Difference between revisions of "MTU/MSS - How to test using PING"

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(Created page with "Category:Wireshark MTU = max transmission unit of a Layer 2 Frame<br /> MSS = max segment size of a Layer 4 protocol<br /> <br /> For TCP/IP:<br /> MSS = MTU-40 (TCP and IP h...")
 
 
(2 intermediate revisions by 2 users not shown)
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[[Category:Wireshark]]
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[[Category:Wireshark and Network Testing]]
 
MTU = max transmission unit of a Layer 2 Frame<br />
 
MTU = max transmission unit of a Layer 2 Frame<br />
 
MSS = max segment size of a Layer 4 protocol<br />
 
MSS = max segment size of a Layer 4 protocol<br />
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For TCP/IP:<br />
 
For TCP/IP:<br />
 
MSS = MTU-40 (TCP and IP headers are 40 bytes)<br />
 
MSS = MTU-40 (TCP and IP headers are 40 bytes)<br />
ping -f -l X (set do not fragment and set icmp payload to X)<br />
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<br />
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Testing MTU using Winodws ping command<br />
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ping -f -l X hostname  (set do not fragment and set icmp payload to X)
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Simple loop for Windows ping testing
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FOR /L %A IN (1200,1,1473) DO ping -f -n 3 -l %A hostname >> C:\mtu-test.txt
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If X = 1388 gets a reponse then<br />
 
If X = 1388 gets a reponse then<br />
MTU = X + 28 (for ICMP and IP header)<br />
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MTU = X + 28 (20 for IP header and 8 for the ICMP header)<br />
 
MTU = 1416<br />
 
MTU = 1416<br />
 
 
MSS = 1416 - 40 = 1376
 
MSS = 1416 - 40 = 1376

Latest revision as of 03:23, 10 June 2013

MTU = max transmission unit of a Layer 2 Frame
MSS = max segment size of a Layer 4 protocol

For TCP/IP:
MSS = MTU-40 (TCP and IP headers are 40 bytes)

Testing MTU using Winodws ping command

ping -f -l X hostname   (set do not fragment and set icmp payload to X)

Simple loop for Windows ping testing

FOR /L %A IN (1200,1,1473) DO ping -f -n 3 -l %A hostname >> C:\mtu-test.txt

If X = 1388 gets a reponse then
MTU = X + 28 (20 for IP header and 8 for the ICMP header)
MTU = 1416
MSS = 1416 - 40 = 1376