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* DNAT problem
@ 2002-11-19  8:07 HCLFM
  2002-11-21 21:53 ` Rahul Jadhav
  0 siblings, 1 reply; 41+ messages in thread
From: HCLFM @ 2002-11-19  8:07 UTC (permalink / raw)
  To: netfilter

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Hi, 

I have Redhat Linux 7.1 Kernel version 2.4.2-2. 
with iptables v1.2.7 . 

This nat module is loaded with ip_tables module 
iptable_nat 16160 0 (autoclean) [ipt_MASQUERADE] 

I'm trying to setup DNAT for port forwarding as per iptables documents . I have ip forwarding enabled. I want port forward from external interface to a internal server . 

But the setup is not working , I have tried with all possible styles of PREROUTING chain. 
When I connect to external IP address with the particular port , I get a "connection refused" error. But the software port forwarders work perfectly. I feel that the problem lies in proxy ARP support of the kernel. 

Any suggestions ? 

regards, 
U.SivaKumar 

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^ permalink raw reply	[flat|nested] 41+ messages in thread
[parent not found: <45227670.8040702@mail.nankai.edu.cn>]
[parent not found: <4521C6A3.1040902@mail.nankai.edu.cn>]
* DNAT problem
@ 2006-10-02  8:00 Stefan Friedel
  2006-10-02  8:25 ` Marco Berizzi
  0 siblings, 1 reply; 41+ messages in thread
From: Stefan Friedel @ 2006-10-02  8:00 UTC (permalink / raw)
  To: netfilter

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Good Morning,
I have a problem after switching from an old 2.4.x installation to 2.6.17.3 - scenario:
- computer pool with central server, central server visible in the internet
- several nodes, two of them access nodes, private network
- the two access nodes in the pool get all external ssh connections via a rule on the central server

iptables -t nat -A PREROUTING -p tcp -i eth3 -d <external IP> -j DNAT --dport 22 --to-destination <firstprivip>-<lastprivip>

This worked fine with 2.4.29 (server+nodes). But after switching to 2.6 round
robin is no longer working: only the node <lastprivip> is used. Changing the
rule and using the --to-destination <firstprivip> --to-destination <lastprivip>
does not work at all: iptables is complaining about invalid arguments.

iptables on the server is v1.2.11, Debian sarge, 2.6.17.3

Any hint? Did I miss some changes in the behavior of netfilter/iptables?

Thanks and Regards, Stefan Friedel
-- 
Zentrale Dienste - Interdisziplinäres Zentrum für Wissenschaftliches
Rechnen der Universität Heidelberg - IWR - INF 368, 69120 Heidelberg
stefan.friedel@iwr.uni-heidelberg.de  Tel +49 6221 54-8240 Fax -5224
IWR: www.iwr.uni-heidelberg.de          HELICS: www.helics.uni-hd.de

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^ permalink raw reply	[flat|nested] 41+ messages in thread
* DNAT problem
@ 2006-07-08 21:00 Antonio Di Bacco
  0 siblings, 0 replies; 41+ messages in thread
From: Antonio Di Bacco @ 2006-07-08 21:00 UTC (permalink / raw)
  To: netfilter

I receive on an interface (eth0, NOARP , ipaddr: 192.168.0.20 ) a tcp packet 
in this way (I have dumped it with tcpdump):

SRC: 192.168.0.21:6000 
DST: 192.168.0.21:80

I have an iptables rule:

iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j DNAT 
--to-destination 192.168.0.20:80

Why my web server listening on eth0 doesn't receive it?

Thank you,
Antonio.


^ permalink raw reply	[flat|nested] 41+ messages in thread
* dnat problem
@ 2005-01-22 15:59 Pablo Allietti
  2005-01-22 19:45 ` Jason Opperisano
  0 siblings, 1 reply; 41+ messages in thread
From: Pablo Allietti @ 2005-01-22 15:59 UTC (permalink / raw)
  To: netfilter

hi all

i have a problem with dnat i have this struc.


		|
		|internet
		|
		Firewall 200.20.43.2
		|
		|
		|
		Server 192.168.1.143


and i have this rule in the firewall.

iptables  -t nat -A PREROUTING -i eth0 -p tcp --dport 2244  -j DNAT
--to-destination 192.168.1.143:22

i supouse this rule make a dnat to server 192.... to ssh but nothing
happends

i do ssh -p2244 200.20.43.2  but nothing respond

what i miss ? :(


thnks all!!


