P-660H/HW-T Series User’ Guide
Chapter 10 Firewalls
124
All SMTP commands are illegal except for those displayed in the following tables.
10.4.2.3 Traceroute
Traceroute is a utility used to determine the path a packet takes between two endpoints.
Sometimes when a packet filter firewall is configured incorrectly an attacker can traceroute
the firewall gaining knowledge of the network topology inside the firewall.
Often, many DoS attacks also employ a technique known as "
IP Spoofing
" as part of their
attack. IP Spoofing may be used to break into systems, to hide the hacker's identity, or to
magnify the effect of the DoS attack. IP Spoofing is a technique used to gain unauthorized
access to computers by tricking a router or firewall into thinking that the communications are
coming from within the trusted network. To engage in IP spoofing, a hacker must modify the
packet headers so that it appears that the packets originate from a trusted host and should be
allowed through the router or firewall. The Prestige blocks all IP Spoofing attempts.
10.5 Stateful Inspection
With stateful inspection, fields of the packets are compared to packets that are already known
to be trusted. For example, if you access some outside service, the proxy server remembers
things about your original request, like the port number and source and destination addresses.
This “remembering” is called
saving the state.
When the outside system responds to your
request, the firewall compares the received packets with the saved state to determine if they
are allowed in. The Prestige uses stateful packet inspection to protect the private LAN from
hackers and vandals on the Internet. By default, the Prestige’s stateful inspection allows all
communications to the Internet that originate from the LAN, and blocks all traffic to the LAN
that originates from the Internet. In summary, stateful inspection:
• Allows all sessions originating from the LAN (local network) to the WAN (Internet).
• Denies all sessions originating from the WAN to the LAN.
RETARGET:
KEEPALIVE:
Table 36
Legal SMTP Commands
AUTH
DATA
EHLO
ETRN
EXPN
HELO
HELP
NOOP
QUIT
RCPT
RSET
SAML
SEND
SOML
TURN
VRFY
Table 35
Legal NetBIOS Commands
Summary of Contents for P-660H Series
Page 2: ......
Page 10: ...P 660H HW T Series User Guide 9 Customer Support ...
Page 32: ...P 660H HW T Series User Guide 31 List of Figures ...
Page 38: ...P 660H HW T Series User Guide 37 List of Tables ...
Page 42: ...P 660H HW T Series User Guide 41 Introduction to DSL ...
Page 62: ...P 660H HW T Series User Guide 61 Chapter 3 Wizard Setup for Internet Access ...
Page 90: ...P 660H HW T Series User Guide 89 Chapter 5 Wireless LAN ...
Page 132: ...P 660H HW T Series User Guide 131 Chapter 10 Firewalls ...
Page 162: ...P 660H HW T Series User Guide 161 Chapter 13 Remote Management Configuration ...
Page 176: ...P 660H HW T Series User Guide 175 Chapter 14 Universal Plug and Play UPnP ...
Page 182: ...P 660H HW T Series User Guide 181 Chapter 15 Logs Screens ...
Page 196: ...P 660H HW T Series User Guide 195 Chapter 16 Media Bandwidth Management Advanced Setup ...
Page 208: ...P 660H HW T Series User Guide 207 Chapter 17 Maintenance ...
Page 218: ...P 660H HW T Series User Guide 217 Chapter 19 Menu 1 General Setup ...
Page 222: ...P 660H HW T Series User Guide 221 Chapter 20 Menu 2 WAN Backup Setup ...
Page 226: ...P 660H HW T Series User Guide 225 Chapter 21 Menu 3 LAN Setup ...
Page 230: ...P 660H HW T Series User Guide 229 Chapter 22 Wireless LAN Setup ...
Page 236: ...P 660H HW T Series User Guide 235 Chapter 23 Internet Access ...
Page 250: ...P 660H HW T Series User Guide 249 Chapter 25 Static Route Setup ...
Page 254: ...P 660H HW T Series User Guide 253 Chapter 26 Bridging Setup ...
Page 270: ...P 660H HW T Series User Guide 269 Chapter 27 Network Address Translation NAT ...
Page 286: ...P 660H HW T Series User Guide 285 Chapter 29 Filter Configuration ...
Page 306: ...P 660H HW T Series User Guide 305 Chapter 32 System Information and Diagnosis ...
Page 318: ...P 660H HW T Series User Guide 317 Chapter 33 Firmware and Configuration File Maintenance ...
Page 324: ...P 660H HW T Series User Guide 323 Chapter 34 System Maintenance ...
Page 328: ...P 660H HW T Series User Guide 327 Chapter 35 Remote Management ...
Page 338: ...P 660H HW T Series User Guide 337 Chapter 36 IP Policy Routing ...
Page 342: ...P 660H HW T Series User Guide 341 Chapter 37 Call Scheduling ...
Page 358: ...P 660H HW T Series User Guide 357 Appendix A ...
Page 360: ...P 660H HW T Series User Guide 359 Appendix B ...
Page 384: ...P 660H HW T Series User Guide 383 Appendix D ...
Page 388: ...P 660H HW T Series User Guide 387 Appendix F ...
Page 394: ...P 660H HW T Series User Guide 393 Appendix G ...
Page 398: ...P 660H HW T Series User Guide 397 Appendix H ...
Page 401: ...P 660H HW T Series User Guide Appendix I 400 ...
Page 402: ...P 660H HW T Series User Guide 401 Appendix I ...
Page 456: ...P 660H HW T Series User Guide 455 Appendix M ...