I need to change the default TTL of TCP/IP packets sent from my Ubuntu computer. I found the solution for Windows:

  1. To make reg-file:

    Windows Registry Editor Version 5.00
    
    [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\servic es\Tcpip\Parameters]
    "DefaultTTL"=dword:00000081
    
  2. To execute this commands in console:

    netsh int ipv4 set glob defaultcurhoplimit=129
    netsh int ipv6 set glob defaultcurhoplimit=129
    

The question is how should I translate this solution for Ubuntu?

up vote 14 down vote accepted

To change the default TTL of TCP/IP packets sent from your Linux computer you can run the following command:

sudo sysctl net.ipv4.ip_default_ttl=129

Or:

echo 129 | sudo tee /proc/sys/net/ipv4/ip_default_ttl

Or:

sudo bash -c 'echo 129 > /proc/sys/net/ipv4/ip_default_ttl'

But you have to run one of those commands whenever the computer boots. To make this setting persistent across reboots you could append the following line to the file /etc/sysctl.conf:

net.ipv4.ip_default_ttl=129
  • I used nano to edit /proc/sys/net/ipv4/ip_default_ttl and now I can't see any of my wifi networks – Arya Jul 3 at 3:47

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