-- 


Pablo Allietti
LACNIC
--------------



^ permalink raw reply	[flat|nested] 41+ messages in thread
* DNAT problem
@ 2004-06-10 11:03 Paul M. Goorskis
  0 siblings, 0 replies; 41+ messages in thread
From: Paul M. Goorskis @ 2004-06-10 11:03 UTC (permalink / raw)
  To: netfilter

Hello list!

Problem: forward from branch office address 10.1.12.146 to 192.168.130.15 on internal network
I'm stuck
It's not DNAT'ing...
Main office using 192.168.0.0/16 for internal needs and 10.23.17.0/24 to communicate with branch office
Branch office using 10.0.0.0/8

versions:
iptables v1.2.7a
kernel 2.4.20

                                                +-------------+          +-----------+
                                                |BRANCH VPN   +----------+10.1.12.146|
                                                |10.23.254.249|eth1      +-----------+
                                                +----+--------+
                                                     |eth0
                                      +--------+     |
                                      |Internet+-----+
                                      +--------+
                                          |
                                          |eth0 (213.175.70.195)
+---------------+                  eth2+------+            +------------------+
|192.168.130.15 +----------------------+ROUTER+------------+VPN 213.175.70.198|
+---------------+                      +------+eth1        |    10.23.254.250 |
                                                           |   10.23.17.0/0   |
                                                           +------------------+

BRANCH VPN:
route add -net 10.23.17.0/24 gw 10.23.254.250 dev tunl1

VPN:
route add -net 10.23.17.0/24 gw ROUTER
route add -net 10.0.0.0/8 gw 10.23.254.249 dev tunl1

ROUTER:
route add -net 10.0.0.0/8 gw VPN
iptables -t nat -A PREROUTING -i eth1 -s 10.1.12.146 -d 10.23.17.99 -j DNAT --to-destination 192.168.130.15
iptables -A FORWARD -s 10.1.12.146 -d 192.168.130.15 -i eth1 -o eth2 -j ACCEPT
iptables -A FORWARD -d 10.1.12.146 -s 192.168.130.15 -o eth1 -i eth2 -j ACCEPT

Ok, here it goes:
packet started traveling from 10.1.12.146 with DST=10.23.17.99
packet arrived at BRANCH VPN with TTL=27
packet arrived at VPN with TTL=26
packet arrived at ROUTER with TTL=25
and here comes troubles... instead of DNAT'ing connection to 192.168.130.15 and routing 
it via eth2 it routes it's not DNAT'ing but sending packet as if it final destination
is 10.23.17.99 via eth1 to VPN box. Not a big surprise that VPN box routes this packet
back to ROUTER. Finaly ping-pong ends at ROUTER with TTL=1 going nowhere. What i'm doing wrong?
I got bunch of similar rules working OK. Just stuck with this one. 
Help! :)

Thank you!




^ permalink raw reply	[flat|nested] 41+ messages in thread
* DNAT problem
@ 2004-05-29 15:25 Patrick Leslie Polzer
  2004-05-29 15:36 ` Alexis
  0 siblings, 1 reply; 41+ messages in thread
From: Patrick Leslie Polzer @ 2004-05-29 15:25 UTC (permalink / raw)
  To: netfilter


Hello again,

a DNAT problem is coming up.
My firewall setup (simplified for testing) is currently as follows:


### <snip> ###

##### FILTER table #####
# policies
$ipt -P FORWARD ACCEPT
$ipt -P   INPUT ACCEPT
$ipt -P  OUTPUT ACCEPT

$ipt -F
$ipt -F FORWARD
$ipt -F   INPUT
$ipt -F  OUTPUT


##### NAT table #####
# flush chains
$ipt -t nat -F  PREROUTING
$ipt -t nat -F POSTROUTING
$ipt -t nat -F      OUTPUT

# masquerading on ppp0 and vortex
$ipt -t nat -A POSTROUTING -o   ppp0 -j MASQUERADE
$ipt -t nat -A POSTROUTING -o vortex -j MASQUERADE

# dnat
$ipt -t nat -A PREROUTING -i ppp0 -p tcp --dport 80 -j DNAT --to-destination 192.168.35.191:80

### </snip> ###


The last line is working with

--dport 8080

but isn't with

--dport 80

What's going on there?


