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Figure 6.3. Fixed DHCP Lease Confi guration Page
6.1.5.2  Add a Fixed DHCP Lease
To add a fi xed DHCP lease, follow the instructions below:
1.  Open  the  Fixed  DHCP  Lease  confi guration  page,  as  shown  in  Figure 6.3, by clicking Advanced ->DHCP Server menu.
2.  Enter  the  MAC  address  and  the  desired  IP  address  of  the  host  requiring a fi xed IP address. Table 6.2 describes the fi xed DHCP 
lease confi guration parameters in detail.
Table 6.2. Fixed DHCP Lease Confi guration Parameters
FieldDescription
Fixed DHCP Lease 
MAC A hardware ID of the device that needs a fi xed 
IP address from the DHCP server.
Fixed DHCP Lease 
IP The IP address leased from the DHCP server. 
Note that it is recommended that this IP 
address be outside of the DHCP IP pool.
3. Click on the  Add button to add the new fi xed DHCP lease entry.
6.1.5.3  Delete a Fixed DHCP Lease
To  delete  a  fixed  DHCP  lease,  click  on  the     in  front  of  the 
specifi c fi xed DHCP lease to be deleted.
6.1.5.4  Viewing Fixed DHCP Lease Table
To  see  existing  inbound  fixed  DHCP  lease,  just  open  the  Fixed   
						

							
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DHCP  Lease  configuration  page  by  clicking  Advanced  ->DHCP 
Server menu
6.2  DNS
6.2.1  About DNS 
Domain Name System (DNS) servers map the user-friendly domain 
names  that  users  type  into  their  Web  browsers  (e.g.,  “yahoo.com”) 
to  the  equivalent  numerical  IP  addresses  that  are  used  for  Internet 
routing.
When a PC user types a domain name into a browser, the PC must 
first  send  a  request  to  a  DNS  server  to  obtain  the  equivalent  IP 
address.  The  DNS  server  will  attempt  to  look  up  the  domain  name 
in  its  own  database,  and  will  communicate  with  higher-level  DNS 
servers when the name cannot be found locally. When the address 
is found, it is sent back to the requesting PC and is referenced in IP 
packets for the remainder of the communication.
6.2.2  Assigning DNS Addresses
Multiple  DNS  addresses  are  useful  to  provide  alternatives  when 
one  of  the  servers  is  down  or  is  encountering  heavy  traffic.  ISPs 
typically  provide  primary  and  secondary  DNS  addresses,  and  may 
provide  additional  addresses.  Your  LAN  PCs  learn  these  DNS 
addresses in one of the following ways:•    Statically:  If  your  ISP  provides  you  with  their  DNS  server  addresses,  you  can  assign  them  to  each  PC  by  modifying  the 
PCsʼ IP properties.
•    Dynamically  from  a  DHCP  Server:  You  can  configure  the  DNS  addresses  in  the  DHCP  server  in  the  RX3042H  and  allow  the 
DHCP server to distribute the DNS addresses to the PCs. Refer 
to  the  section  6.1.3  “Configuring  DHCP  Server”  for  instructions 
on configuring DHCP server.
In  either  case,  you  can  specify  the  actual  addresses  of  the  ISPʼs 
DNS servers (on the PC or in the DHCP Server configuration page), 
or  you  can  specify  the  address  of  the  LAN  port  on  the  RX3042H 
(e.g., 192.168.1.1). When you specify the LAN port IP address, the 
device performs DNS relay, as described in the following section. 
						

							
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Note:  If  you  specify  the  actual  DNS  addresses  on  the 
PCs or in the DHCP pool, the DNS relay feature is not  used.
6.2.3  Configuring DNS Relay
When  you  specify  the  deviceʼs  LAN  port  IP  address  as  the  DNS 
address,  then  the  Internet  Security  Router  automatically  performs 
“DNS  relay”;  i.e.,  because  the  device  itself  is  not  a  DNS  server,  it 
forwards  domain  name  lookup  requests  from  the  LAN  PCs  to  a 
DNS server at the ISP. It then relays the DNS serverʼs response to 
the PC. 
When  performing  DNS  relay,  the  RX3042H  must  maintain  the 
IP  addresses  of  the  DNS  servers  it  contacts.  It  can  learn  these 
addresses in either or both of the following ways:
•    Learned  through  PPPoE  or  Dynamic  IP  Connection:  If  the  RX3042H  uses  a  PPPoE  (see  section  5.2.2  PPPoE  or  5.2.3 
P P P o E   U n n u m b e r e d )   o r   D y n a m i c   I P   ( s e e   s e c t i o n   5 . 2 . 4 
Dynamic  IP)  connection  to  the  ISP,  the  primary  and  secondary 
DNS  addresses  can  be  learned  via  the  PPPoE  protocol.  Using 
this  option  provides  the  advantage  that  you  will  not  need  to 
reconfigure  the  PCs  or  the  RX3042H  if  the  ISP  changes  their 
DNS addresses.
•    Configured  on  the  RX3042H:  You  can  also  specify  the  ISPʼs  DNS  addresses  in  the  WAN  configuration  page  as  shown  in 
Figure 5.3, Figure 5.4 or Figure 5.5 or Figure 5.6.
Follow these steps to configure DNS relay: 1 .  Enter  LAN  IP  in  the  DNS  Server  IP  Address  field  in  DHCP  configuration page as shown in Figure 6.1.
2.  Configure  the  LAN  PCs  to  use  the  IP  addresses  assigned  by  the  DHCP  server  on  the  Internet  Security  Router,  or  enter  the 
Internet  Security  Routerʼs  LAN  IP  address  as  their  DNS  server 
address manually for each PC on your LAN.
Note:  DNS  addresses  that  are  assigned  to  LAN  PCs prior  to  enabling  DNS  relay  will  remain  in  effect  until  the  PC  is  rebooted.  DNS  relay  will  only  take  effect 
when a PCʼs DNS address is the LAN IP address.
Similarly, if after enabling DNS relay, you specify a  
						

