Test Network Configuration: Difference between revisions

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===Questions===
===Questions===


*Is the XO connected to [[Under_a_Tree|local-link]] or a mesh?
* Is the XO connected to [[Under_a_Tree|Link-local]] or a mesh?
*Is it connected to an [[One_Laptop_acting_as_MPP|MPP]]?
* Is it connected to an [[One_Laptop_acting_as_MPP|MPP]]? ''(Depreciated; no longer available)''
*Is it connected to the internet?
* Is it connected to the Internet?
*Is it connected to a jabber server?
* Is it connected to a Jabber ([[wikipedia:Extensible Messaging and Presence Protocol|XMPP]]) server?
*What is the ip?
* What is the IP address?


===Layer 2===
===Layer 2===


The wireless configuration of the network can be examined using the <code>iwconfig eth0</code> command. We get MAC layer information such as
The wireless configuration of the network can be examined using the <code>iwconfig eth0</code> command. We get MAC layer information such as
#ESSID
# ESSID
#*olpc-mesh : Indicates a mesh with or without internet connectivity
#* olpc-mesh : Indicates a mesh with or without Internet connectivity
#Mode
# Mode
#*Managed : It is an Access Point(AP) configuration
#* Managed : It is an Access Point(AP) configuration
#*Ad-hoc : It is a mesh configuration(no infrastracture)
#* Ad-hoc : It is a mesh configuration (no infrastructure)
#Frequency
# Frequency (MHz)
#*2.412 : Channel 1
#* 2.412 : Channel 1
#*2.437 : Channel 6
#* 2.437 : Channel 6
#*2.462 : Channel 11
#* 2.462 : Channel 11
#*Channels 1,6,11 can be used to join a link-local mesh
#* Channels 1,6, 11 can be used to join a Link-local mesh
#*Channels 1, 6, 11 can also be a Schoolserver mesh (ch 1 is almost always on at OLPC offices)
#* Channels 1, 6, 11 can also be a School server mesh (ch 1 is almost always on at OLPC offices)
#*At OLPC offices, '802.11 Media lab' AP operates on Channels 6 and 11
#* At OLPC offices, '802.11 Media lab' AP operates on Channels 6 and 11
#Cell/AP Mac
# Cell/AP Mac
#*Access Point : The AP's MAC
#* Access Point : The AP's MAC
#*Cell : A virtual 02:xx:xx:... MAC address assigned by the some mesh points. It indicates mesh configuration
#* Cell : A virtual 02:xx:xx:... MAC address assigned by the some mesh points. It indicates mesh configuration


===Layer 3===
===Layer 3===
====IP addresses====
====IP addresses====
The network layer information can be observed with <code>ifconfig</code>. The <code>eth0</code> part gives an IPv4 address only if the XO is connected directly to an AP. The address can also indicate a private network. Media lab gives an 18.85.x.x address. The <code>msh0</code> gives
The network layer information can be observed with <code>ifconfig</code>. The default built-in wireless adapter provides an Ethernet interface <code>eth0</code>, and a mesh interface <code>msh0</code>. Connecting additional 802.11s adapters will introduce additional pairs of <code>eth1,eth2,..</code> and <code>msh1,msh2,..</code> interfaces. Connecting Ethernet adapters will introduce additional <code>eth1,eth2,..</code> interfaces, and will provide Ethernet connectivity. In the default case(although the same applies for all) the interfaces provide the following IPv4 addresses
* <code>eth0</code>
#when connected to an AP
*# Connected to an AP without NAT
#*192.168.x.x (typical IP, if the AP is providing dhcp)
#*10.x.x.x (connected to '802.11 media lab' AP at olpc)
*#* any public address(18.85.x.x when connected to Media Lab 802.11 at OLPC offices)
#when connected to the olpc school server mesh
*# Connected to an AP, but behind a NAT
*#* 192.168.x.x
#*172.x.x.x(the current school server in the lab)
*#* 172.x.x.x
#when connected in local link
#*169.254.x.x
*#* 10.x.x.x
*# Connected to a switch with no gateway
*#* 169.254.x.x
*# Not connected to an AP
*#* blank
* <code>msh0</code>
*# Link-local
*#* 169.254.x.x
*# Connected to an MPP
*#* 169.254.x.x
*# Connected to a School server
*#* 172.x.x.x (172.18.x.x when connected to the School server in OLPC offices)
*#* 192.168.x.x
*#* 10.x.x.x
*# Connected to an AP via wireless or Ethernet adapter
*#* 169.254.x.x
*#* none
It is interesting to note that the 169.254.x.x address when applicable are always the same by default. If no address shows in the <code>msh0</code> you can
killall dhclient
dhclient # Send DHCP request to force (if possible) to acquire a connection to a gateway
avahi-autoipd # If no mesh gateway is available (MPP or School server) it will assign a zeroconf address(169.254.x.x)