Kind regards,

Leslie


^ permalink raw reply	[flat|nested] 41+ messages in thread
* [Fwd: Re: DNAT Problem]
@ 2004-04-27  5:57 test
  2004-04-27  7:20 ` DNAT Problem Rob Sterenborg
  0 siblings, 1 reply; 41+ messages in thread
From: test @ 2004-04-27  5:57 UTC (permalink / raw)
  To: netfilter

Hi All

I am facing a problem with DNAT and the detail of my problem is as follows :

I have an email server running behind the firewall serving POP3 & SMTP.
Now all requests DNAT from the firewall are logged as if received from the
firewall itself and thus considered as trusted ip. I want all the DNAT
requests to be logged as received real source ip and not from firewall ip.

Please find attach a copy of my firewall script so that you all would be
able to suggest me the required changes. (optional : Any suggestion to
make it more secure)

++++++++++++++++++++++++++++++++++++

#!/bin/bash

# Flush All IPTABLE Rules
iptables -F INPUT
iptables -F OUTPUT
iptables -F FORWARD
iptables -t nat -F PREROUTING
iptables -t nat -F POSTROUTING
iptables -t nat -F OUTPUT

# Default Policy Rules
iptables -P INPUT DROP
iptables -P OUTPUT ACCEPT
iptables -P FORWARD ACCEPT
iptables -t nat -P PREROUTING ACCEPT
iptables -t nat -P POSTROUTING ACCEPT
iptables -t nat -P OUTPUT ACCEPT

# Allow only incoming connections that we establish first
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

# Rules for lo
iptables -A INPUT -s 127.0.0.0/255.0.0.0 -i ! lo -j DROP

# Rules for eth0 - LAN
iptables -A INPUT -i eth0 -p tcp --dport 22 -j ACCEPT

# Rules for eth1 - Internet
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
iptables -A INPUT -i eth1 -p icmp -j DROP
iptables -A INPUT -i eth1 -p tcp -m tcp ! --tcp-flags SYN,RST,ACK SYN -j
ACCEPT

# SSH
iptables -A INPUT -i eth1 -p tcp --dport 22 -j ACCEPT

# Email Server Access From Outside
# SMTP
iptables -t nat -A PREROUTING -i eth1 -p tcp --dport 25 -j DNAT --to
192.168.0.6:25

# Web
iptables -t nat -A PREROUTING -i eth1 -p tcp --dport 80 -j DNAT --to
192.168.0.190:80

# POP3
iptables -t nat -A PREROUTING -p tcp -i eth1 --dport 110 -j DNAT --to
192.168.0.6:110

# WebMail
iptables -t nat -A PREROUTING -i eth1 -p tcp --dport 8000 -j DNAT --to
192.168.0.6:80

iptables -A INPUT -i eth1 -j DROP

++++++++++++++++++++++++++++++++++++


Regards

Joel

---------------------------- Original Message ----------------------------
Subject: Re: DNAT Problem
From:    test@seaconindia.com
Date:    Fri, April 23, 2004 5:52 pm
To:      netfilter@lists.netfilter.org
--------------------------------------------------------------------------

Hi Antony

> On Thursday 22 April 2004 7:18 pm, test@seaconindia.com wrote:
>
>> > > iptables -t nat -A PREROUTING -i eth1 -p tcp --dport 25 -j DNAT
--to 192.168.0.6:25
>> >
>> > I don't believe that can be your complete ruleset.
>> >
>> > I see nothing wrong with the above rule as it stands, however on its
>> own
>> > it's not much good - you need a FORWARD rule to allow packets through
>> to
>> > the mail server as well.
>>
>> Can you give me an example of the forward rule set.
>
> iptables -A FORWARD -d a.b.c.d -p tcp --dport 25 -j ACCEPT
>
> where a.b.c.d is the real (internal) IP address of your mail server.
>

I modified my script as suggested by you but no luck

>> > Anyway, I thought (I may be mistaken) that the problem was not with
>> the
>> > inbound DNAT, but with SNAT?
>
> I repeat the statement immediately above.
>
>> Or shall I attach my complete bash script ? (is it ok ?)
>
> Please do post the smallest ruleset which demonstrates the problem (ie
it allows access to your internal mailserver, but all accesses appear to
be from
> the firewall's IP address).
>

Please find below the SMTP log of my email server

++++++++++++++++++
@4000000040890aad255365a4 tcpserver: pid 30530 from 192.168.0.151
@4000000040890aad2a6f2e9c tcpserver: ok 30530
mail.localmail.com:192.168.0.6:25 :192.168.0.151::1592
++++++++++++++++++

