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ServPoET FAQs

Question

What is the maximum upper limit of ip_conntrack?

Answer

16k connections per 1Gb of RAM

See sysctl net.netfilter.nf_conntrack_max

Question

What are the commands to search for a subscriber within the ServPoET NOS?

Answer

On the command line:

ps x | grep ‘username’

In the rpconfig GUI:

rpconfig®server status®search for ‘username’

Question

Does ServPoET have a built-in SNMP agent?  If so, what MIBs are supported?

Answer

The MIB is just the standard Linux kernel MIB, SNMP is limited to read-only in the current version, but is under active development to support full read/write.

Question

If VLANs on the PPP interface are created, are any of the PPP Options affected?

Answer

When VLANs on the PPP Interface are created, the MTU setting in “Configure PPP Options” both Maximum transfer, and Maximum receive unit need to be no more than 1488, 4 bytes of header created by the VLAN and 8 bytes created for the PPPoE header.

Question

How does ServPoET handle multiple RADIUS servers?

Answer

Use the ServPoET configuration GUI (rpconfig) to define multiple RADIUS servers (Realms → Configure RADIUS → Add).  If multiple RADIUS servers are specified, they are tried in round-robin fashion if one server is not answering.

Question

How to log ServPoET activity to remote SYSLOG server?

Answer

NOTE: logging will reduce system performance.

Logging to a remote system, requires that this system runs a SYSLOG daemon.  This is easiest done with a remote Linux server, as all such installs run SYSLOG already.  Note that your Linux server may need to be configured to accept remote SYSLOG connections.  The steps to enable this are Linux distribution/version dependent.

Once the remote SYSLOG server is configured to accept remote logs, you can select the ‘Configure Logging’ in the ServPoET GUI to enable logging to this server.

Question

How to log ServPoET activity to a local file?

Answer

NOTE: logging will reduce system performance.

  • vi /etc/syslog.conf
  • add a single line:
    1. *.* /var/log/message
  • Save/quit file – command line: wq
  • And restart syslog
    1. /etc/init.d/syslog restart
  • And start listening and logging to stdout
    1. tail -f /var/log/message

Question

How do you capture real time PPPoE activity on ServPoET?

Answer

NOTE: capturing traffic will reduce system performance.

ServPoET command line can be used to capture Ethernet traffic using the ‘tcpdump’ tool.  This tool will capture all packets from a given interface and display them or store them in a file.  Refer to tcpdump documentation for further details.

Here are some useful invocations…

  • show PPPoE discovery packets
    1. # tcpdump -i eth3 pppoed
  • show PPPoE sessions packets, and filter encapsulated content
    1. # tcpdump -i eth3 pppoes and icmp and host 10.10.10.10
  • show more detail from PPPoE discovery packets
    1. # tcpdump -vvv -i eth3 pppoed
  • capture PPPoE discovery and session packets into a file for analysis
    1. # tcpdump -i eth3 -w /tmp/pppoe-capture-file pppoed or pppoes

Question

How do you export configuration files from ServPoET?

Answer

ServPoET GUI (rpconfig) Backup functionality will generate a file in ‘/etc/sysconfig/rpconfigBK.dat’ which can be copied to another system.  This file holds all configuration options assigned through the GUI.  After backup, it’s advised to copy this file to safe location.

To restore from this file, copy the backup back into the same location.  Select Restore from the Backup/Restore GUI menu.

Question

How do you bypass RADIUS authentication?

Answer

In order to bypass RADIUS authentication and to terminate the session locally,

follow these steps in the ServPoET GUI (rpconfig):

  • Select the REALM to edit (Ctrl-R)
  • Select ‘Realms’ menu option
  • Select ‘Configure PPP Options’ menu option
  • Navigate to ‘Additional pppd options…’
  • Type in ‘noauth’ on its own line
  • Select OK to accept edit
  • Select OK to accept changes

Question

How to preserve changes made to file in /etc.

Answer

The ServPoET NOS accesses the flash media in a read-only manner, except for to update configuration files.  The GUI will automatically update the flash media, when a configuration change was made.  Should any additional changes be made to the /etc file (like updating ssh keys, or adding custom scripts), these changes will not be automatically preserved and maintained to the next boot.  In order to store them to flash run: ‘preserve-etc’.

Problem

Neighbor overflow issue – ‘operation not permitted’

Resolution

  • Add the following line in /etc/sysctl.conf:
  • ipv4.neigh.default.gc_thresh3 = 4096
  • And then, run ‘sysctl -p’ to activat

Make the changes in sysctl.conf permanently run: ‘preserve-etc’ at the command line.