Filter
How do I know what packet is triggering the call?
If the user already knows the protocol type, the source port and the IP address of the packet that is triggering the call, he can design the filter rule based on these information. Otherwise, he can take a look at the SMT Menu 24.1 to see what is the exact packet that triggers the outgoing call. The 'LAN Packet Which Triggered Last Call' status in Menu 24.1 will show you the packet which triggers the call. A display of the header of the packets is shown next.
LAN Packet which Triggered Last Call: (Type: IP)
45 00 00 2E CA 0E 40 00 1F 06 D7 09 CC F7 CB B4 CC D9 00 02 04 1C 00 15 00 33 2D 5E 55 80 B5 C0 50 18 1F 9B E7 D4 00 00 50 41 53 56 0D 0A |
We list the header of the IP, UDP and TCP in order to make you know more about the format of the IP packet and IPX packet in Menu 24.1 for easy configuration of a filter rule.
IP Header
0 15 16 31
4-bit |
4-bit |
8-bit type of service |
16-bit total length (in bytes) |
||
16-bit identification |
3-bit |
13-bit fragment offset |
|||
8-bit time to live(TTL) |
8-bit protocol |
16-bit header checksum |
|||
32-bit source IP address |
|||||
32-bit destination IP address |
|||||
Option (if any) |
|||||
Data |
UDP Header
0 15 16 31
16-bit source port number | 16-bit destination port number |
16-bit UDP length | 16-bit UDP checksum |
Data (if any) |
TCP Header
0 15 16 31
16-bit source port number |
16-bit destination port number |
|||||||
32-bit sequence number |
||||||||
32-bit acknowledgment number |
||||||||
4-bit header length | Reserved |
U |
A |
P |
R |
S |
F |
16-bit window size |
16-bit TCP checksum |
16-bit urgent pointer |
|||||||
Option (if any) |
||||||||
Data (if any) |
Based on the above headers, we can then interpret the LAN Packet Which Triggered Last Call as following:
LAN Packet which Triggered Last Call : (Type: IP) 45 00 00 2E CA 0E 40 00 1F 06 D7 09 CC F7 CB B4 CC D9 00 02 04 1C 00 15 |
06 = TCP Protocol
CC F7 CB B4= 204.247.203.180 = Source IP
CC D9 00 02= 204.217.0.2 = Destination IP
04 1C=1052(dec)= Source port number
00 15= 21(dec)=Destination port number = FTP
port
IPX header in Menu 24.1:
LAN Packet Which Triggered Last Call: (Type: IPX) 00 28 01 01 00 00 00 00 FF FF FF FF FF FF 04 53 00 00 00 00 00 00 00 00 00 0004 53 00 01 FF FF FF FF FF 00 00 00 00 |
01
IPX packet type
00 00 00
00 Destination network
number
FF FF FF FF FF FF Destination node number
04
53
Destination socket number
00 00 00 00 Source network number
00 00 00 00 00 00 Source node
number
04 53
Source socket number
IPX packet type:
01=RIP
02=echo
03=error
04=SAP
05=SPX
11=NCP
14=NetBIOS
Socket number:
0451=NCP
0451=SAP
0453=RIP
0455=NetBIOS
All contents copyright © 1999 ZyXEL Communications Corporation.