====DNS check====
====[[wikipedia:Domain Name System|DNS]] check====
The most direct way to check internet connectivity is by checking the <code>resolv.conf</code> file. It shows if the XO is registered to a DNS server. It can be viewed with
The most direct way to check Internet connectivity is by checking the <code>resolv.conf</code> file. It shows if the XO is registered to a DNS server. It can be viewed with,
cat /etc/resolv.conf
cat /etc/resolv.conf
# If it is empty,
*If it is empty there is generally no connection to the internet(technically, no connection to the DNS server)
#* No connection to the Internet (technically, no connection to the DNS server).
*If it includes a nameserver with 169.254.x.x address there is internet connectivity through an MPP. The address is in fact the IP of the XO which acts as an MPP
# If it includes a nameserver with private address (172.x.x.x, 169.168.x.x, 10.x.x.x),
*This is useful to determine on which MPP the XO is connected to, when there are multiple MPPs
#* Connected to an AP behind a NAT,
*The is a rare possibility resulting from a Network Manager failure, of an XO to have access to the internet, but the resolv.conf to be blank. In that case the XO will not be able to resolve hostnames. This possibility can be examined with
#* Connected to an MPP, which connects to an AP behind a NAT,
#* Connected to a School server (172.18.0.1 for the School server in OLPC offices, although others are also available).
# If it includes a nameserver with public address,
#* Connected to an AP without a NAT,
#* Connected to an MPP, which connects to an AP without a NAT.
# The is a rare possibility resulting from a NetworkManager failure, of an XO to have access to the Internet, but the resolv.conf to be blank. In that case, the XO will not be able to resolve hostnames. This possibility can be examined with,
ping www.mit.edu # No replies
ping www.mit.edu # No replies
ping 18.7.22.83 # Normal replies
ping 18.7.22.83 # Normal replies


The general rule of thumb regarding the resolv.conf file in the lab XOs is
The general rule of thumb regarding the resolv.conf file in the lab XOs is the following:
*empty: local-link
* empty: Link-local
*169.254.x.x: MPP
* 172.18.x.x: Schoolserver
*172.18.x.x: Schoolserver
* 18.85.x.x: Media lab AP
*18.85.x.x: Media lab AP


If the XO connects to a channel that includes a School server or an MPP, but for a reason there is no internet connectivity, and the <code>resolv.conf</code> file is empty check if it is [[Test_Config_Notes#Modify_the_Mesh_Discovery_Sequence|forced in link-local]] or other configuration
If the XO connects to a channel that includes a School server or an MPP, but for some reason there is no Internet connectivity, and the <code>resolv.conf</code> file is empty, check if it is [[Test_Config_Notes#Modify_the_Mesh_Discovery_Sequence|forced in Link-local]] or another configuration,
nano /etc/NetworkManager/mesh-start # confirm that the file is empty(if it exists)
nano /etc/NetworkManager/mesh-start # confirm that the file is empty(if it exists)
If the problem persists you can try
If the problem persists you can try,
killall dhclient
killall dhclient
dhclient # Send DHCP request to force(if possible) to acquire a routable IP
dhclient # Send DHCP request to force(if possible) to acquire a routable IP


===Telepathy services===
===Telepathy services===
The Presence Service acquires information on other XOs in the network, and provides the capability to view them in the neighborhood view, or share with them an activity. This is achieved through two child telepathy services, Salut and Gabble.
The Presence Service acquires information on other XOs in the network, and provides the capability to view them in the Neighborhood view, or share with them an activity. This is achieved through two child telepathy services, Salut and Gabble.


