Re: NAT not using all IP NAT

From: jmaiman@ebnetworks.com
Date: Wed Feb 21 2001 - 14:57:42 EST


RafaReta,

     By putting the overload at the end of the statement "ip nat inside
source list 1 pool fuera overload" you are configuring your router for Port
Address Translation (PAT). What this does is use a single IP address as
the global address with different tcp/udp port numbers to represent all of
your local IP addresses. Your NAT pool is defined for the subnet
168.233.15.136/30. The 168.233.15.136 is the network number for this
subnet and is not a valid IP address for a host. Also 168.233.15.139 is
the broadcast address for this subnet and is also not a valid IP address
for a host. So, 168.233.15.137 is the first valid adddress for the subnet
and hence PAT translates all local IP address to this global address.

                                   --Jon

"Rafael A. Reta Rodriguez" <rafareta@icave.com.mx> on 02/21/2001 10:15:25
AM

To: cisco-nsp@puck.nether.net
cc:

Subject: NAT not using all IP NAT

I want to make NAT with 168.233.15.136 to 139 global inside address but NAT
only use the 168.233.15.137, this is part of the configuration:

BTW I use a Cisco 3640

version 12.0
interface Ethernet0/0
  ip nat inside
interface Serial1/0:7
  ip nat outside
ip nat pool fuera 168.233.15.136 168.233.15.139 netmask 255.255.255.252
ip nat inside source list 1 pool fuera overload
access-list 1 permit 10.12.1.229
access-list 1 permit 10.12.0.0 0.0.255.255

This a chomp of the show ip nat translation:
Pro Inside global      Inside local       Outside local      Outside global
tcp 168.233.15.137:1035 10.12.1.229:2183  207.248.1.61:80
207.248.1.61:80
tcp 168.233.15.137:1257 10.12.8.144:1224  200.52.208.19:110
200.52.208.19:110
tcp 168.233.15.137:1228 10.12.1.12:1518   216.140.160.8:80
216.140.160.8:80
tcp 168.233.15.137:1073 10.12.5.223:1849  207.46.216.74:6667
207.46.216.74:6667
tcp 168.233.15.137:2476 10.12.1.43:2476   64.225.34.216:80
64.225.34.216:80
tcp 168.233.15.137:3041 10.12.1.43:3041   207.200.89.193:80
207.200.89.193:80
tcp 168.233.15.137:2082 10.12.8.134:1348  204.178.112.170:80
204.178.112.170:80
tcp 168.233.15.137:1260 10.12.1.12:1513   216.140.160.8:80
216.140.160.8:80
tcp 168.233.15.137:1417 10.12.5.195:1078  208.239.159.17:80
208.239.159.17:80

And never uses 168.233.15.136 -138 - 139
What is wrong?

Thanks in advance

RafaReta



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