Apple 034-2351_Cvr manual Preventing Denial-of-Service DoS Attacks

Page 59

Common Network Administration Tasks That Use Firewall Service

Your firewall is the first line of defense against unauthorized network intruders, malicious users, and network virus attacks. There are many ways that such attacks can harm your data or use your network resources. This section lists a few of the common uses of firewall service in network administration.

Preventing Denial-of-Service (DoS) Attacks

When the server receives a TCP connection request from a client to whom access is denied, by default it sends a reply rejecting the connection. This stops the denied client from resending over and over again. However, a malicious user can generate a series of TCP connection requests from a denied IP address and force the server to keep replying, locking out others trying to connect to the server. This is one type of Denial- of-Service attack.

To prevent ping denial-of-service attacks:

1In Server Admin, choose Firewall from the Computers & Services list.

2Click Settings.

3Select the General tab.

4Select the Any address group.

5Deselect “ICMP Echo (ping) reply.”

6Click Save.

Important: Denial-of-Service attacks are somewhat rare, so make these settings only if you think your server may be vulnerable to an attack. If you deny ICMP echo replies, services that use ping to locate network services will be unable to detect your server.

Controlling or Enabling Peer-to-Peer Network Usage

Sometimes network administrators need to control the use of Peer-to-Peer (P2P) file sharing applications. Such applications might use network bandwidth and resources inappropriately or disproportionately. P2P file sharing might also pose a security or intellectual property risk for a business.

You can cut off P2P networking by blocking all traffic incoming and outgoing on the port number used by the P2P application. You’ll have to determine the port used for each P2P network in question. By default, Mac OS X Server’s firewall blocks all ports not specifically opened.

You can choose to limit P2P network usage to IP addresses behind the firewall. To do so, you’ll need to open the P2P port for your LAN interface, but continue to block the port on the interface connected to the Internet (WAN interface). To learn how to make a firewall filter, see “Creating an Advanced IP Filter for TCP ports” on page 51.

