Security
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• ‘TFTP’: The Eicon 1550/1551 can function as a TFTP server to support uploading
and downloading of configuration files. If you filter TFTP traffic, you will not be able
to use this feature.
• ‘DNS’: Domain name system. Filtering DNS datagrams can cause disruptions in the
ability to access remote sites.
The following options are also available: NFS/RPC, News, Time (NTP), BOOTP,
SNMP, ICMP, Ping (ICMP), Ping Reply, ICMP Redir. For a description of these
protocols, consult the appropriate RFC at the site http://www.faqs.org/.
Warning: Be Careful when Creating Filters
Filters are a very powerful tool. Be careful when creating filters, since you may
accidentally define a filter that could bar all incoming and outgoing data, including
access to the Eicon 1550/1551’s web or command line interface to change settings.
Please read
Default Filters
on page 68 before experimenting with filters.
If you find you have accidentally filtered yourself out of access to the Eicon 1550/1551,
you must reset the box to factory defaults by holding down the reset button for 15
seconds. However, you will lose all configuration information. As a precaution, back up
your configuration before using filters.
Default Filters
When a profile has no filters defined, a default filter is automatically supplied by the
Eicon 1550/1551, as shown below.
The default filter forwards all packets from anywhere, and allows all traffic through
unimpeded. The default filter is always the last filter in the stack and cannot be edited.
Default
filter