							
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DNS  address  (other  than  the  LAN  IP  address)  in  a DHCP  pool  or  statically  on  a  PC,  then  that  address 
will be used instead of the DNS relay address. 
						

							
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7  Routing
You  can  use  Configuration  Manager  to  define  specific  routes 
for  your  Internet  and  network  data  communication.  This  chapter 
describes  basic  routing  concepts  and  provides  instructions  for 
creating  static  routes.  Note  that  most  users  do  not  need  to  define 
static routes.
7.1  Overview of IP Routes
The  essential  challenge  of  a  router  is:  when  it  receives  data 
intended  for  a  particular  destination,  which  next  device  should  it 
send that data to? When you define IP routes, you provide the rules 
that the RX3042H uses to make these decisions. 
7.1.1  Do I need to define static routes?
Most  users  do  not  need  to  define  static  routes.  On  a  typical  small 
home  or  office  network,  the  existing  routes  that  set  up  the  default 
gateways for your LAN computers and for the RX3042H provide the 
most appropriate path for all your Internet traffic.
•    On  your  LAN  computers,  a  default  gateway  directs  all  Internet  traffic  to  the  LAN  port  on  the  RX3042H.  Your  LAN  computers 
know  their  default  gateway  either  because  you  assigned  it  to 
them  when  you  modified  their  TCP/IP  properties,  or  because 
you configured them to receive the information dynamically from 
a  server  whenever  they  access  the  Internet.  (Each  of  these 
processes  is  described  in  the  Quick  Start  Guide  instructions, 
Part 2.)
•    On  the  RX3042H  itself,  a  default  gateway  is  defined  to  direct  all  outbound  Internet  traffic  to  a  router  at  your  ISP.  This  default 
gateway  is  assigned  automatically  by  your  ISP  whenever  the 
device  negotiates  an  Internet  connection.  (The  process  for 
adding a default route is described in section 7.3.2 Adding Static 
Routes.)
You  may  need  to  define  static  routes  if  your  home  setup  includes 
two or more networks or subnets, if you connect to two or more ISP 
services, or if you connect to a remote corporate LAN. 
						

							
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7.2 Dynamic Routing using RIP (Routing   
  Information Protocol)
RIP  enables  routing  information  exchange  between  routers;  thus, 
routes  are  updated  automatically  without  human  intervention. 
It  is  recommended  that  you  enable  RIP  in  the  System  Services 
Configuration Page as shown in Figure 10.1.
Figure 7.1.  RIP Configuration Page
7.2.1  RIP Configuration Parameters
The  following  table  defines  the  available  configuration  parameters 
for static routing configuration.
Table 7.1. Static Route Configuration Parameters
FieldDescription
Interface Select an interface through which the routing 
information is exchanged. Available options are 
LAN, WAN1, WAN2, PPPoE1, PPPoE2, PPPoE3 
and PPPoE4.
RIPClick the “Enable” or “Disable” radio button to 
enable or disable “RIP” for the interface selected. 
Note that you must enable RIP service first in the 
Management / System Services configuration 
page first. 
						

