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Chapter 13. Network Diagnostic Tools
Various network diagnostic tools are provided by the FB6000, accessible through either the web user interface
or the CLI :-
• Packet dump : low level diagnostics to for detailed examination of network traffic passing through the
FB6000
• Ping : standard ICMP echo request/reply ping mechanism
• Traceroute : classical traceroute procedure - ICMP echo request packets with increasing TTL values,
soliciting "TTL expired" responses from routers along the path
• Access check : check whether a specific IP address is allowed to access the various network services
described in Chapter 12
• Firewall check : check how the FB6000 would treat specific traffic when deciding whether to establish a
new session (as per the processing flow described in Section 7.3.2)
Each tool produces a textual result, and can be accessed via the CLI, where the same result text will be shown.
Caution
The diagnostic tools provided are not a substitute for external penetration testing - they are intended
to aid understanding of FB6000 configuration, assist in development of your configuration, and for
diagnosing problems with the behaviour of the FB6000 itself.
13.1. Firewalling check
The FB6000 follows a defined processing flow when it comes to deciding whether to establish a new session
- see Section 7.2 for an overview of session tracking, and its role in implementing firewalling. The processing
flow used to decide whether to allow a session i.e. to implement firewalling requirements, is covered in
Section 7.3.2.
The firewalling check diagnostic facility allows you to submit the following traffic parameters, and the FB6000
will show how the processing flow procedes given those parameters - at the end of this is a statement of whether
the session will be allowed or not :-
• Source IP address
• Target IP address
• Protocol number (1=ICMP, 6=TCP, 17=UDP, 58=ICMPv6)
• Target port number (only for protocols using port numbers, e.g. TCP/UDP)
• Source port number - OPTIONAL
In the web user interface, this facility is accessed by clicking on "Firewall check" in the "Diagnostics" menu.
Once you have filled in the required parameters, and clicked the "Check" button, the FB6000 will produce a
textual report of how the processing flow proceded (it may be helpful to also refer to the flow chart shown
in Figure 7.2).
For example, if we submit parameters that describe inbound (i.e. from a WAN connection) traffic that would
result from trying to access a service on a host behind the FB6000, we have implemented a 'default drop' policy
firewalling method, and we have not explicitly allowed such sessions, we would see :-
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