IP tables-the linux firewall. This link shows the pdf document that you can download.This is a useful document for the beginners, lays the attention to know more about the topic.
In the following slides we will show you how to create a #DMZ using the #FortiGate
#Firewall. See next chapters on #FortiGate configuration. Stay with us!
Computers are connected in a network to exchange information or resources with each other. Two or more computer are connected through network media called computer media.
There are a number of network devices or media that are involved to form computer network.
Computer loaded with Linux Operation System can also be a part of network whether it is a small or large network by multitasking and multi user natures.
Maintaining of system and network up and running is a task of System / Network Administrator’s job. In this article we are going to review frequently used network configuration and troubleshoot commands in Linux.
In this PPT you can learn a firewall and types which help you a lot and you can able to understand. So, that you must read at once I sure that you are understand
Thank you!!!
I
IPS (Intrusion Prevention System) is definitely the next level of security technology with its capability to
provide security at all system levels from the operating system kernel to network data packets. It
provides policies and rules for network traffic along with an IDS for alerting system or network
administrators to suspicious traffic, but allows the administrator to provide the action upon being
alerted. Where IDS informs of a potential attack, an IPS makes attempts to stop it. Another huge leap
over IDS, is that IPS has the capability of being able to prevent known intrusion signatures, but also
some unknown attacks due to its database of generic attack behaviours. Thought of as a combination of
IDS and an application layer firewall for protection, IPS is generally considered to be the "next
generation" of IDS.
In the following slides we will show you how to create a #DMZ using the #FortiGate
#Firewall. See next chapters on #FortiGate configuration. Stay with us!
Computers are connected in a network to exchange information or resources with each other. Two or more computer are connected through network media called computer media.
There are a number of network devices or media that are involved to form computer network.
Computer loaded with Linux Operation System can also be a part of network whether it is a small or large network by multitasking and multi user natures.
Maintaining of system and network up and running is a task of System / Network Administrator’s job. In this article we are going to review frequently used network configuration and troubleshoot commands in Linux.
In this PPT you can learn a firewall and types which help you a lot and you can able to understand. So, that you must read at once I sure that you are understand
Thank you!!!
I
IPS (Intrusion Prevention System) is definitely the next level of security technology with its capability to
provide security at all system levels from the operating system kernel to network data packets. It
provides policies and rules for network traffic along with an IDS for alerting system or network
administrators to suspicious traffic, but allows the administrator to provide the action upon being
alerted. Where IDS informs of a potential attack, an IPS makes attempts to stop it. Another huge leap
over IDS, is that IPS has the capability of being able to prevent known intrusion signatures, but also
some unknown attacks due to its database of generic attack behaviours. Thought of as a combination of
IDS and an application layer firewall for protection, IPS is generally considered to be the "next
generation" of IDS.
iptables is a user-space utility program that allows a system administrator to configure the tables provided by the Linux kernel firewall (implemented as different Netfilter modules) and the chains and rules it store
The Next Generation Firewall for Red Hat Enterprise Linux 7 RCThomas Graf
The Linux packet filtering technology, iptables, has its roots in times when networking was relatively simple and network bandwidth was measured in mere megabits. Emerging technologies, such as distributed NAT, overlay networks and containers require enhanced functionality and additional flexibility. In parallel, the next generation of network cards with speeds of 40Gb and 100Gb will put additional pressure on performance.
In the upcoming Red Hat Enterprise Linux 7, a new dynamic firewall service, FirewallD, is planned to provide greater flexibility over iptables by eliminating service disruptions during rule updates, abstraction, and support for different network trust zones. Additionally, a new virtual machine-based packet filtering technology, nftables, addresses the functionality and flexibility requirements of modern network workloads.
In this session you’ll:
Deep dive into the newly introduced packet filtering capabilities of Red Hat Enterprise Linux 7 beta.
Learn best practices.
See the new set of configuration utilities that allow new optimization possibilities.
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
Connector Corner: Automate dynamic content and events by pushing a buttonDianaGray10
Here is something new! In our next Connector Corner webinar, we will demonstrate how you can use a single workflow to:
Create a campaign using Mailchimp with merge tags/fields
Send an interactive Slack channel message (using buttons)
Have the message received by managers and peers along with a test email for review
But there’s more:
In a second workflow supporting the same use case, you’ll see:
Your campaign sent to target colleagues for approval
If the “Approve” button is clicked, a Jira/Zendesk ticket is created for the marketing design team
But—if the “Reject” button is pushed, colleagues will be alerted via Slack message
Join us to learn more about this new, human-in-the-loop capability, brought to you by Integration Service connectors.
And...
Speakers:
Akshay Agnihotri, Product Manager
Charlie Greenberg, Host
DevOps and Testing slides at DASA ConnectKari Kakkonen
My and Rik Marselis slides at 30.5.2024 DASA Connect conference. We discuss about what is testing, then what is agile testing and finally what is Testing in DevOps. Finally we had lovely workshop with the participants trying to find out different ways to think about quality and testing in different parts of the DevOps infinity loop.
JMeter webinar - integration with InfluxDB and GrafanaRTTS
Watch this recorded webinar about real-time monitoring of application performance. See how to integrate Apache JMeter, the open-source leader in performance testing, with InfluxDB, the open-source time-series database, and Grafana, the open-source analytics and visualization application.
In this webinar, we will review the benefits of leveraging InfluxDB and Grafana when executing load tests and demonstrate how these tools are used to visualize performance metrics.
Length: 30 minutes
Session Overview
-------------------------------------------
During this webinar, we will cover the following topics while demonstrating the integrations of JMeter, InfluxDB and Grafana:
- What out-of-the-box solutions are available for real-time monitoring JMeter tests?
- What are the benefits of integrating InfluxDB and Grafana into the load testing stack?
- Which features are provided by Grafana?
- Demonstration of InfluxDB and Grafana using a practice web application
To view the webinar recording, go to:
https://www.rttsweb.com/jmeter-integration-webinar
Search and Society: Reimagining Information Access for Radical FuturesBhaskar Mitra
The field of Information retrieval (IR) is currently undergoing a transformative shift, at least partly due to the emerging applications of generative AI to information access. In this talk, we will deliberate on the sociotechnical implications of generative AI for information access. We will argue that there is both a critical necessity and an exciting opportunity for the IR community to re-center our research agendas on societal needs while dismantling the artificial separation between the work on fairness, accountability, transparency, and ethics in IR and the rest of IR research. Instead of adopting a reactionary strategy of trying to mitigate potential social harms from emerging technologies, the community should aim to proactively set the research agenda for the kinds of systems we should build inspired by diverse explicitly stated sociotechnical imaginaries. The sociotechnical imaginaries that underpin the design and development of information access technologies needs to be explicitly articulated, and we need to develop theories of change in context of these diverse perspectives. Our guiding future imaginaries must be informed by other academic fields, such as democratic theory and critical theory, and should be co-developed with social science scholars, legal scholars, civil rights and social justice activists, and artists, among others.
The Art of the Pitch: WordPress Relationships and SalesLaura Byrne
Clients don’t know what they don’t know. What web solutions are right for them? How does WordPress come into the picture? How do you make sure you understand scope and timeline? What do you do if sometime changes?
All these questions and more will be explored as we talk about matching clients’ needs with what your agency offers without pulling teeth or pulling your hair out. Practical tips, and strategies for successful relationship building that leads to closing the deal.
PHP Frameworks: I want to break free (IPC Berlin 2024)Ralf Eggert
In this presentation, we examine the challenges and limitations of relying too heavily on PHP frameworks in web development. We discuss the history of PHP and its frameworks to understand how this dependence has evolved. The focus will be on providing concrete tips and strategies to reduce reliance on these frameworks, based on real-world examples and practical considerations. The goal is to equip developers with the skills and knowledge to create more flexible and future-proof web applications. We'll explore the importance of maintaining autonomy in a rapidly changing tech landscape and how to make informed decisions in PHP development.
This talk is aimed at encouraging a more independent approach to using PHP frameworks, moving towards a more flexible and future-proof approach to PHP development.
Transcript: Selling digital books in 2024: Insights from industry leaders - T...BookNet Canada
The publishing industry has been selling digital audiobooks and ebooks for over a decade and has found its groove. What’s changed? What has stayed the same? Where do we go from here? Join a group of leading sales peers from across the industry for a conversation about the lessons learned since the popularization of digital books, best practices, digital book supply chain management, and more.
Link to video recording: https://bnctechforum.ca/sessions/selling-digital-books-in-2024-insights-from-industry-leaders/
Presented by BookNet Canada on May 28, 2024, with support from the Department of Canadian Heritage.
Neuro-symbolic is not enough, we need neuro-*semantic*Frank van Harmelen
Neuro-symbolic (NeSy) AI is on the rise. However, simply machine learning on just any symbolic structure is not sufficient to really harvest the gains of NeSy. These will only be gained when the symbolic structures have an actual semantics. I give an operational definition of semantics as “predictable inference”.
All of this illustrated with link prediction over knowledge graphs, but the argument is general.
UiPath Test Automation using UiPath Test Suite series, part 4DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 4. In this session, we will cover Test Manager overview along with SAP heatmap.
The UiPath Test Manager overview with SAP heatmap webinar offers a concise yet comprehensive exploration of the role of a Test Manager within SAP environments, coupled with the utilization of heatmaps for effective testing strategies.
Participants will gain insights into the responsibilities, challenges, and best practices associated with test management in SAP projects. Additionally, the webinar delves into the significance of heatmaps as a visual aid for identifying testing priorities, areas of risk, and resource allocation within SAP landscapes. Through this session, attendees can expect to enhance their understanding of test management principles while learning practical approaches to optimize testing processes in SAP environments using heatmap visualization techniques
What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
Topics covered:
Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Dev Dives: Train smarter, not harder – active learning and UiPath LLMs for do...UiPathCommunity
💥 Speed, accuracy, and scaling – discover the superpowers of GenAI in action with UiPath Document Understanding and Communications Mining™:
See how to accelerate model training and optimize model performance with active learning
Learn about the latest enhancements to out-of-the-box document processing – with little to no training required
Get an exclusive demo of the new family of UiPath LLMs – GenAI models specialized for processing different types of documents and messages
This is a hands-on session specifically designed for automation developers and AI enthusiasts seeking to enhance their knowledge in leveraging the latest intelligent document processing capabilities offered by UiPath.
Speakers:
👨🏫 Andras Palfi, Senior Product Manager, UiPath
👩🏫 Lenka Dulovicova, Product Program Manager, UiPath
2. IntroductionIntroduction
●
Network security is a primary consideration in any decision to host aNetwork security is a primary consideration in any decision to host a
website as the threats are becoming more widespread and persistentwebsite as the threats are becoming more widespread and persistent
every day.every day.
●
We can convert a Linux server into:We can convert a Linux server into:
A firewall while simultaneously being our home website's mail,A firewall while simultaneously being our home website's mail,
web and DNS server.web and DNS server.
A router that will use NAT and port forwarding to both protectA router that will use NAT and port forwarding to both protect
your home network and have another web server on your home networkyour home network and have another web server on your home network
while sharing the public IP address of ourfirewall.while sharing the public IP address of ourfirewall.
3. WhatWhat Is Iptables?Is Iptables?
Originally, the most popular firewall/NAT package running on Linux wasOriginally, the most popular firewall/NAT package running on Linux was
ipchains, but it had a number of shortcomings. To rectify this, the Netfilteripchains, but it had a number of shortcomings. To rectify this, the Netfilter
organization decided to create a new product called iptables, giving itorganization decided to create a new product called iptables, giving it
such improvements as:such improvements as:
●
Better integration with the Linux kernel.Better integration with the Linux kernel.
●
Stateful packet inspection.Stateful packet inspection.
●
Filtering packets.Filtering packets.
●
System logging.System logging.
●
Better network address translation.Better network address translation.
Considered a faster and more secure alternative to ipchains, iptables hasConsidered a faster and more secure alternative to ipchains, iptables has
become the default firewall package installed under RedHat and Fedorabecome the default firewall package installed under RedHat and Fedora
Linux.Linux.
4. Managing the iptables ServerManaging the iptables Server
Different Linux distributions use different daemon managementDifferent Linux distributions use different daemon management
systems.systems.
●
The most commonly used daemon management systems are SysVThe most commonly used daemon management systems are SysV
and Systemd.and Systemd.
●
The daemon isThe daemon is iptablesiptables..
Armed with this information we can know how to:Armed with this information we can know how to:
●
Start the daemons automatically on bootingStart the daemons automatically on booting
●
Stop, start and restart them later on during troubleshooting or when aStop, start and restart them later on during troubleshooting or when a
configuration file change needs to be applied.configuration file change needs to be applied.
5. Packet Processing In iptablesPacket Processing In iptables
All packets inspected by iptables pass through a sequence of built-in tablesAll packets inspected by iptables pass through a sequence of built-in tables
(queues) for processing.There are three tables in total.(queues) for processing.There are three tables in total.
➢
The first is the mangle table which is responsible for the alteration of qualityThe first is the mangle table which is responsible for the alteration of quality
of service bits in the TCP header.of service bits in the TCP header.
➢
The second table is the filter queue which is responsible for packet filtering.The second table is the filter queue which is responsible for packet filtering.
It has three built-in chains in which you can place your firewall policy rules.It has three built-in chains in which you can place your firewall policy rules.
These are the:These are the:
Forward chain: Filters packets to servers protected by the firewall.Forward chain: Filters packets to servers protected by the firewall.
Input chain: Filters packets destined for the firewall.Input chain: Filters packets destined for the firewall.
Output chain: Filters packets originating from the firewall.Output chain: Filters packets originating from the firewall.
➢
The third table is the nat queue which is responsible for network addressThe third table is the nat queue which is responsible for network address
translation. It has two built-in chains; these are:translation. It has two built-in chains; these are:
Pre-routing chain: NATs packets when the destination address of the packetPre-routing chain: NATs packets when the destination address of the packet
needs to be changed.needs to be changed.
Post-routing chain: NATs packets when the source address of the packetPost-routing chain: NATs packets when the source address of the packet
needs to be changedneeds to be changed
6. Check if iptables installedCheck if iptables installed
●
$ rpm -q iptables$ rpm -q iptables
iptables-1.4.7-5.1.el6_2.x86_64iptables-1.4.7-5.1.el6_2.x86_64
●
use the -L switch to inspect the currently loadeduse the -L switch to inspect the currently loaded
rules:rules:
# iptables -L# iptables -L
●
If iptables is not running, you can enable it byIf iptables is not running, you can enable it by
running:running:
# system-config-securitylevel# system-config-securitylevel
7. Switch OperationsSwitch Operations
-t <-table->-t <-table-> tables include: filter, nat, mangletables include: filter, nat, mangle
-j <target>-j <target> Jump to the specified target chain when the packet matchesJump to the specified target chain when the packet matches
the current rule.the current rule.
-A-A Append rule to end of a chainAppend rule to end of a chain
-F-F Flush. Deletes all the rules in the selected tableFlush. Deletes all the rules in the selected table
-p <protocol-type>-p <protocol-type> icmp, tcp, udp, and allicmp, tcp, udp, and all
-s <ip-address>-s <ip-address> source IP addresssource IP address
-d <ip-address>-d <ip-address> destination IP addressdestination IP address
-i <interface-name>-i <interface-name> "input" interface on which the packet enters."input" interface on which the packet enters.
-o <interface-name>-o <interface-name> "output" interface on which the packet exits"output" interface on which the packet exits
8. Targets And JumpsTargets And Jumps
●
ACCEPTACCEPT iptables stops further processing. The packet isiptables stops further processing. The packet is handed overhanded over toto
the end application or the operating system for processing.the end application or the operating system for processing.
●
DROPDROP iptablesiptables stopsstops further processing. The packet isfurther processing. The packet is blockedblocked..
●
LOGLOG The packet information is sent to the syslog daemon for loggingThe packet information is sent to the syslog daemon for logging
iptables continues processing with the next rule in the table.iptables continues processing with the next rule in the table.
●
REJECTREJECT Works like theWorks like the DROPDROP target, but will alsotarget, but will also return an errorreturn an error
messagemessage to the host sending the packet that the packet was blocked.to the host sending the packet that the packet was blocked.
●
DNATDNAT Used to doUsed to do destination network address translationdestination network address translation. ie. rewriting. ie. rewriting
the destination IP address of the packet.the destination IP address of the packet.
●
SNATSNAT Used to doUsed to do source network address translationsource network address translation rewriting the sourcerewriting the source
IP address of the packet. The source IP address is user definedIP address of the packet. The source IP address is user defined
●
MASQUERADEMASQUERADE Used to doUsed to do Source Network Address TranslationSource Network Address Translation. By default. By default
the source IP address is the same as that used by the firewall's interfacethe source IP address is the same as that used by the firewall's interface
9. InterfacesInterfaces
#iptables -A INPUT -i#iptables -A INPUT -i lolo -j ACCEPT-j ACCEPT
/*allows localhost/*allows localhost interfaceinterface 127.0.0.1*/127.0.0.1*/
#iptables -A INPUT -i#iptables -A INPUT -i eth0eth0 -j ACCEPT-j ACCEPT
/*allows eth0 which is our internal LAN connection, (eth0 and eth1 are ethernet/*allows eth0 which is our internal LAN connection, (eth0 and eth1 are ethernet
interfaces, they can be either internet or private network interfaces)*/interfaces, they can be either internet or private network interfaces)*/
#iptables -A INPUT -i#iptables -A INPUT -i ppp0ppp0 -j ACCEPT-j ACCEPT
/*allows ppp0 dialup modem which is our external internet connection*//*allows ppp0 dialup modem which is our external internet connection*/
10. Common Extended Match CriteriaCommon Extended Match Criteria
-m multiport --sports <port, port>-m multiport --sports <port, port>
A variety of TCP/UDP source ports separated by commas. Unlike whenA variety of TCP/UDP source ports separated by commas. Unlike when -m-m isn't used, they do notisn't used, they do not
have to be within a range.have to be within a range.
-m multiport --dports <port, port>-m multiport --dports <port, port>
A variety of TCP/UDP destination ports separated by commas. Unlike whenA variety of TCP/UDP destination ports separated by commas. Unlike when -m-m isn't used, they doisn't used, they do
not have to be within a range.not have to be within a range.
-m multiport --ports <port, port>-m multiport --ports <port, port>
A variety of TCP/UDP ports separated by commas. Source and destination ports are assumed to beA variety of TCP/UDP ports separated by commas. Source and destination ports are assumed to be
the same and they do not have to be within a range.the same and they do not have to be within a range.
-m --state <state>-m --state <state>
The most frequently tested states are:The most frequently tested states are:
ESTABLISHED:ESTABLISHED: The packet is part of a connection that has seen packets in bothThe packet is part of a connection that has seen packets in both
directionsdirections
NEW:NEW: The packet is the start of a new connectionThe packet is the start of a new connection
RELATED:RELATED: The packet is starting a new secondary connection. This is a commonThe packet is starting a new secondary connection. This is a common
feature of such protocols such as an FTP data transfer, or an ICMP error.feature of such protocols such as an FTP data transfer, or an ICMP error.
11. Accept packets from trusted IPAccept packets from trusted IP
addressesaddresses
●
To allow the packets from a single IPTo allow the packets from a single IP
iptables -A INPUT -iptables -A INPUT -ss 192.168.0.4 -192.168.0.4 -jj ACCEPTACCEPT
[-s source -j jump to the target action (here ACCEPT) ][-s source -j jump to the target action (here ACCEPT) ]
●
To allow incoming packets from a range of IP addressesTo allow incoming packets from a range of IP addresses
iptables -A INPUT -s 192.168.0.0/24 -j ACCEPTiptables -A INPUT -s 192.168.0.0/24 -j ACCEPT
oror
iptables -A INPUT -s 192.168.0.0/255.255.255.0 -j ACCEPTiptables -A INPUT -s 192.168.0.0/255.255.255.0 -j ACCEPT
12. Ports and ProtocolsPorts and Protocols
[ -p[ -p protocol (tcp,udp,icmp,all) ]protocol (tcp,udp,icmp,all) ]
[ -[ --dport-dport destination portdestination port ]] [--sport source port ][--sport source port ]
●
Accept tcp packets on destination port 6881 (bittorrent)Accept tcp packets on destination port 6881 (bittorrent)
#iptables -A INPUT -#iptables -A INPUT -pp tcp --tcp --dportdport 6881 -j ACCEPT6881 -j ACCEPT
●
To include a port rangeTo include a port range
Accept tcp packets on destination ports 6881-6890Accept tcp packets on destination ports 6881-6890
#iptables -A INPUT -p tcp --dport 6881:6890 -j ACCEPT#iptables -A INPUT -p tcp --dport 6881:6890 -j ACCEPT
13. Writing a Simple Rule SetWriting a Simple Rule Set
# iptables -# iptables -PP INPUT ACCEPTINPUT ACCEPT
//If connecting remotely we must first temporarily set the default//If connecting remotely we must first temporarily set the default policypolicy on theon the
INPUT chain to ACCEPT,otherwise we will be locked out of our server once weINPUT chain to ACCEPT,otherwise we will be locked out of our server once we
flush the current rules.flush the current rules.
# iptables -# iptables -FF
//to//to flushflush all existing rules so we start with a clean state from which to add newall existing rules so we start with a clean state from which to add new
rules.rules.
# iptables -A INPUT -i# iptables -A INPUT -i lolo -j ACCEPT //to communicate with the localhost-j ACCEPT //to communicate with the localhost
adaptor.adaptor.
# iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT# iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
//to allow only the incoming packets that are part of an already established connection or//to allow only the incoming packets that are part of an already established connection or
related to and already established connection.related to and already established connection.
14. Writing a Simple Rule Set (Contd.)Writing a Simple Rule Set (Contd.)
# iptables -A INPUT -p tcp --dport 22 -j ACCEPT# iptables -A INPUT -p tcp --dport 22 -j ACCEPT // to prevent accidental lockouts// to prevent accidental lockouts
when working on remote systems over an SSH connection.when working on remote systems over an SSH connection.
# iptables -P INPUT DROP# iptables -P INPUT DROP //if an incoming packet does not match one of the//if an incoming packet does not match one of the
following rules it will be dropped.following rules it will be dropped.
# iptables -P FORWARD DROP# iptables -P FORWARD DROP //set the default policy on the FORWARD chain to//set the default policy on the FORWARD chain to
DROP as we're not using our computer as a router so there should not be any packetsDROP as we're not using our computer as a router so there should not be any packets
passing through our computer.passing through our computer.
# iptables -P OUTPUT ACCEPT# iptables -P OUTPUT ACCEPT //set the default policy on the OUTPUT chain to//set the default policy on the OUTPUT chain to
ACCEPT as we want to allow all outgoing traffic (as we trust our users).ACCEPT as we want to allow all outgoing traffic (as we trust our users).
# iptables -L -v# iptables -L -v //we can list (-L) the rules we've just added to check they've been//we can list (-L) the rules we've just added to check they've been
loaded correctly.loaded correctly.
# /sbin/service iptables save# /sbin/service iptables save //to save our rules so that next time we reboot our//to save our rules so that next time we reboot our
computer our rules are automatically reloadedcomputer our rules are automatically reloaded
15. Masquerading (Many to One NAT)Masquerading (Many to One NAT)
Traffic from all devices on one or more protected networks will appear as if itTraffic from all devices on one or more protected networks will appear as if it
originated from a single IP address on the Internet side of the firewall.originated from a single IP address on the Internet side of the firewall.
echo 1 > /proc/sys/net/ipv4/ip_forward //to enable routing between internetecho 1 > /proc/sys/net/ipv4/ip_forward //to enable routing between internet
& private network interfaces of the firewall.& private network interfaces of the firewall.
Masquerading has been achieved using the POSTROUTING chain of the natMasquerading has been achieved using the POSTROUTING chain of the nat
table,table,
#iptables -A POSTROUTING -t nat -o eth0 -s 192.168.1.0/24 -d 0/0 -j#iptables -A POSTROUTING -t nat -o eth0 -s 192.168.1.0/24 -d 0/0 -j
MASQUERADEMASQUERADE
Use the FORWARD chain of the filter table. NEW and ESTABLISHEDUse the FORWARD chain of the filter table. NEW and ESTABLISHED
connections will be allowed outbound to the Internet,connections will be allowed outbound to the Internet,
#iptables -A FORWARD -t filter -o eth0 -m state --state#iptables -A FORWARD -t filter -o eth0 -m state --state
NEW,ESTABLISHED,RELATED -j ACCEPTNEW,ESTABLISHED,RELATED -j ACCEPT
But only packets related to ESTABLISHED connections will be allowed inbound.But only packets related to ESTABLISHED connections will be allowed inbound.
#iptables -A FORWARD -t filter -i eth0 -m state --state#iptables -A FORWARD -t filter -i eth0 -m state --state
ESTABLISHED,RELATED -j ACCEPTESTABLISHED,RELATED -j ACCEPT
This helps to protect the home network from anyone trying to initiateThis helps to protect the home network from anyone trying to initiate
connections from the Internetconnections from the Internet
16. Recovering From A Lost ScriptRecovering From A Lost Script
Sometimes the script you created to generate iptables rules may getSometimes the script you created to generate iptables rules may get
corrupted or lost, To recover:corrupted or lost, To recover:
Export the iptables-save output to a text file named firewall-configExport the iptables-save output to a text file named firewall-config
[root@bigboy tmp]# iptables-save > firewall-config[root@bigboy tmp]# iptables-save > firewall-config
[root@bigboy tmp]# cat firewall-config[root@bigboy tmp]# cat firewall-config
We can reload it into the active firewall rule set with the iptables-restoreWe can reload it into the active firewall rule set with the iptables-restore
command.command.
