I have setup my linux fedora server and i want to restrict access to my server.Basically i control using iptables.I'm not sure how to write an iptables rules to control drop all connection to port 8080 and allow only certain ip can access the instance on port 8080 example ip=10.254.14.16,192.168.1.10.
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I've read the instruction about setting up the iptables rules to filter all port except HTTP, SSH, FTP. I require first remove all default iptables rules and set default rules to all chains as DROP:
# Set default-deny policies for all three default chains
$IPTABLES -P INPUT DROP
$IPTABLES -P FORWARD DROP
$IPTABLES -P OUTPUT DROP
Then allow only some ports:
#Accept inbound packets that are part of previously-OK'ed sessions
$IPTABLES -A INPUT -j ACCEPT -m state --state ESTABLISHED,RELATED
# Accept inbound packets which initiate SSH sessions
$IPTABLES -A INPUT -p tcp -j ACCEPT --dport 22 -m state --state NEW
# Accept inbound packets which initiate FTP sessions
$IPTABLES -A INPUT -p tcp -j ACCEPT --dport 21 -m state --state NEW
# Accept inbound packets which initiate HTTP sessions
$IPTABLES -A INPUT -p tcp -j ACCEPT --dport 80 -m state --state NEW
# Log anything not accepted above $IPTABLES -A INPUT -j LOG --log-prefix "Dropped by default:"
But I hired a VPS from other country so the only mean I can manage it is via SSH. If I setup the default rule to DROP first, I afraid that I can no longer connect via SSH to tell iptables allow SSH
So my question is:
- Does the IP tables take effect immediately after I input a rule?
- Is there any mean to run this as a batch job (create a script and run all these rules one time).
- My VPS has a web control panel which have a terminal via web. Is this a native terminal or just a connection via port 80 or 22?
Two days ago we started to receive the following message:
/etc/cron.daily/chkrootkit:
The following suspicious files and directories were found:
/lib/init/rw/.mdadm /lib/init/rw/.ramfs
/lib/init/rw/.mdadm
INFECTED (PORTS: 4369)
You have 2 process hidden for ps command
chkproc: Warning: Possible LKM Trojan installed
And about at the same time (a day before that) we have set up new rules for the queueing disciplines using 'tc' on our Debian lenny box (these rules are for some of the experiments we are carrying out). I have ran the chkrootkit manually and this message (as above) keeps appearing, while the rkhunter tool does not complain about these items. Could there be a connection between setting up the new qdisc's and the chkrootkit "INFECTED" messages?
I am trying to program iptable rules for implementing a 1:1 NAT which does the following:
1. Forward all traffic from all ports on a public ip to a private ip
2. Forward traffic from a range of ports (x-->y) on a public ip, to a private ip
I did some google searches for the same, and came up with the following.
iptables -A FORWARD -t filter -o eth0 -m state
state NEW,ESTABLISHED,RELATED -j ACCEPT
iptables -A FORWARD -t filter -i eth0 -m state
state ESTABLISHED,RELATED -j ACCEPT
Can someone please let me know strong iptables rules? Below entries are in iptables file.Here Y.Y.Y.Y is another branch public IP.This server acts as gateway+squid server.Further it will serve company's intranet page also using httpd.OS is CentOS 5.0.
View 1 Replies View RelatedI am setting my firewall rules using the command iptables.My question is i wanna know what command i can use that list rule 2 and 3 for instance in my table?i want to create rule that: The host is administered using SSH, scp and sftp so allow incoming SSH traffic and securing remote file copying and transferring.
View 2 Replies View RelatedWhen I use system-config-firewall, it asks what interfaces to trust. Where does it store that information for iptables (or whatever uses that info)? How iptables knows at what interfaces to use the rules?There is not that kind of information in /etc/sysconf/iptables and iptables-config.
View 2 Replies View Relatedwhat do the following two commands do? Do they modify the iptables rules in any way?
sudo /sbin/iptables -L -n
sudo /sbin/ip6tables -L -n
I need with some iptables rules. I've done all I can, Googling all over, to cover as many exploits as possible and the following script is what I've come up with. The current set up works and I've checked with NMAP. I just need some sort of confirmation that this is pretty much what I can do.
Code:
LAN="eth0 eth1"
RANGE=10.1.0.0/17
WAN=eth2
# Delete all existing rules
[code]....
