Advanced Networking

Overview

There are many thing that GWS(The Configuration Software for Telem-GW6) can't do. For instance NTP, VLAN and OpenVPN configuration. If something extra is needed then in general user's should create Linux scripts and copy them to Telem-GW6. Sometimes a change of an existing script is enough. Example scripts can be found from Telem-GW6 /usr/local/bin/ folder.

Location of Startup Scripts

/etc/init.d/

Scripts in this folder are run at system startup.

/etc/network/if-ud.d/ and /etc/network/if-down.d/

Scripts in this folder are run when an interface(for instance ethernet interface eth0) becomes available or unavailable. These scripts are needed(used) for instance for configuring the firewall or routing.

/etc/ppp/ip-up or /etc/ppp/ip-down

Scripts in this folder are run when an PPP interface becomes available or unavailable. These scripts are needed(used) for instance for configuring the firewall or routing.

Examples

A good example that is in use in production systems is NTP or PPP. Both are located at /usr/local/bin.

VLAN

For instane a script like this makes a single VLAN called vlan30

# Script to show creation of VLAN's
# Copy it to /etc/network/if-up.d and change file permissions to make it executable.
if [ "$IFACE" == "eth0" ]
then
    logger "vlan_enable for interface:$IFACE"

    # So that from ifconfig we see vlan30 not eth0:30
    vconfig set_name_type VLAN_PLUS_VID_NO_PAD

    vconfig rem vlan30
    vconfig add eth0 30
    vconfig set_egress_map vlan30 0 7
    vconfig set_ingress_map vlan30 0 7
    ifconfig vlan30 172.22.101.196 netmask 255.255.255.240 txqueuelen 1000 up
    route add default gw 172.22.101.193 vlan30
fi

Troubleshooting

For troubleshooting use tcpdump [1]: A powerful command-line packet analyzer or netstat [2]: Is a command-line tool that displays network connections.