Firewall configuration
Digi TransPort User Guide
657
Firewall script rule fields
Firewall script rule fields are as follows:
[action]
Can be specified as
block
,
pass
,
pass-ifup
,
dscp
,
vdscp
, or
debug
. These operate as follows:
block
Prevents a packet from being allowed through the firewall. When block is specified, an
optional field can be included that causes an ICMP packet to be returned to the interface from
which that packet was received. This technique is sometimes used to confuse hackers by
having different responses to different packets or for fooling an attacker into thinking a service
is not present on a network.
The syntax for specifying the return of an ICMP packet is:
“return-icmp” [icmp-type [icmp-code]]
where
[icmp_type]
is a decimal number representing the ICMP type, or one of the predefined
text codes listed in the following table:
ICMP type value ICMP type
1
Unreach
2
Echo
3
Echorep
4
squench
5
redir
6
timex
7
paraprob
8
timest
9
timestrap
10
inforeq
11
inforep
12
maskreg
13
maskrep
14
routerad
15
routersol