Isn't NAT a MUST when a LAN uses rfc 1918 private IPs?

Posted by aks on Server Fault See other posts from Server Fault or by aks
Published on 2010-04-07T15:53:11Z Indexed on 2010/04/07 16:03 UTC
Read the original article Hit count: 315

Filed under:

nat

|

ipv4

Isn't NAT a MUST when a LAN uses rfc 1918 private IPs? Can an organization assign its hosts with private IPs and still communicate with the external world without NAT?

how can an internal host with a private IP (say 10.1.1.1) communicate with external world without NAT? I mean, how can the reply/response packet from the external world reach the original source as the packet with Dest IP = 10.1.1.1 will get lost as it can not be routed as many organizations can use the same IP.

Why doesn't rfc 1918 (Address Allocation for Private Internets) make any mention of NAT?

© Server Fault or respective owner

Related posts about nat

Cisco 881 losing NAT NVI translation config after reload

as seen on Server Fault - Search for 'Server Fault'
This is a weird one, so I'll try to explain in as much detail as I can so I'm giving the whole picture. As I've mentioned in my other questions, I'm in the process of setting up a new Cisco 881 as my WAN router and NAT firewall. I'm facing an issue where NAT NVI rules that I have configured are not… >>> More
IPtables AWS EC2 NAT/Reverse NAT - For Reverse Proxy style setup but with IPtables

as seen on Server Fault - Search for 'Server Fault'
I was thinking initially needing to do a reverse proxy or something so I could get some SSL/TLS traffic look like it is being terminated at a server and IP address in the AWS cloud, and then that traffic is forwarded onto our actual web servers that aren't in the cloud... I've not done much iptables… >>> More
asterisk/freeswitch in nat/no-nat setup

as seen on Server Fault - Search for 'Server Fault'
hi, my current setup - i use bunch of sip hard-phones around few offices. all devices have two sip accounts configured - one on internal sip proxy [for calls between the branches], another - at 3rd party voip providers [ since it's in different countries - those are different providers, but that's… >>> More
Problem with setup VPN in Ubuntu Server 12.04

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I have a problem with setup VPN server on my Ubuntu VPS, here is my server environments: Ubuntu Server 12.04 x86_64 xl2tpd 1.3.1+dfsg-1 pppd 2.4.5-5ubuntu1 openswan 1:2.6.38-1~precise1 After install software and configuration: ipsec verify Checking your system to see if IPsec got installed and… >>> More
Problem with setup VPN on Ubuntu Server 12.04

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I have a problem with setup VPN server on my Ubuntu VPS, here is my server environments: Ubuntu Server 12.04 x86_64 xl2tpd 1.3.1+dfsg-1 pppd 2.4.5-5ubuntu1 openswan 1:2.6.38-1~precise1 After install software and configuration: ipsec verify Checking your system to see if IPsec got installed and… >>> More

Related posts about ipv4

Static IPv4 and dynamic IPv6 on same interface

as seen on Server Fault - Search for 'Server Fault'
I am trying to set up a CentOS 5.4 box to use a static IPv4 address, while getting a dynamic IPv6 address at boot time. I have only one interface, apart from the loopback interface, eth0. It has a static v4 and internet connectivity (I can SSH in). However, it doesn't get an IPv6 by default. I have… >>> More
Use UdpClient with IPv4 and IPv6?

as seen on Stack Overflow - Search for 'Stack Overflow'
A little while ago I created a class to deal with my LAN networking programs. I recently upgraded one of my laptops to windows 7 and relized that windows 7 (or at least the way I have it set up) only supports IPv6, but my desktop is still back in the Windows xp days, and only uses IPv4. The class… >>> More
Scrubbing IPv4 dotted-quad addresses in SQL

as seen on Stack Overflow - Search for 'Stack Overflow'
Given a table containing dotted quad IPv4 addresses stored as a VARCHAR(15), for example: ipv4 -------------- 172.16.1.100 172.16.50.5 172.30.29.28 what's a convenient way to SELECT all "ipv4" fields with the final two octets scrubbed, so that the above would become: ipv4 ------------ … >>> More
Gearman too many processes issue

as seen on Server Fault - Search for 'Server Fault'
I use Net_Gearman from PECL, Gearmand 1.1.11 and Gearman Manager. Every time I add background job, I can see new worker listed with no Function, nor Id in Ggearman-Monitor: If I add many messages in the bash loop, after some time it becomes very slow. for i in $(seq 0 9999); do php Client.php… >>> More
Proxy / Squid 2.7 / Debian Wheezy 6.7 / lots of TCP Timed-out

as seen on Server Fault - Search for 'Server Fault'
i'm facing a lot of TCP timed-out on a busy cache server and here below my sysctl.conf configuration as well as an output of "netstat -st" Kernel 3.2.0-4-amd64 #1 SMP Debian 3.2.57-3 x86_64 GNU/Linux Any advice or help would be highly appreciated #################### Sysctl.conf cat /etc/sysctl… >>> More