====Salut====
====Salut====
Salut runs when the XO is connected to a mesh. It uses the avahi _presence._tcp service. All XOs in the same mesh indentify themselves in the neighborhood view through Salut. They can be examined through
Salut runs when the XO is connected to a mesh. It uses the avahi _presence._tcp service. All XOs in the same mesh identify themselves in the Neighborhood view through Salut. They can be examined through,
avahi-browse -t _presence._tcp
avahi-browse -t _presence._tcp


====Gabble====
====Jabber====
Gabble will allow XOs that belong to different geographical locations to communicate with each other. It will detect internet connectivity and connect to a Jabber server. All XOs connected to the same jabber server will appear to the neighborhood view. The currently possible servers are
Gabble will allow XOs that belong to different geographical locations to communicate with each other. It will detect Internet connectivity and connect to a Jabber server. All XOs connected to the same Jabber server will appear to the Neighborhood view. The currently possible servers are
jabber.sugarlabs.org
jabber.laptop.org
jabber.laptop.org
olpc.collabora.co.uk
olpc.collabora.co.uk
*By build 616 the Presence Service does not allow Gabble and Salut to run simultaneously
* By build 616, the Presence Service does not allow Gabble and Salut to run simultaneously.
*It constantly checks whether there is internet connectivity, and switches from Salut to Gabble accordingly
* It constantly checks whether there is Internet connectivity, and switches from Salut to Gabble accordingly.
*The XOs displayed in the neighborhood view either belong to the mesh, or the Jabber server, not both
* The XOs displayed in the Neighborhood view either belong to the mesh, or the Jabber server, not both.
*The internet connectivity does not work very accurately. It is very common when connected to the School server, which provides connectivity, that the XO is running Salut. However, it is convenient in the sense that it can now share activities with others in the mesh.
* The Internet connectivity does not work very accurately. It is very common when connected to the School server, which provides connectivity, that the XO is running Salut. However, it is convenient in the sense that it can now share activities with others in the mesh.

====Detecting which service is running====
====Detecting which service is running====
*The simpler way to detect whether Salut or Gabble is running is by observing the neighborhood view. If you see XOs that you havent seen in the lab then you are probably running Gabble.
* The simpler way to detect whether Salut or Gabble is running is by observing the Neighborhood view. If you see XOs that you haven't seen in the lab, then you are probably running Gabble.
*It can also be checked from the Developer's Console - Presence tab - Buddies list - Handles column. The entries either start with <code>../gabble/jabber/..</code> or <code>../salut/local-xmpp/..</code>.
* It can also be checked from the [[Analyze]] Activity - Interfaces tab - Presence Service - Buddies list - Handles column. The entries either start with <code>../gabble/jabber/..</code> or <code>../salut/local-xmpp/..</code>.
*To confirm you are running Gabble you can check the <code>config</code> file for the <code>[Server]</code>(not Jabber) entry to be true. This, however, can be misleading, because the file doesnt update properly when you disconnect from the Jabber server. Thus, it usualy includes obsolete information.
* To confirm you are running Gabble you can check the <code>config</code> file for the <code>[Server]</code> (not Jabber) entry to be true. This, however, can be misleading, because the file doesn't update properly when you disconnect from the Jabber server. Thus, it usually includes obsolete information.
$ cat /home/olpc/.sugar/default/config
$ cat /home/olpc/.sugar/default/config
...
...
Line 83: Line 112:
registered = True # running Gabble
registered = True # running Gabble
server = jabber.laptop.org
server = jabber.laptop.org
*The console provides a more efficient way of determining with confidence which service is running. The process list will include either a <code>telepathy-salut</code> or a <code>telepathy-gabble</code> process
* The console provides a more efficient way of determining with confidence which service is running. The process list will include either a <code>telepathy-salut</code> or a <code>telepathy-gabble</code> process,
ps ax # general process list
ps ax # general process list
ps U olpc -f|grep telepathy # only the required entry will be displayed
ps U olpc -f|grep telepathy # only the required entry will be displayed
*Which Jabber server the XO is connected(if its running Gabble) get be examined using the <code>netstat</code> command
* The Jabber server to which the XO is connected (if it's running Gabble) can be examined using the <code>netstat</code> command,
netstat -tpT|grep telepathy # the connection established by the telepathy-gabble process
netstat -tpT|grep telepathy # the connection established by the telepathy-gabble process