Please note
Firewall IP = 192.168.0.151
Email Server IP = 192.168.0.6

Regards

Joel






^ permalink raw reply	[flat|nested] 41+ messages in thread
* DNAT Problem
@ 2004-04-19  5:07 test
  2004-04-19 13:43 ` Joel Newkirk
  0 siblings, 1 reply; 41+ messages in thread
From: test @ 2004-04-19  5:07 UTC (permalink / raw)
  To: netfilter

Hi All

I am new to Iptables & Firewall. I have 2 servers (web & email) running
behind firewall. I have DNAT rule on my firewall, so any request hitting
on port 25, 80, 110 are DNAT to internal servers. Inturn my internal
servers (web & email) feel these requests were received from firewall ie
internal ip and can be trusted.

I want these DNAT request to be forward with their original ip address and
not as coming from firewall ip.

Please advice my firewall rule is as follows :

iptables -t nat -A PREROUTING -p tcp -i eth1 --dport 25 -j DNAT --to
192.168.0.175:25

Regards

Joel


^ permalink raw reply	[flat|nested] 41+ messages in thread
* DNAT problem
@ 2003-03-30 14:58 Alexandru Coseru
  2003-03-30 15:41 ` Joel Newkirk
  0 siblings, 1 reply; 41+ messages in thread
From: Alexandru Coseru @ 2003-03-30 14:58 UTC (permalink / raw)
  To: netfilter

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hello.. I have the folowing problem...  I have a linux gateway with the external IP x.x.x.x  and internal Ip 192.168.0.1.    I want to make a DNAT and mask a conection from the external IP , forwarded to one of my lan's computer , and the lan computer to see it as 192.168.0.1 , not x.x.x.x



Example:    If a packet comes from linux.org to a specific port (let's say 1345) ,   i want to forward it to a lan computer ( 192.168.0.5) , and mask that connection in a way that 192.168.0.5 sees the packet comes from 192.168.0.1 , and not from linux.org      (it's exactly as masquarading , but in reverse way...)



                                                                                                                                        Alex

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^ permalink raw reply	[flat|nested] 41+ messages in thread
* DNAT problem
@ 2002-11-27 19:28 Geoff Silver
  0 siblings, 0 replies; 41+ messages in thread
From: Geoff Silver @ 2002-11-27 19:28 UTC (permalink / raw)
  To: netfilter

I'll preface this by saying I'm not subscribed to the list, so if anyone
who can help would CC me, that would be appreciated.  Thanks!

I have a 3-way firewall doing DNAT from a public address space (66.243
net) to a private address space (10.102 net).  Everything works, except
when I'm on the DMZ and try to reach another DMZ machine through it's
public IP.  The requests traverse the DNAT rule which *should* translate
them to their 10.102 destination address (and it works from my LAN or from
the internet), but instead the address isn't rewritten.

Example:  public IP is 66.243.73.184 which is NAT'd to 10.102.1.2.  If I
tcpdump on 10.102.1.2 and use a web browser from an internet host
(somewhere else in the world), I see something like:

14:25:00.353543 152.163.190.1.38300 > 10.102.1.2.80: S
3550573715:3550573715(0) win 24820 <nop,nop,sackOK,mss 1412> (DF) [tos
0x10]
14:25:00.353578 10.102.1.2.80 > 152.163.190.1.38300: S
1480002886:1480002886(0) ack 3550573716 win 15532 <mss
1412,nop,nop,sackOK> (DF)
14:25:00.423200 152.163.190.1.38300 > 10.102.1.2.80: . ack 1 win 25416
(DF) [tos 0x10]
14:25:01.333833 152.163.190.1.38300 > 10.102.1.2.80: P 1:6(5) ack 1 win
25416 (DF) [tos 0x10]

However, if I tcpdump and try the same thing from the host itself, I see:

13:59:42.698619 10.102.1.2.3024 > 66.243.73.184.80: S
4167737472:4167737472(0) win 16060 <mss 1460,sackOK,timestamp 25440395
0,nop,wscale 0> (DF) [tos 0x10]

Since I can look at the number of packets sent over the DNAT rule via
'iptables -t nat -v -L' and *see* the number of packets changing
corresponding to the number sent (and the intervals sent), I'm *sure* the
packets are traversing that rule, but not getting NAT'ed.  Does anyone
have any ideas *why* this might be happening?  Is this a bug?  Does anyone
perhaps have a workaround for it?  I could run split-DNS (DNS-views) or IP
alias the server, but it's a kludge, and I really *want* my firewall to do
the translation right.