[root@bigboy tmp]# iptables-restore < firewall-config[root@bigboy tmp]# iptables-restore < firewall-config
[root@bigboy tmp]# service iptables save[root@bigboy tmp]# service iptables save
17. TroubleshootingTroubleshooting iptablesiptables
●
Checking The Firewall LogsChecking The Firewall Logs
LoLog and drop packets to the /var/log/messages file.g and drop packets to the /var/log/messages file.
iptables -A OUTPUT -j LOGiptables -A OUTPUT -j LOG
iptables -A INPUT -j LOGiptables -A INPUT -j LOG
iptables -A FORWARD -j LOGiptables -A FORWARD -j LOG
iptables -A OUTPUT -j DROPiptables -A OUTPUT -j DROP
iptables -A INPUT -j DROPiptables -A INPUT -j DROP
iptables -A FORWARD -j DROPiptables -A FORWARD -j DROP
18. Allowing DNS Access To Your FirewallAllowing DNS Access To Your Firewall
#iptables -A OUTPUT -p udp -o eth0 --dport 53 --sport 1024:65535 #iptables -A OUTPUT -p udp -o eth0 --dport 53 --sport 1024:65535
-j ACCEPT-j ACCEPT
#iptables -A INPUT -p udp -i eth0 --sport 53 --dport 1024:65535 #iptables -A INPUT -p udp -i eth0 --sport 53 --dport 1024:65535
-j ACCEPT-j ACCEPT
19. Allowing WWW And SSH Access ToAllowing WWW And SSH Access To
Your FirewallYour Firewall
●
Interface eth0 is the internet interfaceInterface eth0 is the internet interface
#iptables -A OUTPUT -o eth0 -m state --state ESTABLISHED,RELATED -j ACCEPT#iptables -A OUTPUT -o eth0 -m state --state ESTABLISHED,RELATED -j ACCEPT
●
Allow port 80 (www) and 22 (SSH) connections to the firewallAllow port 80 (www) and 22 (SSH) connections to the firewall
#iptables -A INPUT -p tcp -i eth0 --dport 22 --sport 1024:65535#iptables -A INPUT -p tcp -i eth0 --dport 22 --sport 1024:65535
-m state --state NEW -j ACCEPT-m state --state NEW -j ACCEPT
#iptables -A INPUT -p tcp -i eth0 --dport 80 --sport 1024:65535#iptables -A INPUT -p tcp -i eth0 --dport 80 --sport 1024:65535
-m state --state NEW -j ACCEPT-m state --state NEW -j ACCEPT
20. Allowing Your Firewall To Access TheAllowing Your Firewall To Access The
InternetInternet
●
Allow port 80 (www) and 443 (https) connections from the firewallAllow port 80 (www) and 443 (https) connections from the firewall
#iptables -A OUTPUT -j ACCEPT -m state --state NEW,ESTABLISHED,RELATED#iptables -A OUTPUT -j ACCEPT -m state --state NEW,ESTABLISHED,RELATED
-o eth0 -p tcp -m multiport --dports 80,443 --sport 1024:65535-o eth0 -p tcp -m multiport --dports 80,443 --sport 1024:65535
●
Allow previously established connectionsAllow previously established connections
Interface eth0 is the internet interfaceInterface eth0 is the internet interface
#iptables -A INPUT -j ACCEPT -m state --state ESTABLISHED,RELATED -i eth0#iptables -A INPUT -j ACCEPT -m state --state ESTABLISHED,RELATED -i eth0
-p tcp-p tcp
21. Allow Your Home Network To AccessAllow Your Home Network To Access
The FirewallThe Firewall
Allow all bidirectional traffic from your firewall to the protected networkAllow all bidirectional traffic from your firewall to the protected network
Interface eth1 is the private network interfaceInterface eth1 is the private network interface
#iptables -A INPUT -j ACCEPT -p all -s 192.168.1.0/24 -i eth1#iptables -A INPUT -j ACCEPT -p all -s 192.168.1.0/24 -i eth1
#iptables -A OUTPUT -j ACCEPT -p all -d 192.168.1.0/24 -o eth1#iptables -A OUTPUT -j ACCEPT -p all -d 192.168.1.0/24 -o eth1