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iptables : masq

DISCUSSION Sathi 5 participants 6 messages Jun 13, 2002 – Jun 14, 2002 1 message not in the archive

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Sathi

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#1 lore raw

Use
#iptables -t nat -L

-Sathayn

----- Original Message -----
From: Payal <[email protected]>
To: <[email protected]>
Sent: Thursday, June 13, 2002 3:28 PM
Subject: iptables : masq

Hi,
As I said earlier I am using Mdk Linux 8.2 with kernel 2.4.18. I am trying to
shift from ipchains to iptables for a simple reson that I cannot connect to one particular ftp site where ip_masq_ftp was required in earlier versions of
kernel. Now this module is no longer available. So, I have to shift to iptables since connecting to that site is really imp.
But I am having a problem. I read briefly NAT and iptables HOWTOs and decided
the rule,
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

My loaded modules by lsmod include,

ipt_MASQUERADE          1504   5  (autoclean)
iptable_mangle          2336   0  (autoclean) (unused)
iptable_nat            15988   1  (autoclean) [ipt_MASQUERADE]
ip_conntrack           15180   1  (autoclean) [ipt_MASQUERADE iptable_nat]
iptable_filter          1952   0  (autoclean)
ip_tables              11584   6  [ipt_MASQUERADE iptable_mangle iptable_nat

iptable_filter]

But my problem is that inspite of giving the above command I have,

#iptables --list
Chain INPUT (policy ACCEPT)
target prot opt source destination

Chain FORWARD (policy ACCEPT)
target prot opt source destination

Chain OUTPUT (policy ACCEPT)
target prot opt source destination

What is wrong now? Why is'nt my rule listed?
I even have 1 in /proc/sys/net/ipv4/ip_forward.
Please do tell as early as possible or atleast tell me how to get it working under ipchains.

Thanks a lot in advance and bye.
-Payal
p.s i have some problems with my present email address, it would be great if you can cc the mail to payal99 @ cyberspace.org

#2 lore raw

Hi,
Thanks for the mail.
I could see the rules properly now.
[root]# iptables -t nat -L
Chain PREROUTING (policy ACCEPT)
target prot opt source destination

Chain POSTROUTING (policy ACCEPT)
target prot opt source destination
MASQUERADE all -- anywhere anywhere

Chain OUTPUT (policy ACCEPT)
target prot opt source destination

But now the problem is that if I try to ping a site or external ip from a computer from internal network I still don't get the site. The command I used was,
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
Thanks a lot again and waiting for the replies.

[email protected]

Quoted 51 lines

Use
#iptables -t nat -L

-Sathayn

----- Original Message -----
From: Payal <[email protected]>
To: <[email protected]>
Sent: Thursday, June 13, 2002 3:28 PM
Subject: iptables : masq

Hi,
As I said earlier I am using Mdk Linux 8.2 with kernel 2.4.18. I am trying to
shift from ipchains to iptables for a simple reson that I cannot connect to one particular ftp site where ip_masq_ftp was required in earlier versions of
kernel. Now this module is no longer available. So, I have to shift to iptables since connecting to that site is really imp.
But I am having a problem. I read briefly NAT and iptables HOWTOs and decided
the rule,
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

My loaded modules by lsmod include,

ipt_MASQUERADE          1504   5  (autoclean)
iptable_mangle          2336   0  (autoclean) (unused)
iptable_nat            15988   1  (autoclean) [ipt_MASQUERADE]
ip_conntrack           15180   1  (autoclean) [ipt_MASQUERADE iptable_nat]
iptable_filter          1952   0  (autoclean)
ip_tables              11584   6  [ipt_MASQUERADE iptable_mangle iptable_nat

iptable_filter]

But my problem is that inspite of giving the above command I have,

#iptables --list
Chain INPUT (policy ACCEPT)
target prot opt source destination

Chain FORWARD (policy ACCEPT)
target prot opt source destination

Chain OUTPUT (policy ACCEPT)
target prot opt source destination

What is wrong now? Why is'nt my rule listed?
I even have 1 in /proc/sys/net/ipv4/ip_forward.
Please do tell as early as possible or atleast tell me how to get it working under ipchains.

Quoted 7 lines

Thanks a lot in advance and bye.
-Payal
p.s i have some problems with my present email address, it would be great if you can cc the mail to payal99 @ cyberspace.org

---------------------------------------------
http://mail.indiainfo.com
India's first ISO certified portal
Check world time at http://time.indiainfo.com

#3 lore raw
In reply to a message not in the archive

Hi

Quoted 11 lines · Payal

Hi,
As I said earlier I am using Mdk Linux 8.2 with kernel 2.4.18. I am trying to shift from ipchains to iptables for a simple reson that I cannot connect to one particular ftp site where ip_masq_ftp was required in earlier versions of kernel. Now this module is no longer available. So, I have to shift to iptables since connecting to that site is really imp.
But I am having a problem. I read briefly NAT and iptables HOWTOs and decided the rule,
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

Quoted 8 lines

My loaded modules by lsmod include,

ipt_MASQUERADE          1504   5  (autoclean)
iptable_mangle          2336   0  (autoclean) (unused)
iptable_nat            15988   1  (autoclean) [ipt_MASQUERADE]
ip_conntrack           15180   1  (autoclean) [ipt_MASQUERADE

iptable_nat] iptable_filter 1952 0 (autoclean)
ip_tables 11584 6 [ipt_MASQUERADE iptable_mangle
iptable_nat iptable_filter]

You will also need the modules ip_conntrack_ftp.o ip_nat_ftp.o. Otherwise you will not succeed in doing active FTP.

greetings
Axel

#4 lore raw

Is that correct ?