===Combine the tests in an automated script===
===Combine the tests in an automated script===


All the above tests require checking many different locations and running several commands. Alternatively, you can execute this '''[http://wiki.laptop.org/images/8/8a/Status.sh status script]''', which will accumulate and display the following network overview directly
All the above tests require checking many different locations and running several commands. Alternatively, you may run <code>olpc-netstatus</code> from the [[Terminal Activity]] or a [[console]]. It will accumulate and display the following network overview directly. This is a case of an XO connected to the School server on Channel 1.

$bash status
$olpc-netstatus
nick : d01
mac : 00:17:c4:03:31:fb
ip eth0 : 18.85.18.23
Model : C2
ip msh0 : 169.254.7.84
Serial : CSN74400049
dns : 18.85.2.171
MAC : 00:17:C4:0C:CD:11
essid : media lab 802.11
Build : update.1 703
Firmware : CL1 Q2D14 Q2D
channel : 6
Libertas : 5.110.22.p1
telepathy : gabble
Nick : W03
jabber : jabber.laptop.org
Uptime : 01:12:06
config : Access point
IP eth0 : 172.18.0.250
IP msh0 : 169.254.5.77

DNS : 172.18.0.1
===Useful locations===
/etc/resolv.conf # DNS server
Telepathy : gabble
/etc/NetworkManager/mesh-start # used to force a lower priority network configuration
Jabber : schoolserver.laptop.org
XOs : 4
Essid : olpc-mesh
/home/olpc/.sugar/default/config # user information
Channel : 1
School : schoolserver.laptop.org
/home/olpc/.sugar/default/nm/networks.cfg # stores access points information
Config : School Mesh
/var/log/messages # main log file


More up-to-date version of olpc-netstatus, and other useful Network tools are available at [[Network Resources]].
===Useful Network and Mesh links===
[[Test_Config_Notes#Turn_on_MPP_Capability|Turn on MPP Capability]]


===Useful locations===
[[Test_Config_Notes#Testing_of_Different_Connection_Configurations|Testing of Different Connection Configurations]]
You may need to be [[root]] to access some of these files

; <tt>/etc/resolv.conf</tt>
[[Test_Config_Notes#Modify_the_Mesh_Discovery_Sequence|Modify the Mesh Discovery Sequence]]
: DNS server

; <tt> /etc/dhcpd.conf</tt>
[[Mesh_Forwarding_Table|Mesh Forwarding Table]]
: check whether the XO acts as an MPP

; <tt> /etc/NetworkManager/mesh-start</tt>
[[Wireless_Driver_README|Wireless Driver Readme]]
: used to force a lower priority network configuration

; <tt> /home/olpc/.sugar/default/config</tt>
[[Mesh_Network_Details|Mesh Network Details]]
: user information

; <tt> /home/olpc/.sugar/default/nm/networks.cfg</tt>
[[Mesh_Network_FAQ|Mesh Network FAQ]]
: stores access points information, such as WEP password

; <tt> /var/log/messages</tt>
[[Establishing_a_Mesh_Portal|Establishing a Mesh Portal]]
: main log file, may hold messages from NetworkManager

'''[http://www.cozybit.com/projects/mpp-utils Cozybit's MPP Utils]'''


[[Category:Preparing for testing]]
[[Category:Network]]
[[Category:Network]]
[[Category:OLPC FAQ]]

Latest revision as of 19:33, 27 April 2011

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Questions

  • Is the XO connected to Link-local or a mesh?
  • Is it connected to an MPP? (Depreciated; no longer available)
  • Is it connected to the Internet?
  • Is it connected to a Jabber (XMPP) server?
  • What is the IP address?

