Mar 102014

I’ve been trying to use Cacti to graph my ADSL’s Sync rate and SNR/Attenuation Ratios for the past few weeks as I’ve been having issues with my ADSL.

Originally, I was using a BigPond Thomson ST536v6, but unfortunately, the SNMP agent on the Thomson will only expose the Sync Rate, and not the SNR and Attenuation.

So I have decided to use an old SpeedStream 4200 instead. The default SNMP community string is ‘public’ but I wanted to change it to my private one.

To change the SNMP community string, you need to telnet onto the modem to change it.

Once you’ve telnetted in, you can show the current snmp settings with this command –
xsh> cfg snmp
The output will show you the current configuration.
nam = ""
rd = n
wr = n
dsbl = n

These settings just mean that the default settings are applied.
To update the snmp community string, you need to use the following command –

cfg snmp{comm#0{nam=skynet
cfg snmp{comm#0{rd=y

Those 2 lines will set the community string to “skynet” and set the permissions to readonly.

After setting these, run the command cfg save to save the configuration, and then reboot the modem. This will allow the new settings to take affect.