Sponsored Content
Full Discussion: iptables in a NAT scenario
Special Forums Cybersecurity iptables in a NAT scenario Post 302808861 by DGPickett on Friday 17th of May 2013 04:12:49 PM
Old 05-17-2013
IPTables can do NAT, but here someone else does it for you, so all addresses are inside addresses or real remote Internet addresses.

NAT/PAT generaly hides inside addresses, not Internet remote addresses.

I suppose you could write or configure a NAT/PAT to forward packets to you with the remote address changed to ones of the NAT host, and when packets return to the NAT host, it knows which host-port become what remote host-port. That ensures the NAT/PAT packets route back to the NAT/PAT host, but seems a waste of time. Usually the NAT/PAT packets have the remote Internet client or server host and port, it is the inside addresses that are protected, and it just does not work if your routing sends response packets to a different firewall. Usually inside addresses are either registered Internet ready, unroutable like 10.*.*.* or stolen/made-up. I suppose if you have stolen, you need to ensure the real ones are serviced and not a threat!
This User Gave Thanks to DGPickett For This Post:
 

10 More Discussions You Might Find Interesting

1. IP Networking

Ftp'ing thru a Iptables NAT Masquerade

Greetings to all. My new firewall is giving me one hell of a problem. I'm running iptables and masquerading my intranet thru NAT. But here is the problem. Whenever I try to FTP to a server outside of my lan I get a 500 illegal port error. I've come to the conclusion that NAT is... (2 Replies)
Discussion started by: phrater
2 Replies

2. UNIX for Advanced & Expert Users

iptables internal NAT with two public IP

Hello Guys, I have a debian machine that work as a firewall (iptables + squid 2.6) with two physical interfaces: eth0 (public interface) and eth1 (internal interface LAN). I have created an alias eth1:1 in order to have two subnets on same physical interface: cat/etc/network/interfaces auto... (0 Replies)
Discussion started by: sincity2006
0 Replies

3. IP Networking

How to configure Full Cone NAT using iptables ?

Hi Experts; I want to find the right iptables commands combination to address the following need: - NEs are NATed thru the linux box (using iptables) towards the WAN cloud, where the NTP servers are situated. - In order to achieve redundancy, the NTP Servers are in a load balancing cluster... (0 Replies)
Discussion started by: lvl1s7a
0 Replies

4. Debian

Iptables Nat forward port 29070

Hello, the Nat and the forward worked on my debian server up to the reboot of machines. The following rules*: /sbin/iptables -t nat -A PREROUTING -p tcp -i eth2 -d xxx.xxx.xxx.xxx --dport 29070 -j DNAT --to-destination 10.0.1.7:29070 /sbin/iptables -A FORWARD -p tcp -i eth2 -o eth0 -d... (0 Replies)
Discussion started by: titoms
0 Replies

5. IP Networking

iptables NAT prerouting & postrouting

Good morning, I'm a newbie of iptables and as far as I've seen on tutorials on the Internet it seems that both prerouting and postrouting NAT chains are undergone both by a packet that goes from an internal LAN to the Internet and of a one that goes in the opposite direction (from the Internet to... (0 Replies)
Discussion started by: giac85
0 Replies

6. Red Hat

NAT Loopback and iptables

Hello, please can you help and explain me. I have two servers. Both are RHEL6. I use the first one like router and the second one for apache. Router forwards 80 port on the second server and I can open that from the internet (mysite.com, for example). But I can not open mysite.com if i try to... (0 Replies)
Discussion started by: 6765656755
0 Replies

7. IP Networking

Nat and packet limits with iptables

Hi all, I have a following situation: - I want certain source IPs to be natted to a different destination IP and Port. Following is how I am achieving it: /usr/local/sbin/iptables -t nat -A PREROUTING -p tcp -s 192.168.10.12 --dport 1500 -j DNAT --to-destination 192.168.10.20:2000 ... (3 Replies)
Discussion started by: ahmerin
3 Replies

8. IP Networking

Debugging NAT / prerouting issues (iptables)

Hello, Recently I discovered an issue with packet routing in the latest Android releases (4.4+ KitKat & Lollipop). It seems that the problem Android specific, but essentially it comes from the Linux kernel. I already filed a bug report to Google. You can see the details by searching for... (0 Replies)
Discussion started by: Vladislav
0 Replies

9. IP Networking

NAT via iptables - Won't work!!

Hi guys I'm running on debian on a small embedded system. I have a ppp interface that is connected to the internet (and works). My unit also has wifi access point (which works and I can connect to it). I want to allow connections to the wifi to be able to use the internet from ppp0... (1 Reply)
Discussion started by: alirezan1
1 Replies

10. Cybersecurity

Openvpn nat and iptables

good day good people hi first to tell that firewall and vpn is working as expected, but I notice something strange. I have host system 11.11.11.11(local ip) firewall is blocking everything except port to vpn. I have vpn on virtualized system 22.22.22.22 (CentOS both host and virtual). ... (0 Replies)
Discussion started by: end
0 Replies
IPTABLES-SAVE(8)                                                  iptables 1.6.1                                                  IPTABLES-SAVE(8)

NAME
iptables-save -- dump iptables rules to stdout ip6tables-save -- dump iptables rules to stdout SYNOPSIS
iptables-save [-M modprobe] [-c] [-t table] ip6tables-save [-M modprobe] [-c] [-t table] DESCRIPTION
iptables-save and ip6tables-save are used to dump the contents of IP or IPv6 Table in easily parseable format to STDOUT. Use I/O-redirect- ion provided by your shell to write to a file. -M, --modprobe modprobe_program Specify the path to the modprobe program. By default, iptables-save will inspect /proc/sys/kernel/modprobe to determine the exe- cutable's path. -c, --counters include the current values of all packet and byte counters in the output -t, --table tablename restrict output to only one table. If not specified, output includes all available tables. BUGS
None known as of iptables-1.2.1 release AUTHORS
Harald Welte <laforge@gnumonks.org> Rusty Russell <rusty@rustcorp.com.au> Andras Kis-Szabo <kisza@sch.bme.hu> contributed ip6tables-save. SEE ALSO
iptables-apply(8),iptables-restore(8), iptables(8) The iptables-HOWTO, which details more iptables usage, the NAT-HOWTO, which details NAT, and the netfilter-hacking-HOWTO which details the internals. iptables 1.6.1 IPTABLES-SAVE(8)
All times are GMT -4. The time now is 09:00 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy