Changing the ttl threshold – Brocade TurboIron 24X Series Configuration Guide User Manual

Page 521

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Brocade TurboIron 24X Series Configuration Guide

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Configuring IP parameters – Layer 2 Switches

NOTE

In the above example, 10.157.22.199 is the IP address of the domain name server (default DNS
gateway address), and 10.157.22.80 represents the IP address of the NYC02 host.

FIGURE 60

Querying a Host on the newyork.com Domain

Changing the TTL threshold

The TTL threshold prevents routing loops by specifying the maximum number of router hops an IP
packet originated by the Layer 2 Switch can travel through. Each device capable of forwarding IP
that receives the packet decrements (decreases) the packet TTL by one. If a router receives a
packet with a TTL of 1 and reduces the TTL to zero, the router drops the packet.

The default TTL is 64. You can change the TTL to a value from 1 – 255.

To modify the TTL threshold to 25, enter the following commands.

TurboIron(config)#ip ttl 25

TurboIron(config)#exit

Type Control-c to abort

Sending DNS Query to 10.157.22.199

Tracing Route to IP node 10.157.22.80

To ABORT Trace Route, Please use stop-traceroute command.

Traced route to target IP node 10.157.22.80:

IP Address Round Trip Time1 Round Trip Time2

10.95.6.30 93 msec 121 msec

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