Am I not the only one who thinks the instructions for NATing FTP are V.contradictory ?

ps. This is NOT a flame I think IPTABLES is excellent...

My firewall did have :
modprobe ip_conntrack
modprobe ip_conntrack_ftp

This worked for some FTP connections but not for others..

I've now added :
modprobe ip_nat_ftp
to see if that helps.

Is their some clear documentation on FTP NAT somewhere ?

Quoted 33 lines · Axel Heinrici

Hi

Quoted 11 lines · Payal

Hi,
As I said earlier I am using Mdk Linux 8.2 with kernel 2.4.18. I am trying to shift from ipchains to iptables for a simple reson that I cannot connect to one particular ftp site where ip_masq_ftp was required in earlier versions of kernel. Now this module is no longer available. So, I have to shift to iptables since connecting to that site is really imp.
But I am having a problem. I read briefly NAT and iptables HOWTOs and decided the rule,
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

Quoted 10 lines

My loaded modules by lsmod include,

ipt_MASQUERADE          1504   5  (autoclean)
iptable_mangle          2336   0  (autoclean) (unused)
iptable_nat            15988   1  (autoclean) [ipt_MASQUERADE]
ip_conntrack           15180   1  (autoclean) [ipt_MASQUERADE

iptable_nat] iptable_filter 1952 0 (autoclean)
ip_tables 11584 6 [ipt_MASQUERADE iptable_mangle
iptable_nat iptable_filter]

You will also need the modules ip_conntrack_ftp.o ip_nat_ftp.o. Otherwise you will not succeed in doing active FTP.

greetings
Axel

Signature · 11 lines
Regards,

Malcolm Turnbull

IT Manager
Crocus.co.uk Ltd

01344 629661
07715 770523

http://www.crocus.co.uk/
#5 lore raw
In reply to Axel Heinrici

Hi,
Thanks a lot for the replies. I got it solved thankkkkkkkkkkks a lot to all of you.
Byeeeee.
-Payal

Quoted 28 lines · you

Hi

Quoted 11 lines · Payal

Hi,
As I said earlier I am using Mdk Linux 8.2 with kernel 2.4.18. I am trying to shift from ipchains to iptables for a simple reson that I cannot connect to one particular ftp site where ip_masq_ftp was required in earlier versions of kernel. Now this module is no longer available. So, I have to shift to iptables since connecting to that site is really imp.
But I am having a problem. I read briefly NAT and iptables HOWTOs and decided the rule,
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

Quoted 8 lines

My loaded modules by lsmod include,

ipt_MASQUERADE          1504   5  (autoclean)
iptable_mangle          2336   0  (autoclean) (unused)
iptable_nat            15988   1  (autoclean) [ipt_MASQUERADE]
ip_conntrack           15180   1  (autoclean) [ipt_MASQUERADE

iptable_nat] iptable_filter 1952 0 (autoclean)
ip_tables 11584 6 [ipt_MASQUERADE iptable_mangle
iptable_nat iptable_filter]

You will also need the modules ip_conntrack_ftp.o ip_nat_ftp.o. Otherwise you will not succeed in doing active FTP.

greetings
Axel

#6 lore raw
In reply to Axel Heinrici

Hi,
Thanks a lot for the replies. I got it solved thankkkkkkkkkkks a lot to all of you.
Byeeeee.
-Payal

Quoted 28 lines · you

Hi

Quoted 11 lines · Payal

Hi,
As I said earlier I am using Mdk Linux 8.2 with kernel 2.4.18. I am trying to shift from ipchains to iptables for a simple reson that I cannot connect to one particular ftp site where ip_masq_ftp was required in earlier versions of kernel. Now this module is no longer available. So, I have to shift to iptables since connecting to that site is really imp.
But I am having a problem. I read briefly NAT and iptables HOWTOs and decided the rule,
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

Quoted 8 lines

My loaded modules by lsmod include,

ipt_MASQUERADE          1504   5  (autoclean)
iptable_mangle          2336   0  (autoclean) (unused)
iptable_nat            15988   1  (autoclean) [ipt_MASQUERADE]
ip_conntrack           15180   1  (autoclean) [ipt_MASQUERADE

iptable_nat] iptable_filter 1952 0 (autoclean)
ip_tables 11584 6 [ipt_MASQUERADE iptable_mangle
iptable_nat iptable_filter]

You will also need the modules ip_conntrack_ftp.o ip_nat_ftp.o. Otherwise you will not succeed in doing active FTP.

greetings
Axel