Cisco CISCO876-SEC-I-K9 Configuration Guide - Page 42

Con Network Address Translation

Get Cisco CISCO876-SEC-I-K9 - 876 Security Bundle Router PDF manuals and user guides
UPC - 882658021800
View all Cisco CISCO876-SEC-I-K9 manuals
Add to My Manuals
Save this manual to your list of manuals

Page 42 highlights

Configure Network Address Translation Chapter 3 Configuring PPP over Ethernet with NAT Configure Network Address Translation Network Address Translation (NAT) translates packets from addresses that match a standard access list, using global addresses allocated by the dialer interface. Packets that enter the router through the inside interface, packets sourced from the router, or both are checked against the access list for possible address translation. You can configure NAT for either static or dynamic address translations. Perform these steps to configure the outside Fast Ethernet WAN interface with dynamic NAT, beginning in global configuration mode: Step 1 Command ip nat pool name start-ip end-ip {netmask netmask | prefix-length prefix-length} Purpose Creates pool of global IP addresses for NAT. Example: Router(config)# ip nat pool pool1 192.168.1.0 192.168.2.0 netmask 255.255.252.0 Router(config)# Step 2 Step 3 ip nat inside source {list access-list-number} Enables dynamic translation of addresses on the {interface type number | pool name} [overload] inside interface. Example 1: Router(config)# ip nat inside source list 1 interface dialer 0 overload or Example 2: Router(config)# ip nat inside source list acl1 pool pool1 The first example shows the addresses permitted by the access list 1 to be translated to one of the addresses specified in the dialer interface 0. The second example shows the addresses permitted by access list acl1 to be translated to one of the addresses specified in the NAT pool pool1. For details about this command and additional parameters that can be set, as well as information about enabling static translation, see the Cisco IOS IP Command Reference, Volume 1 of 4: Addressing and Services. interface type number Example: Router(config)# interface vlan 1 Router(config-if)# Enters configuration mode for the VLAN (on which the Fast Ethernet LAN interfaces [FE0-FE3] reside) to be the inside interface for NAT. Step 4 ip nat {inside | outside} Example: Router(config-if)# ip nat inside Router(config-if)# Identifies the specified VLAN interface as the NAT inside interface. For details about this command and additional parameters that can be set, as well as information about enabling static translation, see the Cisco IOS IP Command Reference, Volume 1 of 4: Addressing and Services. Cisco 850 Series and Cisco 870 Series Access Routers Software Configuration Guide 3-6 OL-5332-01

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
  • 57
  • 58
  • 59
  • 60
  • 61
  • 62
  • 63
  • 64
  • 65
  • 66
  • 67
  • 68
  • 69
  • 70
  • 71
  • 72
  • 73
  • 74
  • 75
  • 76
  • 77
  • 78
  • 79
  • 80
  • 81
  • 82
  • 83
  • 84
  • 85
  • 86
  • 87
  • 88
  • 89
  • 90
  • 91
  • 92
  • 93
  • 94
  • 95
  • 96
  • 97
  • 98
  • 99
  • 100
  • 101
  • 102
  • 103
  • 104
  • 105
  • 106
  • 107
  • 108
  • 109
  • 110
  • 111
  • 112
  • 113
  • 114
  • 115
  • 116
  • 117
  • 118
  • 119
  • 120
  • 121
  • 122
  • 123
  • 124
  • 125
  • 126
  • 127
  • 128
  • 129
  • 130
  • 131
  • 132
  • 133
  • 134
  • 135
  • 136
  • 137
  • 138
  • 139
  • 140
  • 141
  • 142
  • 143
  • 144
  • 145
  • 146
  • 147
  • 148
  • 149
  • 150
  • 151
  • 152
  • 153
  • 154
  • 155
  • 156
  • 157
  • 158
  • 159
  • 160
  • 161
  • 162
  • 163
  • 164
  • 165
  • 166
  • 167
  • 168
  • 169
  • 170
  • 171
  • 172
  • 173
  • 174
  • 175
  • 176
  • 177
  • 178
  • 179
  • 180
  • 181
  • 182
  • 183
  • 184
  • 185
  • 186
  • 187
  • 188
  • 189
  • 190
  • 191
  • 192
  • 193
  • 194
  • 195
  • 196
3-6
Cisco 850 Series and Cisco 870 Series Access Routers Software Configuration Guide
OL-5332-01
Chapter 3
Configuring PPP over Ethernet with NAT
Configure Network Address Translation
Configure Network Address Translation
Network Address Translation (NAT) translates packets from addresses that match a standard access list,
using global addresses allocated by the dialer interface. Packets that enter the router through the inside
interface, packets sourced from the router, or both are checked against the access list for possible address
translation. You can configure NAT for either static or dynamic address translations.
Perform these steps to configure the outside Fast Ethernet WAN interface with dynamic NAT, beginning
in global configuration mode:
Command
Purpose
Step 1
ip nat pool
name start-ip end-ip
{
netmask
netmask
|
prefix-length
prefix-length
}
Example:
Router(config)#
ip nat pool pool1
192.168.1.0 192.168.2.0 netmask
255.255.252.0
Router(config)#
Creates pool of global IP addresses for NAT.
Step 2
ip nat inside source
{
list
access-list-number
}
{
interface
type number |
pool
name
} [
overload
]
Example 1:
Router(config)#
ip nat inside source list
1
interface dialer 0 overload
or
Example 2:
Router(config)#
ip nat inside source list
acl1 pool
pool1
Enables dynamic translation of addresses on the
inside interface.
The first example shows the addresses permitted
by the access list
1
to be translated to one of the
addresses specified in the dialer interface
0
.
The second example shows the addresses
permitted by access list
acl1
to be translated to one
of the addresses specified in the NAT pool
pool1
.
For details about this command and additional
parameters that can be set, as well as information
about enabling static translation, see the
Cisco IOS IP Command Reference, Volume 1 of 4:
Addressing and Services
.
Step 3
interface
type number
Example:
Router(config)#
interface
vlan 1
Router(config-if)#
Enters configuration mode for the VLAN (on
which the Fast Ethernet LAN interfaces
[FE0–FE3] reside) to be the inside interface for
NAT.
Step 4
ip nat
{
inside
|
outside
}
Example:
Router(config-if)#
ip nat inside
Router(config-if)#
Identifies the specified VLAN interface as the
NAT inside interface.
For details about this command and additional
parameters that can be set, as well as information
about enabling static translation, see the
Cisco IOS IP Command Reference, Volume 1 of 4:
Addressing and Services
.