Thanks!



^ permalink raw reply	[flat|nested] 41+ messages in thread
* dnat problem
@ 2002-05-21 20:53 support
  2002-06-13 17:28 ` Antony Stone
  0 siblings, 1 reply; 41+ messages in thread
From: support @ 2002-05-21 20:53 UTC (permalink / raw)
  To: netfilter

hello all,
this is my first time posting to this board.  i am having trouble
with my iptables rules.  my configuration consists of a linux
router as the main network gateway and firewall providing NAT and
ipsec.  i have compiled kernel 2.4.17 with freeS/WAN version
1.91.   i have a source nat rule set up so my non-routable
addresses can use the gateway to reach the internet.  i did not use
the MASQUERADE target.

here is my Source nat rule

iptables -t nat -A POSTROUTING -s 192.168.1.0/24 -o eth1 -j SNAT --to
w.x.y.z

I also have some destination nat rules set up.
iptables -t nat -A PREROUTING -d w.x.y.a -p tcp -m tcp --dport 80 -j
DNAT --to-destination 192.168.1.48

There are about 5 additional dnat rules that are basically the same
so I won't list them.

the problem i am having is that the internal private subnet
(192.168.1.0/24) on my network is unable to bring up sites that
have been setup using dnat rules.  external users have no problem
viewing the sites i have set up dnat rules for.

any help would be greatly appreciated.

thanks

---
Ollie Gallardo



^ permalink raw reply	[flat|nested] 41+ messages in thread
end of thread, other threads:[~2006-10-03 14:48 UTC | newest]

Thread overview: 41+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2002-11-19  8:07 DNAT problem HCLFM
2002-11-21 21:53 ` Rahul Jadhav
     [not found] <45227670.8040702@mail.nankai.edu.cn>
2006-10-03 14:48 ` Marco Berizzi
     [not found] <4521C6A3.1040902@mail.nankai.edu.cn>
2006-10-03 10:11 ` Marco Berizzi
  -- strict thread matches above, loose matches on Subject: below --
2006-10-02  8:00 Stefan Friedel
2006-10-02  8:25 ` Marco Berizzi
2006-10-02 10:42   ` Pascal Hambourg
2006-10-02 12:01     ` Stefan Friedel
2006-10-02 12:51       ` Marco Berizzi
2006-10-02 13:14       ` Pascal Hambourg
2006-10-02 14:18         ` Stefan Friedel
2006-10-02 12:48     ` Marco Berizzi
2006-07-08 21:00 Antonio Di Bacco
2005-01-22 15:59 dnat problem Pablo Allietti
2005-01-22 19:45 ` Jason Opperisano
2005-01-23  0:26   ` Pablo Allietti
     [not found]     ` <20050125150114.GA25839@omega.lacnic.net.uy>
2005-01-25 15:24       ` Pablo Allietti
2005-01-25 15:25         ` Pablo Allietti
2004-06-10 11:03 DNAT problem Paul M. Goorskis
2004-05-29 15:25 Patrick Leslie Polzer
2004-05-29 15:36 ` Alexis
2004-05-29 16:03   ` Patrick Leslie Polzer
2004-05-30  1:00     ` Alexis
2004-04-27  5:57 [Fwd: Re: DNAT Problem] test
2004-04-27  7:20 ` DNAT Problem Rob Sterenborg
     [not found]   ` <1081.80.0.0.23.1083127867.squirrel@80.0.0.175>
     [not found]     ` <000901c42cef$68603d40$1202a8c0@admin>
2004-05-04  5:32       ` test
2004-04-19  5:07 test
2004-04-19 13:43 ` Joel Newkirk
2004-04-20  4:31   ` test
2004-04-22 10:40     ` test
2004-04-22 11:07       ` Antony Stone
     [not found]         ` <1589.80.0.0.23.1082637754.squirrel@80.0.0.175>
2004-04-22 12:47           ` Antony Stone
2004-04-22 13:06             ` test
2004-04-22 13:21               ` Antony Stone
2004-04-22 18:18                 ` test
2004-04-22 19:13                   ` Antony Stone
2004-04-23 12:22                     ` test
2003-03-30 14:58 DNAT problem Alexandru Coseru
2003-03-30 15:41 ` Joel Newkirk
2002-11-27 19:28 Geoff Silver
2002-05-21 20:53 dnat problem support
2002-06-13 17:28 ` Antony Stone

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