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July 2011

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Subject:
Re: virtual network
From:
Todd And Margo Chester <[log in to unmask]>
Reply To:
Todd And Margo Chester <[log in to unmask]>
Date:
Fri, 15 Jul 2011 16:53:53 -0700
Content-Type:
text/plain
Parts/Attachments:
text/plain (188 lines) 
> On 07/13/2011 11:08 AM, Todd And Margo Chester wrote:

>> On 07/12/2011 06:36 PM, Yasha Karant wrote:

>>> I attempted to add the virtual network interface you suggested with

>>> simply the ifcfg-eth0.5 script you provided; however, the system would

>>> not generate it. I then found a reference to a command vconfig that I

>>> used (please see below) that did work and created a eth0.5 after ifup

>>> using your script. However, this caused the machine not be visible on

>>> the physical network -- netstat -r did not find default. I tried ping,

>>> etc. A reboot with the ifcfg-eth0.5 script moved to my home directory

>>> (so that it would not be used but not lost) resulted in a working

>>> Internet connection, but no eth0.5 .

>>>

>>> Any further suggestion?

>>>

>>> Thanks,

>>>

>>> Yasha Karant

>>>

>>> [root@jb344 network-scripts]# vconfig add eth0 5

>>> WARNING: Could not open /proc/net/vlan/config. Maybe you need to load

>>> the 8021q module, or maybe you are not using PROCFS??

>>> Added VLAN with VID == 5 to IF -:eth0:-

>>> [root@jb344 network-scripts]# ./ifup eth0.5

>>> [root@jb344 network-scripts]# ifconfig -a

>>> eth0 Link encap:Ethernet HWaddr 6C:62:6D:B3:EB:04

>>> inet addr:139.182.151.44 Bcast:139.182.255.255 Mask:255.255.255.0

>>> inet6 addr: fe80::6e62:6dff:feb3:eb04/64 Scope:Link

>>> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1

>>> RX packets:7740 errors:0 dropped:15 overruns:0 frame:0

>>> TX packets:7745 errors:0 dropped:0 overruns:0 carrier:0

>>> collisions:0 txqueuelen:1000

>>> RX bytes:5712610 (5.4 MiB) TX bytes:1292931 (1.2 MiB)

>>> Interrupt:50 Base address:0x6000

>>>

>>> eth0.5 Link encap:Ethernet HWaddr 6C:62:6D:B3:EB:04

>>> inet addr:192.168.254.10 Bcast:192.168.254.255 Mask:255.255.255.0

>>> inet6 addr: fe80::6e62:6dff:feb3:eb04/64 Scope:Link

>>> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1

>>> RX packets:0 errors:0 dropped:0 overruns:0 frame:0

>>> TX packets:79 errors:0 dropped:0 overruns:0 carrier:0

>>> collisions:0 txqueuelen:0

>>> RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)

>>>

>>>

>>> ifcfg-eth0.5

>>>

>>> DEVICE=eth0.5

>>> BOOTPROTO=none

>>> BROADCAST=192.168.254.255

>>> IPADDR=192.168.254.10

>>> NETMASK=255.255.255.0

>>> NETWORK=192.168.254.0

>>> GATEWAY=192.168.254.10

>>> ONBOOT=yes

>>> USERCTL=yes

>>> IPV6INIT=no

>>> PEERDNS=no

>>> PROMISC=yes

>>> # TYPE=Ethernet

>>> VLAN=YES

>>> NAME=vbox-bridged

>>>

>>>

>>>

>>>

>>>

>>

>> Yasha,

>>

>> This is the article I originally used to create my VLANs:

>> http://www.cyberciti.biz/tips/howto-configure-linux-virtual-local-area-network-vlan.html 

>>

>>

>>

>> I am not find anything I missed. But, it is much better written

>> than my stuff, so it should be worth reviewing. If you find something

>> I missed, please let me know.