Also, if I wanted a broadcast to be relayed to all subnets within a defined range, how would such a iptables rule look like? I need this in order to find a networked Canon MP640 printer.
I put together the following filter set :
Code:
#!/bin/sh
#To understand this script, reference the No Starch Press Linux Firewalls Book.
MODPROBE=/sbin/modprobe
IPT=/sbin/iptables
IPTSV=/sbin/iptables-save
IPT6=/sbin/ip6tables
IPT6SV=/sbin/ip6tables-save
### flush / drop policy sets
echo "[+] Flushing existing rules with DEFAULT of DROP [+]"
echo "[+] IPv4 [+]"
$IPT -F
$IPT -F -t nat
$IPT -X
$IPT -P INPUT DROP
$IPT -P OUTPUT DROP
$IPT -P FORWARD DROP
echo "[+] IPv6 [+]"
$IPT6 -F
$IPT6 -F -t nat
$IPT6 -X
$IPT6 -P INPUT DROP
$IPT6 -P OUTPUT DROP
$IPT6 -P FORWARD DROP .....
###OUTPUT rules: LOG rule
$IPT -A OUTPUT -o ! lo -j LOG --log-prefix "DROPED OUTBOUND" --log-ip-options --log-tcp-options
I wanted to know how to allow certain applications through the outbound tables. For example, I wish to be able to use tools such as nmap,tracepath, and traceroute. However, I am not sure where to look to understand the ports to open. I was starting to think that maybe rather than ports to open it would need to be somehthing like tcp flags that would ned to be allowed. Any way, I have tried google and am still haing problems. I started wanting to use these tools due to getting ready for my network+ and security+ certs.
so the firewall rules I am currently using are displayed below.
Code:
# DROP ALL FORWARDED PACKETS
iptables -P FORWARD DROP # DROP ALL PACKETS
# ALLOW DHCP THROUGH THE FIREWALL
[code]....
I have been trying to figure out how to makes rules in iptables that expire after a certain amount of time. From what I have found online you want to use the recent module with --rcheck and --seconds. I have found a few examples and have given them a shot but I can't seem to get it right. Would anyone mind posting an example of a rule that will auto expire?
View 3 Replies View RelatedI've configured squid proxy server in a P4 desktop. I've 50 users in my network. I installed RHEL 4.4 (2.6.9-42 kernel) and the iptables version is 1.2.11-3.1. I've 2 NICs installed in the system. eth0 (192.168.100.99) for local lan and eth1 (192.168.1.2) for outgoing to internet. I've connected DSL broadband modem to eth1 (default ip of DSL modem is 192.168.1.1). All the clients except few has been forced to go through squid by user authentication to access internet. Those clients which were kept away from proxy are 192.168.100.253, 192.168.100.97, 192.168.100.95 and 192.168.100.165. Everything works fine but from last week I observed that one of some notorious user use the direct IPs (192.168.100.97 or 192.168.100.95) in the absense of the owner of these IPs to gain access to internet as we applied download/upload restrictions in squid.
I want to filter the packets of source hosts using MAC address in PREROUTING chain. I read somewhere that IPT_MAC module must be installed to make this happen. So that those notorious users can not change their ips to gain direct access to internet.
Below are the contents of my iptables file (I've ommited few entries for safty purpose).
# Generated by iptables-save v1.2.11 on Wed Nov 25 16:35:57 2009
*filter
:INPUT ACCEPT [14274:3846787]
:FORWARD ACCEPT [4460:1241297]
:OUTPUT ACCEPT [16825:4872475]
code....
I was wondering if there is a way to find out IP blocks based on a given region. I know there are IP Lookups that will tell you what Country and possibly City a given IP is from. What I want is the following:
- I would like to set up a IPTABLES rule that implements something like:
=> ALLOW VPN connections FROM THIS ISP/IP BLOCKS THAT ARE IN CITY XYZ
Basically, I want to limit my incoming VPN connections FROM my ISP in the surrounding area. So, for example, I can go to my friends house who also has the same ISP. I should be able to connect from his home to mine because we have 1) same ISP 2) IP blocks is confined to a particular local location.
I two servers set up: 192.168.1.150 and 192.168.1.160 Initially, I want all traffic to be served by server 150. So for this purpose I am leaving the IPTables on .150 empty. At a point in time, I want to forward all incoming traffic to be served by .160 instead. I have accomplished this using these commands (on .150):
iptables -t nat -A PREROUTING -j DNAT --to 192.168.1.160
iptables -t nat -I POSTROUTING -j MASQUERADE
My problem is that if I have an open SSH connection to .150 (prior to adding the rules), the packets are still handled by .150 after adding the rules.. e.g. my SSH session stays active. I want these packets to be forwarded to .160, which would effectively disconnect the SSH session. I do not want the packets flat out dropped, I just want them forwarded on in whatever state they are in. If I try a new SSH session, it is properly forwarded to .160
I'm trying to configure Iptables and I just want to block everything but http/https. However, my connection is pppoe, so I have the ppp0 interface. Pretty much every Iptables tutorial that I found don't teach how to deal with this kind of setup. I'm forwarding the ppp0 to eth0 and I could configure the input rules and they're working. After this, I need to configure the output but nothing seems to work.
The current working rules are:
Code:
Chain INPUT (policy ACCEPT 7858 packets, 5792K bytes)
pkts bytes target prot opt in out source destination
299 201K ACCEPT all -- any any anywhere anywhere state RELATED,ESTABLISHED
0 0 ACCEPT tcp -- any any anywhere anywhere tcp dpt:www
0 0 ACCEPT tcp -- any any anywhere anywhere tcp dpt:https
11 820 DROP all -- any any anywhere anywhere
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 ACCEPT all -- eth0 ppp0 anywhere anywhere
0 0 ACCEPT all -- ppp0 eth0 anywhere anywhere state RELATED,ESTABLISHED
Chain OUTPUT (policy ACCEPT 10791 packets, 1951K bytes)
pkts bytes target prot opt in out source destination
I don't understand what those "state RELATED,ESTABLISHED" rules do. Also, I don't know if this rules are secure, because i'm very confused about the ppp0/eth0 interfaces.
How can I drop or forward a incoming connection from a part of a host like *.alicedsl.de
For example:
The user is connection from *.alicedsl.de on port 12345
So how can I drop this connection or forward to google.com on port 80
I'm trying to use these cookie cutter rules that I found. But every time I use them, after a few seconds my wifi connection goes dead. The exception was the first time I used then. Which lasted me a couple of minutes.
By dead I mean I can no longer open a webpage or ping google.
iptables -N LOGGING
iptables -A INPUT -j LOGGING
iptables -A OUTPUT -j LOGGING
iptables -A LOGGING -m limit --limit 2/min -j LOG --log-prefix "IPTables-Dropped: " --log-level 4
iptables -A LOGGING -j DROP
I'm trying to automatically load some iptables rules by adding the below script in the /etc/network/if-up.d directory:
Code:
#!/bin/sh
IPTABLES=/sbin/iptables[code]...............
how can i drop igmp port 0 packets with iptables rule? my log file is full of this router advertisement.
View 2 Replies View RelatedI am setting up tomcat server on my Centos 5.5 machine. I've been advised to run tomcat on 8080 as non root user and redirect traffic to it from port 80.
I searched and found the following iptables commands for this:# iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT -to-ports 8080
# iptables -I INPUT -p tcp --dport 8080 -j ACCEPTI have a doubt:
Tomcat is not accessible via port 80 without the second command. But the second command opens 8080 and makes it accessible over the internet (tomcat is accesible via both: www.<website>.com and http://<ip address>:8080). This doesn't seem right. Is there some simple (iptables) way to redirect traffic "internally" from port 80 to 8080 without having to open 8080 to the internet.
I want to simplify some of my rules, so I want to create rules for certain services like xmpp, web, etc. since some of them use multiple ports, and I toggle them on/off a lot. Can I simply put the jump to rule clauses in the Input chain, and once the sub chains run, does it return to the input chain after the jump to rule clause? I want to do this so I don't have a ton of rules in the input chain. I think that if I simply make a list of all the rules to jump to in the input chain, it will work itself through all of them until it finds a matching filter in one of them correct?
View 9 Replies View RelatedIPtables creates an error during startup as well as when I try to restart it: Here's the output of:
[Code]....
I am running Ubuntu server 10.10 and trying to setup iptables rules in /etc/if-up.d/iptables
Quote:
root@host# cat /etc/network/if-up.d/iptables
#!/bin/sh -e
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
Problem is that iptables doesn't get updated and I don't see them when iptables -L is executed after reboot.
I am wondering if it's possible to log the number of bytes a connection transfered when the connection is complete with iptables. I know I've seen this sort of information in Cisco FWSM logs, where the "Teardown" entry of the logs has the bytes transferred for that connection. Is it possible to have something similar to that with iptables? Where the initial connection attempt is logged (i.e. NEW, which I have logging fine) AND an entry for that connection that includes the bytes transferred?
View 6 Replies View RelatedI have several CS servers running on ubuntu server, and sometimes someone is trying to brute server's RCON password with the program called HLBrute. I've found the following rules to prevent such hack attacks, but they don't work What can be wrong in these rules?
Quote:
iptables -A INPUT -p udp -m multiport --dport 26000:30000 -m string --algo kmp --string "HLBrute" -m limit --limit 1/hour --limit-burst 5 -j LOG --log-prefix " HLBrute_Ataka "
iptables -A INPUT -p udp -m multiport --dport 26000:30000 -m string --algo kmp --string "HLBrute" -j DROP
I am at a loss how to prevent Denial of Service attacks to port 25 and not block legitimate connections from 2 Barracuda 800(s) and block smart phones such as iPhones/Blackberrys/iPhones that use the server smtp.server.com for email.
Presently for port 25
RH-Firewall-1-INPUT -p tcp -m state --state NEW -m tcp --dport 25 -j ACCEPT
The 2 Barracuda 800(s) make port 25 connections all the time, plus users with smart_phones have the incoming server type:
IMAP
pop.server.com
smtp.server.com
Is there a way to keep Denial of Service attacks from happening with iptables rules without causing blocking to the Barracuda(s) that make constant port 25 connections & smart phones that poll? I was thinking if I allowed the Barracuda(s) in these lines
-s (barracuda)24.xx.xx.xx -d (emailserver)24.00.xx.xx -p tcp -m tcp --dport 25 -m state --state NEW -j ACCEPT
Where the source would be the Barracuda going to the email server. It would be allowed, then I am left with how to allow other connections like Smart_Phones that connect via Port 25. I am thinking if I put rules in place doing connection counts in a minute it would result in errors connecting to the server and people would start complaining. Plus any limiting may result in blocking real traffic. Then would I need to allow the ISP range in the above example to accept port 25, I am still left with how to drop a flood/denial of service attack.
I added a few rules to my /etc/iptables.rules file and then used sudo iptables-restore < /etc/iptables.rules but i got an error saying "iptables-restore: line 29 failed".But the only word on that line.
View 1 Replies View RelatedI followed one of these tutos [URL]. My OS is Debian Lennny, iptables v1.4.2.
My iptables -L
iptables -L
Chain INPUT (policy ACCEPT)
target prot opt source destination
ACCEPT all -- anywhere anywhere
ACCEPT all -- anywhere anywhere state RELATED, ESTABLISHED
ACCEPT tcp -- anywhere anywhere tcp dpt:xxxx
ACCEPT icmp -- proxy.provider.net anywhere
ACCEPT icmp -- proxy.p19.provider.net anywhere
ACCEPT icmp -- proxy.rbx.provider.net anywhere
ACCEPT icmp -- proxy.rbx2.provider.net anywhere
ACCEPT icmp -- ping.provider.net anywhere
ACCEPT tcp -- cache.provider.net anywhere tcp dpt:ssh
DROP all -- anywhere anywhere
Chain FORWARD (policy ACCEPT)
target prot opt source destination
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
ACCEPT all -- anywhere anywhere
ACCEPT udp -- anywhere anywhere udp dpt:domain
ACCEPT tcp -- anywhere anywhere tcp dpt:domain
ACCEPT tcp -- anywhere anywhere multiport dports www,https
ACCEPT icmp -- anywhere anywhere icmp echo-request
ACCEPT tcp -- anywhere anywhere tcp dpt:ssh
ACCEPT tcp -- anywhere anywhere tcp dpt:xxxx
As soon as I add "iptables -A OUTPUT -j DROP" server lock me out and I have to reboot to be able log back. The ssh port is open in both INPUT and OUTPUT what's wrong?
I have tried to google it around and couldn't find any good solution for it. What I want is to hook up to the kernel network hooks and for example investigate all of the packets (maybe keep some in the buffer and drop in the kernel so I could send them out lets say 10 minutes later) but from a C / C++ program perspective / level. I know it can be done via iptables but isn't there a way to do it from a program ?? I have found a library called ipq but apparently doesn't work with kernel 2.6.x anymore.
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