To configure the host for CHARON networking do the following:

• List all the available network interfaces:

  # ifconfig

  
  

• Example - Displaying "eth" interfaces with "ifconfig" command

  # ifconfig | grep eth eth0 Link encap:Ethernet HWaddr 00:60:52:0A:A9:1E eth1 Link encap:Ethernet HWaddr 00:C0:26:60:FB:15 eth2 Link encap:Ethernet HWaddr 00:1A:92:E1:3F:7F

  
  

• Choose some interface to be used by CHARON, for example "eth1"
• Open up the file "/etc/sysconfig/network-scripts/ifcfg-ethN" (where N is number of the interface to be used for CHARON, in our case is "1") and make sure that all the IP-setup related parameters are removed.

  • Basically the file must look like the following example:

    DEVICE="eth1" HWADDR="00:06:2B:00:6A:87" NM_CONTROLLED="no" ONBOOT="no"

    
    

• Switch off the offload parameters for chosen network interface using "ethtool" utility.

  • A first step is to find what additional paramaters are currently set to "on" on the host network adapter to be used by CHARON. To do that issue:

    # ethtool -k <device>

    ethtool will return the offload parameters and their values
    
    

  • Example:

    # ethtool -k eth1 Offload parameters for eth1: rx-checksumming: on tx-checksumming: on scatter-gather: on tcp-segmentation-offload: off udp-fragmentation-offload: off generic-segmentation-offload: on generic-receive-offload: off large-receive-offload: off

    
    

  • Then use ethtool to switch off all the offload parameters:

    # ethtool -K <device> <parameter> off

    
    

  • Example:

    # ethtool -K eth1 rx off # ethtool -K eth1 tx off # ethtool -K eth1 sg off # ethtool -K eth1 gso off

    
    

  • For the example above let's create a temporary file containing the commands to be run on system startup, since the offload parameters must be switched off on each reboot
    • Let's suppose that the name of the file is "offload_off_eth1.txt". In this case running it on system startup can be done in the following ways:

      • On Red Hat Linux:

        # cat offload_off_eth1.txt >> /etc/rc.d/rc.local

        
        

      • On Fedora Core:

        # echo '#!/usr/bin/bash' > /etc/rc.d/rc.local # cat offload_off_eth1.txt >> /etc/rc.d/rc.local # chmod 755 /etc/rc.d/rc.local # ln -s /usr/lib/systemd/system/rc-local.service /etc/systemd/system/rc-local.service # systemctl daemon-reload

        
        

• • Reboot the host system to apply the offload parameters switching off