>>

>> -T

>



On 07/12/2011 06:36 PM, Yasha Karant wrote:

> I attempted to add the virtual network interface you suggested with 

> simply the ifcfg-eth0.5 script you provided; however, the system would 

> not generate it.  I then found a reference to a command vconfig that I 

> used (please see below) that did work and created a eth0.5 after ifup 

> using your script.  However, this caused the machine not be visible on 

> the physical network -- netstat -r did not find default.  I tried 

> ping, etc.  A reboot with the ifcfg-eth0.5 script moved to my home 

> directory (so that it would not be used but not lost) resulted in a 

> working Internet connection, but no eth0.5 .

>

> Any further suggestion?

>

> Thanks,

>

> Yasha Karant





On 07/13/2011 11:56 AM, Yasha Karant wrote:

> I need to do some further digging -- the problem may be with the LAN 

> at my university.

>

> I used the same article as a reference.

>

> At my university, although we have a Class B IPv4 address space, we 

> internally use CIDR and all IEEE 802.3 connections (nominally 100 

> BaseT and gigabit) require hard IPv4 addresses (eventually, there will 

> be internal IPv6 support).  The university also supports 802.11 with 

> DHCP.  Moreover, there is 802.3 MAC layer address monitoring; if a 

> 802.3 connection is authorized for only one MAC layer addresses and 

> more than one appears, the 802.3 connection is disabled.  Thus, we 

> cannot use simple 802.3 repeaters or even switches to increase the 

> number of 802.3 NICs connected.   The only exception is in our 

> research laboratories over which we have control of the MAC address 

> space as well as our own DNS (in /24 size blocks) and can (and do) run 

> our own MAC and IP layer switches and routers. But our Faculty and 

> administrative offices (such as the office with my faculty 

> workstation) and our instructional laboratories have the restrictions 

> I mentioned above.    The only workaround that we have found, as used 

> by one of my colleagues, is to install two NICs (in his case 802.3) in 

> one machine -- one NIC is visible to the campus LAN, and the other 

> provides via a relay hidden from the campus LAN (software on the dual 

> NIC workstation) a connection for all other wired LAN units that he 

> uses.  I suspect that somehow the virtual NIC that was created by the 

> process listed below became "visible" to the campus LAN resulting in 

> loss of the default route gateway, although the 802.3 MAC layer was 

> still operational.

>

> Yasha Karant



Hi Yasha,



I am confused as to what is going on.  Here is my exact configuration.

Maybe you will find a clue in it.



-T





# ifconfig eth0.5

eth0.5    Link encap:Ethernet  HWaddr 00:25:90:20:3B:2A

           inet addr:192.168.254.10  Bcast:192.168.254.255  

Mask:255.255.255.0

           inet6 addr: fe80::225:90ff:fe20:3b2a/64 Scope:Link

           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

           RX packets:0 errors:0 dropped:0 overruns:0 frame:0

           TX packets:0 errors:0 dropped:12 overruns:0 carrier:0

           collisions:0 txqueuelen:0

           RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)





# netstat -rn

Kernel IP routing table

Destination     Gateway         Genmask         Flags   MSS Window  irtt 

Iface

192.168.1.0     0.0.0.0         255.255.255.0   U         0 0          0 

eth1

192.168.254.0   0.0.0.0         255.255.255.0   U         0 0          0 

eth0.5

192.168.255.0   0.0.0.0         255.255.255.0   U         0 0          0 

eth0

169.254.0.0     0.0.0.0         255.255.0.0     U         0 0          0 

eth0

169.254.0.0     0.0.0.0         255.255.0.0     U         0 0          0 

eth1

169.254.0.0     0.0.0.0         255.255.0.0     U         0 0          0 

eth0.5

0.0.0.0         192.168.1.1     0.0.0.0         UG        0 0          0 

eth1







# more /etc/sysconfig/network-scripts/ifcfg-eth0.5

DEVICE=eth0.5

BOOTPROTO=none

BROADCAST=192.168.254.255

IPADDR=192.168.254.10

NETMASK=255.255.255.0

NETWORK=192.168.254.0

GATEWAY=192.168.254.10

ONBOOT=yes

USERCTL=yes

IPV6INIT=no

PEERDNS=no

PROMISC=yes

TYPE=Ethernet

VLAN=yes

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