Layer 2

The wireless configuration of the network can be examined using the iwconfig eth0 command. We get MAC layer information such as

  1. ESSID
    • olpc-mesh : Indicates a mesh with or without Internet connectivity
  2. Mode
    • Managed : It is an Access Point(AP) configuration
    • Ad-hoc : It is a mesh configuration (no infrastructure)
  3. Frequency (MHz)
    • 2.412 : Channel 1
    • 2.437 : Channel 6
    • 2.462 : Channel 11
    • Channels 1,6, 11 can be used to join a Link-local mesh
    • Channels 1, 6, 11 can also be a School server mesh (ch 1 is almost always on at OLPC offices)
    • At OLPC offices, '802.11 Media lab' AP operates on Channels 6 and 11
  4. Cell/AP Mac
    • Access Point : The AP's MAC
    • Cell : A virtual 02:xx:xx:... MAC address assigned by the some mesh points. It indicates mesh configuration

Layer 3

IP addresses

The network layer information can be observed with ifconfig. The default built-in wireless adapter provides an Ethernet interface eth0, and a mesh interface msh0. Connecting additional 802.11s adapters will introduce additional pairs of eth1,eth2,.. and msh1,msh2,.. interfaces. Connecting Ethernet adapters will introduce additional eth1,eth2,.. interfaces, and will provide Ethernet connectivity. In the default case(although the same applies for all) the interfaces provide the following IPv4 addresses

  • eth0
    1. Connected to an AP without NAT
      • any public address(18.85.x.x when connected to Media Lab 802.11 at OLPC offices)
    2. Connected to an AP, but behind a NAT
      • 192.168.x.x
      • 172.x.x.x
      • 10.x.x.x
    3. Connected to a switch with no gateway
      • 169.254.x.x
    4. Not connected to an AP
      • blank
  • msh0
    1. Link-local
      • 169.254.x.x
    2. Connected to an MPP
      • 169.254.x.x
    3. Connected to a School server
      • 172.x.x.x (172.18.x.x when connected to the School server in OLPC offices)
      • 192.168.x.x
      • 10.x.x.x
    4. Connected to an AP via wireless or Ethernet adapter
      • 169.254.x.x
      • none

It is interesting to note that the 169.254.x.x address when applicable are always the same by default. If no address shows in the msh0 you can 

killall dhclient
dhclient           # Send DHCP request to force (if possible) to acquire a connection to a gateway

avahi-autoipd      # If no mesh gateway is available (MPP or School server) it will assign a zeroconf address(169.254.x.x)

DNS check

The most direct way to check Internet connectivity is by checking the resolv.conf file. It shows if the XO is registered to a DNS server. It can be viewed with, 

cat /etc/resolv.conf
  1. If it is empty,
    • No connection to the Internet (technically, no connection to the DNS server).
  2. If it includes a nameserver with private address (172.x.x.x, 169.168.x.x, 10.x.x.x),
    • Connected to an AP behind a NAT,
    • Connected to an MPP, which connects to an AP behind a NAT,
    • Connected to a School server (172.18.0.1 for the School server in OLPC offices, although others are also available).
  3. If it includes a nameserver with public address,
    • Connected to an AP without a NAT,
    • Connected to an MPP, which connects to an AP without a NAT.
  4. The is a rare possibility resulting from a NetworkManager failure, of an XO to have access to the Internet, but the resolv.conf to be blank. In that case, the XO will not be able to resolve hostnames. This possibility can be examined with,
ping www.mit.edu   # No replies
ping 18.7.22.83    # Normal replies

The general rule of thumb regarding the resolv.conf file in the lab XOs is the following:

  • empty: Link-local
  • 172.18.x.x: Schoolserver
  • 18.85.x.x: Media lab AP

If the XO connects to a channel that includes a School server or an MPP, but for some reason there is no Internet connectivity, and the resolv.conf file is empty, check if it is forced in Link-local or another configuration, 

nano /etc/NetworkManager/mesh-start # confirm that the file is empty(if it exists)

If the problem persists you can try, 

killall dhclient
dhclient           # Send DHCP request to force(if possible) to acquire a routable IP

Telepathy services

The Presence Service acquires information on other XOs in the network, and provides the capability to view them in the Neighborhood view, or share with them an activity. This is achieved through two child telepathy services, Salut and Gabble.

