[c-nsp] MTU Testing

[Paul Magee]

Hi,

The simplest way would be to ping your host from the dhcp server with packet size of just above and just below your desired mtu size with the df-bit set

Eg.
To test for an MTU of 1500

# ping -s 1472 192.168.1.50 -M do
PING 192.168.1.50 (192.168.1.50) 1472(1500) bytes of data.
1480 bytes from 192.168.1.50: icmp_req=1 ttl=64 time=0.362 ms
1480 bytes from 192.168.1.50: icmp_req=2 ttl=64 time=0.293 ms

# ping -s 1473 192.168.1.50 -M do
PING 192.168.1.50 (192.168.1.50) 1473(1501) bytes of data.
>From 192.168.1.1 icmp_seq=1 Frag needed and DF set (mtu = 1500)
>From 192.168.1.1 icmp_seq=1 Frag needed and DF set (mtu = 1500)

HTH

Paul




-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of M K
Sent: 13 November 2012 12:17
To: cisco-nsp at puck.nether.net
Subject: [c-nsp] MTU Testing


Hi , am trying to configure my linux DHCP server to send the MTU size (Option 26) in the DHCP server Now , what are the best ways to test if the value sent via the offer is correct and as configured?
Thanks 		 	   		  
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