  and  then watch the IP traffic on the X64 system with tcpdump in another session.

A successful ping has a request and a reply.  Iphost  option used to filter the specific host related network data, otherwise tcpdump will flood the console.

# tcpdump -i eth0 -n ip host 10.16.8.63

tccpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes
16:34:53.133085 IP 10.16.8.21 > 10.16.8.63: ICMP echo request, id 13641, seq 0, length 64
16:34:53.133250 IP 10.16.8.63 > 10.16.8.21: ICMP echo reply, id 13641, seq 0, length 64

Solaris Operating System

Using  snoop 

# /usr/sbin/snoop -d eth0 -o  network.log

The above example will find the network traffic on eth0 and sends the output to a file network.log in the current directory. You have to terminate the command manually with   “ ^C  “ otherwise it will keep an adding info to the file. And later you can view the file output with the below command

#  /usr/sbin/snoop -i snoop.out  -D |grep –v “drops: 0”

And “–D” option displays about the number of packet drops, and with above command you can easily figure out that “if all the packets from the interface dropping, then there is a patch issue” .  Once physical connectivity has been established, the interface can be observed for errors.

Solaris Operating System provides the kstat interface for this type of monitoring.

For example, to watch hme0’s interface statistics, on an hme interface, one would use the following:

# kstat -m hme0 -i 0 5

and monitor statistics such as collisions, alignment errors. If these error counters are increasing on a switched network, it would indicate that further investigation is warranted. The most likely cause of such issues would be a bad cable, or incorrect switch settings. Replace the cable, ensure the switch is set to auto-negotiate and re-test.

 

Cable tester

A cable tester is one of the quickest and easiest ways to check a cable, and it’s connections through patch boards to the target switch. If one is available, connect the tester to each end of the cable, and verify that the cable has connectivity through all 8 pins. Normally Datacenter Operations team will have these devices.

If you don’t have one then you should go through the traditional approach, to verify from server end.

Ramdev

Ramdev

I have started unixadminschool.com ( aka gurkulindia.com) in 2009 as my own personal reference blog, and later sometime i have realized that my leanings might be helpful for other unixadmins if I manage my knowledge-base in more user friendly format. And the result is today's' unixadminschool.com. You can connect me at - https://www.linkedin.com/in/unixadminschool/

14 Responses

  1. Yogesh Raheja says:

    @All, ndd / kstat / dladm are traditional solaris commands (ndd,dladm only solaris 10) and (kstat solaris 10 and prior), netstat, arp, rarp, snoop, tcpdump most commonly used in Interface/network connectivity issue. Most importantly in Solaris 11, ndd and kstat are going to replaced by a new robost networking model using “IPADM” set of commmands. Its will replace the traditional thinking with very new and robost networking model.
    :)

  2. ramdev says:

    Thanks to you all for your good points

  3. Vignesh says:

    I have 4yrs of experience in Solaris,vcs & vxvm. Now i’m looking for study / prepare another unix favoured OS. Anyone can suggest, future and presently best unix OS.

  4. Yogesh Raheja says:

    @Vignesh, I personally suggest you to go with Linux. Solaris + Linux is a very good combination. In today’s industry you will find Linux with every customer to reduce cost for NON-prod. environments. moreover as per industry survey Linux will be in boom for many years from Now.

  5. Vignesh says:

    Thanks for your suggestion and supporting us with great Gurukulindia.com

  6. Yogesh Raheja says:

    @Vignesh, you are always welcome and many thanks for your trust in us.

  7. Santhu says:

    Hi can anyone say how find the NIc cards in solaris 9 on a x86 machine??

  8. Santhu says:

    Un configured NIC cards?

  9. santhu says:

    Hi can anyone say how find thelist of unconfigured NIC cards in solaris 9 on a x86 machine??

    • Ramdev Ramdev says:

      Santhu, I would use “ifconfig -a plumb” , whenever i don’t know the names of unused interfaces. It won’t disturb the existing interfaces but enable all other unconfigured ones. you can later unplumb whatever you don’t want.

  10. santhu says:

    Thanx for ur response

  1. September 16, 2015

    […] Read – Verifying Physical Connectivity for Solaris and Linux […]

  2. September 17, 2015

    […] Read – Verifying Physical Connectivity for Solaris and Linux […]

  3. September 18, 2015

    […] Read – Network Physical Connectivity Check for Solaris and Linux […]

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