Google Networking Best Practices for Large Deployments User Manual
Page 15
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Network Evaluation
15
1. Open the sample list
. (Note that
this is a sample only, not a complete list.)
2. Save the sample .txt file in the directory where you will be using the test commands:
a. Click View raw file.
b. Right-click the page, and choose Save As.
3. Run the following command to test DNS resolution:
% dig +all +trace -f GoogleAppsDomains.txt
ICMP Connectivity Test
Ensure that clients in your network can reach the hostname
mail.google.com
, by testing
ICMP connectivity from all your network locations to Google Apps. Test that your users can
reach Google Apps, especially from all users’ VLANs.
% ping -s 512 -c 400 -n mail.google.com
If you see slow or failed connections on your ping requests, this may indicate a loss of
connectivity. Investigate each step of your connection to identify the source of the problem.
TCP/UDP Reliability Test
Ensure that clients in your network can reliably establish and maintain a connection to Google
Apps servers. Use the
Hping
tool to test link reliability over a period of time. Run the following
command:
% time hping3 -S mail.google.com -p 443 --fast -c 1000
If there is time, run this test for each domain listed in the
GoogleAppsDomains.txt
file
mentioned above.
Note:
TCP/UDP reliability tests are intrusive and can affect network performance. Run these
tests during off-hours to gather data while causing the minimum possible the impact to
your network.
Available WAN Bandwidth Assessment
Use the
iperf
tool to assess the amount of bandwidth available from each location to its
network egress point. This test is run on both the client and the network egress point.
This test is intended to assess bandwidth within your WAN network. It is not suited for testing
bandwidth between your network and Google Apps servers.
On each remote location that is connected over a WAN network, run this command:
% iperf -c CLIENT IP ADDRESS -d
On the network egress location, run this command: