Today (Saturday) We will make some minor tuning adjustments to MySQL.

You may experience 2 up to 10 seconds "glitch time" when we restart MySQL. We expect to make these adjustments around 1AM Eastern Daylight Saving Time (EDT) US.


iptables as "proxy" and a filter

Login or Register for Dates, Times and to Reply

 
Thread Tools Search this Thread
# 1  
iptables as "proxy" and a filter

Dear community,
since I am a german guy, excuse gramatical mistakes.

I create a proxy to hide my application servers public IP from my customers.
I am actually using those 3 lines
(for testing reasons I am forwarding the traffic which connects to the ubuntu proxy to my apache webserver (5.196.130.245:80)

Code:
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A PREROUTING -p tcp --dport 80 -j DNAT --to-destination 5.196.130.245:80
iptables -t nat -A POSTROUTING -j MASQUERADE

I show this to a friend/competitor and he said, lol, with this code ur "hiding" the costumers IP in ur Database logs
(for example, they use the register formular on the website username, password registerIP - and with my 3 lines of code the register IP is the proxys IP in every single case but he told me he got a way to see even the real Users IP, even if they connecting through the proxy)

So he sent me the following Picture of his script
Image

Any1 knows / is able to describe me what he has done better / other than me? I cannot see any routing cmds in his script.

I'm now almost searching 5 days for a solution and this is my last hope to find it.


EDIT: okay, I just found out that this Script for setting up the iptables is not for forwarding any traffic.
For the redirecting/forwarding part he is using HAPROXY.

regards,
Julian

Last edited by tschulian; 11-25-2014 at 04:13 PM.. Reason: code tags not icode ... thanks
# 2  
One thing I note in your friend's script is that it sets the firewall to drop all incoming connections before allowing port 22 (ssh) connections. If something goes wrong along the way on this, you'll need console access to get back in :/ I'd recommend setting the -P INPUT DROP last tbh Smilie

As you've noted, this is just INPUT filters, your one is just NAT/IPMASQ. So it's like comparing apples and oranges really.

Looking just at your rules, I don't see anything untoward there, it appears that you are causing the proxy to accept traffic arriving on port 80 and redirecting it to 5.196.130.245.

An external customer connecting to the address would not be able to detect the redirect and would see all their connections as going to and coming back from the address of your proxy.
The webserver would see all the connections as coming from the proxy server address, unless the customer is setting "X-Forwarded-For" headers in their requests (not all that uncommon to find) which would be passed along to the webserver and quite possibly included in it's logs.

If you have a little more background of what your end goal is, we might be able to offer more advice Smilie

I would recommend also adding a FORWARD rule to DROP anything not for that port arriving from the external interface, as you've turned on IP forwarding and at present your setup would happily forward anything anyone asks it to. It's note really serious but could exacerbate any existing security issue into a full exploit.
Login or Register for Dates, Times and to Reply

Previous Thread | Next Thread
Thread Tools Search this Thread
Search this Thread:
Advanced Search

9 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Bash script - Print an ascii file using specific font "Latin Modern Mono 12" "regular" "9"

Hello. System : opensuse leap 42.3 I have a bash script that build a text file. I would like the last command doing : print_cmd -o page-left=43 -o page-right=22 -o page-top=28 -o page-bottom=43 -o font=LatinModernMono12:regular:9 some_file.txt where : print_cmd ::= some printing... (1 Reply)
Discussion started by: jcdole
1 Replies

2. UNIX for Dummies Questions & Answers

Grep : Filter/Move All The Lines Containing Not More Than One "X" Character Into A Text File

Hi All It's me again with another huge txt files. :confused: What I have: - I have 33 huge txt files in a folder. - I have thousands of line in this txt file which contain many the letter "x" in them. - Some of them have more than one "x" character in the line. What I want to achieve:... (8 Replies)
Discussion started by: Nexeu
8 Replies

3. UNIX for Dummies Questions & Answers

Using "mailx" command to read "to" and "cc" email addreses from input file

How to use "mailx" command to do e-mail reading the input file containing email address, where column 1 has name and column 2 containing “To” e-mail address and column 3 contains “cc” e-mail address to include with same email. Sample input file, email.txt Below is an sample code where... (2 Replies)
Discussion started by: asjaiswal
2 Replies

4. Shell Programming and Scripting

Filter file by length, looking only at lines that don't begin with ">"

I have a file that stores data in pairs of lines, following this format: line 1: header (preceded by ">") line 2: sequence Example.txt: >seq1 name GATTGATGTTTGAGTTTTGGTTTTT >seq2 name TTTTCTTC I want to filter out the sequences and corresponding headers for all sequences that are less... (2 Replies)
Discussion started by: pathunkathunk
2 Replies

5. Solaris

The slices "usr", "opt", "tmp" disappeared!!! Help please.

The system don't boot. on the screen appears following: press enter to maintenance (or type CTRL-D to continue)...I checked with format command. ... the slices "0-root","1-swap","2-backup" exist. ...the slises "3-var","6-usr" -unassigned. :( (16 Replies)
Discussion started by: wolfgang
16 Replies

6. Shell Programming and Scripting

how to use "cut" or "awk" or "sed" to remove a string

logs: "/home/abc/public_html/index.php" "/home/abc/public_html/index.php" "/home/xyz/public_html/index.php" "/home/xyz/public_html/index.php" "/home/xyz/public_html/index.php" how to use "cut" or "awk" or "sed" to get the following result: abc abc xyz xyz xyz (8 Replies)
Discussion started by: timmywong
8 Replies

7. Shell Programming and Scripting

awk command to replace ";" with "|" and ""|" at diferent places in line of file

Hi, I have line in input file as below: 3G_CENTRAL;INDONESIA_(M)_TELKOMSEL;SPECIAL_WORLD_GRP_7_FA_2_TELKOMSEL My expected output for line in the file must be : "1-Radon1-cMOC_deg"|"LDIndex"|"3G_CENTRAL|INDONESIA_(M)_TELKOMSEL"|LAST|"SPECIAL_WORLD_GRP_7_FA_2_TELKOMSEL" Can someone... (7 Replies)
Discussion started by: shis100
7 Replies

8. Shell Programming and Scripting

cat $como_file | awk /^~/'{print $1","$2","$3","$4}' | sed -e 's/~//g'

hi All, cat file_name | awk /^~/'{print $1","$2","$3","$4}' | sed -e 's/~//g' Can this be done by using sed or awk alone (4 Replies)
Discussion started by: harshakusam
4 Replies

9. UNIX for Dummies Questions & Answers

Explain the line "mn_code=`env|grep "..mn"|awk -F"=" '{print $2}'`"

Hi Friends, Can any of you explain me about the below line of code? mn_code=`env|grep "..mn"|awk -F"=" '{print $2}'` Im not able to understand, what exactly it is doing :confused: Any help would be useful for me. Lokesha (4 Replies)
Discussion started by: Lokesha
4 Replies

Featured Tech Videos