							
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FieldDescription
Passive ModeEnable this mode if RIP configured for this interface 
will only receive routing information from other 
routers and not send routing information to other 
routers. Disable this mode if you want this interface 
to send and receive routing information to/from 
other routers.
RIP Version 
(Send) Select the RIP version for sending the routing 
information. Three options are available: Version 1. 
Version 2 and Both.
RIP Version 
(Receive) Select the RIP version for receiving the routing 
information. Three options are available: Version 1. 
Version 2 and Both.
AuthenticationClick on “Enable” or “Disable” radio button to 
enable/disable authentication for exchanging 
the routing information. Note that all the routers 
exchanging routing information must use the 
same authentication key.
Authentication 
Mode
Select RIP authentication mode from the drop 
down list. Two modes are supported - Clear Text 
and MD5.
Authentication 
KeyEnter the authentication key shared by all the 
routers exchanging the routing information.
7.2.2  Configuring RIP
Follow these instructions to enable or disable RIP:
1 .   I n   t h e   S y s t e m   S e r v i c e s   C o n f i g u r a t i o n   p a g e   ( a s   s h o w n 
in  Figure  10.1),  click  the  Enable  or 
Disable   radio  button 
depending on whether you want to enable or disable RIP.
2. Select an interface from the drop-down list for routing information  exchange.
3.  Click  the  Enable  radio  button  to  enable  RIP  for  the  particular 
interface selected.
4.  Decide  whether  the  RIP  is  operated  in  passive  mode  or  not  by 
clicking the Enable or Disable radio button.
5.  Choose  RIP  version  for  sending  and  receiving  the  routing  
						

							
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information. Available options are Version 1, Version 2 and Both.
6.  Choose  whether  authentication  is  required  by  clicking  the 
Enable or Disable radio button.
7.  (Optional)  If  authentication  is  enable,  you  must  also  select  authentication mode and the desired authentication key.
8.  Click Apply to save the settings.
7.3  Static Route
Figure 7.2.  Static Route Configuration Page
7.3.1  Static Route Configuration Parameters
The  following  table  defines  the  available  configuration  parameters 
for static routing configuration.
Table 7.2. Static Route Configuration Parameters
FieldDescription
Destination 
Address
Specifies  the  IP  address  of  the  destination  computer  or 
an  entire  destination  network.  It  can  also  be  specified 
as  all  zeros  to  indicate  that  this  route  should  be  used  for 
all  destinations  for  which  no  other  route  is  defined  (this 
is  the  route  that  creates  the  default  gateway).  Note  that 
destination IP must be a network ID. The default route uses 
a  destination  IP  of  0.0.0.0.  Refer  to Appendix  11  for  an 
explanation of network ID. 
						

							
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FieldDescription
Subnet 
Mask
Indicates which parts of the destination address refer to the 
network and which parts refer to a computer on the network. 
Refer to Appendix 11, for an explanation of network masks. 
The default route uses a 0.0.0.0 for subnet mask.
GatewayGateway IP address
InterfaceAvailable  option  include AUTO,  Eth0  (LAN),  Eth1  (WAN), 
PPPoE:0  (unnumbered),  PPPoE:1  (1st  PPPoE  session), 
PPPoE:2  (2nd  PPPoE  session).  These  options  are 
selectable from the drop-down list. If AUTO is selected, the 
router  will  automatically  assign  an  interface  to  route  the 
packets based on the gateway IP address.
7.3.2  Adding Static Routes
Figure 7.3.  Static Route Configuration
Follow these instructions to add a static route to the routing table.
1. Open the Static Route configuration page by clicking the 
Advanced ->Static Route menu.
2. Enter static routes information such as destination IP address,  destination subnet mask, gateway IP address and the interface 
in the corresponding fields.
For  a  description  of  these  fields,  refer  to  Table  7.2.  Static 
Route Configuration Parameters.
To  create  a  route  that  defines  the  default  gateway  for  your 
LAN,  enter  0.0.0.0  in  both  the  Destination  IP  Address  and 
Subnet Mask fields.
3. Click Add to add a new route. 
						

							
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7.3.3  Deleting Static Routes
Figure 7.4.  Sample Routing Table
Follow  these  instructions  to  delete  a  static  route  from  the  routing 
table.1.  Open  the  Static  Route  configuration  page  by  clicking  the 
Advanced ->Static Route menu.
2.  Click  on  the 
  icon  of  the  route  to  be  deleted  in  the  Routing 
Table.
WARNING  D o   n o t   r e m o v e   t h e   r o u t e   f o r   d e f a u l t 
g a t e w a y   u n l e s s   y o u   k n o w   w h a t   y o u   a r e   d o i n g .  Removing  the  default  route  will  render  the  Internet 
unreachable.
7.3.4  Viewing the Static Routing Table
Al l   IP- e n a b l e d   co mp u te rs   a n d   ro u te r s  m a i n ta i n   a   ta b l e   o f  IP 
addresses that are commonly accessed by their users. For each of 
these destination IP addresses, the table lists the IP address of the 
fi rst  hop  the  data  should  take.  This  table  is  known  as  the  deviceʼs 
routing table. 
To  view  the  RX3042Hʼs  routing  table,  click  the  Advanced  ->Static 
Route   menu.  The  Routing  Table  displays  at  the  upper  half  of  the 
Static Route Confi guration page, as shown in Figure 7.2:
The Routing Table displays a row for each existing route containing 
t h e   I P  a d d r e s s   o f   t h e   d e s t i n a t i o n   n e t w o r k ,   s u b n e t   m a s k   o f 
destination  network  and  the  IP  of  the  gateway  that  forwards  the 
traffi c.