Salut

Salut runs when the XO is connected to a mesh. It uses the avahi _presence._tcp service. All XOs in the same mesh identify themselves in the Neighborhood view through Salut. They can be examined through, 

avahi-browse -t _presence._tcp

Jabber

Gabble will allow XOs that belong to different geographical locations to communicate with each other. It will detect Internet connectivity and connect to a Jabber server. All XOs connected to the same Jabber server will appear to the Neighborhood view. The currently possible servers are 

jabber.sugarlabs.org
jabber.laptop.org
olpc.collabora.co.uk
  • By build 616, the Presence Service does not allow Gabble and Salut to run simultaneously.
  • It constantly checks whether there is Internet connectivity, and switches from Salut to Gabble accordingly.
  • The XOs displayed in the Neighborhood view either belong to the mesh, or the Jabber server, not both.
  • The Internet connectivity does not work very accurately. It is very common when connected to the School server, which provides connectivity, that the XO is running Salut. However, it is convenient in the sense that it can now share activities with others in the mesh.

Detecting which service is running

  • The simpler way to detect whether Salut or Gabble is running is by observing the Neighborhood view. If you see XOs that you haven't seen in the lab, then you are probably running Gabble.
  • It can also be checked from the Analyze Activity - Interfaces tab - Presence Service - Buddies list - Handles column. The entries either start with ../gabble/jabber/.. or ../salut/local-xmpp/...
  • To confirm you are running Gabble you can check the config file for the [Server] (not Jabber) entry to be true. This, however, can be misleading, because the file doesn't update properly when you disconnect from the Jabber server. Thus, it usually includes obsolete information.
$ cat /home/olpc/.sugar/default/config
...
[Server]
registered = True             # running Gabble
server = jabber.laptop.org
  • The console provides a more efficient way of determining with confidence which service is running. The process list will include either a telepathy-salut or a telepathy-gabble process,
ps ax                         # general process list
ps U olpc -f|grep telepathy   # only the required entry will be displayed
  • The Jabber server to which the XO is connected (if it's running Gabble) can be examined using the netstat command,
netstat -tpT|grep telepathy   # the connection established by the telepathy-gabble process

Combine the tests in an automated script

All the above tests require checking many different locations and running several commands. Alternatively, you may run olpc-netstatus from the Terminal Activity or a console. It will accumulate and display the following network overview directly. This is a case of an XO connected to the School server on Channel 1. 

$olpc-netstatus

Model     : C2
Serial    : CSN74400049
MAC       : 00:17:C4:0C:CD:11

Build     : update.1 703
Firmware  : CL1 Q2D14 Q2D
Libertas  : 5.110.22.p1 

Nick      : W03
Uptime    : 01:12:06

IP eth0   : 172.18.0.250
IP msh0   : 169.254.5.77
DNS       : 172.18.0.1

Telepathy : gabble    
Jabber    : schoolserver.laptop.org
XOs       : 4

Essid     : olpc-mesh
Channel   : 1

School    : schoolserver.laptop.org
Config    : School Mesh

More up-to-date version of olpc-netstatus, and other useful Network tools are available at Network Resources.

Useful locations

You may need to be root to access some of these files

/etc/resolv.conf
DNS server
/etc/dhcpd.conf
check whether the XO acts as an MPP
/etc/NetworkManager/mesh-start
used to force a lower priority network configuration
/home/olpc/.sugar/default/config
user information
/home/olpc/.sugar/default/nm/networks.cfg
stores access points information, such as WEP password
/var/log/messages
main log file, may hold messages from NetworkManager
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