Chapter 3 IP Firewall Service

59

Page 58 Page 60
Image 59
Page 58 Page 60
Contents Mac OS X Server Network Services Administration 034-2351/9-20-03 Contents Glossary Index What’s Included in This Guide How to Use This GuideUsing This Guide Getting Additional Information Setting Up Mac OS X Server for the First TimeGetting Help for Everyday Management Tasks Before You Set Up Dhcp Service Dhcp ServiceLocating the Dhcp Server Using Static IP AddressesCreating Subnets Assigning IP Addresses DynamicallyAssigning Reserved IP Addresses Setting Up Dhcp Service for the First TimeUsing Multiple Dhcp Servers on a Network Interacting With Other Dhcp ServersSet up logs for Dhcp service Managing Dhcp ServiceStarting and Stopping Dhcp Service Creating Subnets in Dhcp ServiceTo change subnet settings Changing Subnet Settings in Dhcp ServiceChanging IP Address Lease Times for a Subnet Deleting Subnets From Dhcp ServiceSetting the DNS Server for a Dhcp Subnet To set Ldap options for a subnet Setting Ldap Options for a SubnetSetting Wins Options for a Subnet Viewing the Dhcp Status Overview Monitoring Dhcp ServiceDisabling Subnets Temporarily Viewing the Dhcp Client List Setting the Log Detail Level for Dhcp ServiceViewing Dhcp Log Entries Where to Find More Information DNS Service DNS and Bind Before You Set Up DNS ServiceSetting Up DNS Service for the First Time Setting Up Multiple Name ServersLearn and plan Start DNS service Configure basic DNS settingsSet up a mail exchange MX record optional Configure the reverse lookup zone optionalEnabling or Disabling Recursion Managing DNS ServiceStarting and Stopping DNS Service Enabling or Disabling Zone TransfersAdding a Master Zone Managing ZonesTo add a slave zone Adding a Slave ZoneTo add a master zone To duplicate a zone Adding a Forward ZoneDuplicating a Zone To add a forward zoneTo modify a zone Managing RecordsModifying a Zone Deleting a ZoneTo add a record Adding a Record to a ZoneTo delete a record Modifying a Record in a ZoneDeleting a Record From a Zone To modify a recordViewing DNS Log Entries Viewing DNS Service StatusViewing DNS Service Activity Monitoring DNSTo change the log detail level Changing DNS Log File LocationViewing DNS Usage Statistics To see DNS usage statistics Securing the DNS ServerDNS Spoofing Server MiningTo alter BIND’s version response DNS Service ProfilingDenial-of-Service DoS To specify zone transfer IP addressesService Piggybacking Example.com Common Network Administration Tasks That Use DNS ServiceSetting Up MX Records Edit the MX record of the primary mail server Configuring DNS for Mail ServiceTo enable MX records Enabling Redundant Mail ServersTo enable backup or redundant mail servers Setting Up Namespace Behind a NAT RouterNetwork Load Distribution aka Round Robin Setting Up a Private TCP/IP NetworkWhat Is BIND? Configuring Bind Using the Command LineHosting Several Internet Services With a Single IP Address Zone Data Files Bind Configuration FileBind on Mac OS X Server Practical ExampleConfiguring Clients Setting Up Sample Configuration FilesTo set up the sample files Check Your Configuration Using DNS With Dynamically Assigned IP AddressesIf you are using Mac OS X Server as your Dhcp Server Request For Comment Documents For more information on DNS and BIND, see the followingPage IP Firewall Service IP Firewall Service Subnet Mask What is a Filter?Understanding Firewall Filters IP AddressCidr Multiple IP Addresses Using Address RangesRule Mechanism and Precedence Add filters to the IP filter list Setting Up Firewall Service for the First TimeStart firewall service Create an IP address group that filters will apply toSave firewall service changes Managing Firewall ServiceStarting and Stopping Firewall Service Opening the Firewall for Standard ServicesTo create an address group To open the firewall for standard servicesCreating an Address Group To edit or delete an address group Editing or Deleting an Address GroupDuplicating an Address Group Creating an Advanced IP Filter for TCP portsTo create an IP filter for TCP ports Creating an Advanced IP Filter for UDP PortsTo create an IP filter for UDP ports NFSTo edit advanced IP filters Changing the Default FilterTo change the Default setting Editing Advanced IP FiltersViewing the Firewall Log Monitoring Firewall ServiceSetting Up Logs for Firewall Service Viewing the Firewall Status OverviewTo view denied packets Viewing Denied PacketsViewing Packets Logged by Filter Rules Log ExampleTo do this Block Access to Internet UsersPractical Examples Block Junk MailAllow a Customer to Access the Apple File Server Controlling or Enabling Peer-to-Peer Network Usage Preventing Denial-of-Service DoS AttacksTo prevent ping denial-of-service attacks Background Advanced ConfigurationControlling or Enabling Network Game Usage Creating IP Filter Rules Using ipfw PrecautionsCreating IP Filter Rules Reviewing IP Filter RulesDeleting IP Filter Rules Port ReferencePptp VPN UDP port Used for Reference For more information about ipfw To start NAT service NAT ServiceStarting and Stopping NAT Service Viewing the NAT Status Overview Configuring NAT ServiceMonitoring NAT Service To configure NAT serviceFor more information about natd To view the NAT divert logPage VPN Service Point to Point Tunneling Protocol Pptp Authentication MethodVPN and Security Transport ProtocolsEnabling and Configuring L2TP Transport Protocol Before You Set Up VPN ServiceManaging VPN Service Starting or Stopping VPN ServiceTo enable Pptp Enabling and Configuring Pptp Transport ProtocolTo enable L2TP To set routing definitions Configuring Additional Network Settings for VPN ClientsConfiguring VPN Network Routing Definitions To configure addition network settingsViewing a VPN Status Overview Monitoring VPN ServiceSetting the Log Detail Level for VPN Service Setting the VPN Log Archive IntervalTo view client connections Viewing the VPN LogViewing VPN Client Connections To view the logPage How NTP Works NTP ServiceTo set up NTP service Using NTP on Your NetworkSetting Up NTP Service To configure NTP on clients Configuring NTP on ClientsPage IPv6 Support Notation IPv6 Enabled ServicesIPv6 Addresses in the Server Admin IPv6 AddressesIPv6 Address Types IPv6 Reserved AddressesIPv6 Addressing Model Where to Find More Information Glossary GlossaryGlossary Glossary Name server See DNS Domain Name System Search path See search policy UCE unsolicited commercial email See spam Glossary Page Index Dhcp VPN

034-2351_Cvr specifications

The Apple 034-2351_Cvr is a remarkable product designed to enhance the user experience for various Apple devices. Known primarily as a protective cover, the 034-2351_Cvr is tailored to meet the demands of both functionality and style.

One of the main features of the 034-2351_Cvr is its premium materials that provide durability while maintaining a lightweight profile. Made from high-quality polycarbonate and soft-touch silicone, the cover not only protects devices from scratches and minor drops but also offers a comfortable grip. The edges of the cover are reinforced to absorb shocks, ensuring your device remains secure under everyday use.

Another defining characteristic is the precise cutouts and tailored design that allows for seamless access to all ports and buttons. Users can easily charge their devices, utilize speakers, and access buttons without needing to remove the cover. This focus on user accessibility aligns perfectly with Apple’s ethos of simplicity and ease of use.

In terms of technology, the 034-2351_Cvr features advanced features that cater to modern-day needs. It provides compatibility with wireless charging, ensuring that users can charge their devices without the hassle of removing the cover. This convenience is especially valuable for users who travel frequently and rely on wireless charging solutions.

Additionally, this cover incorporates antimicrobial properties, helping to reduce the growth of bacteria on its surface. This is increasingly important for users who are aware of hygiene, especially during a time when sanitization has become a priority in everyday life.

Design-wise, the 034-2351_Cvr is available in a range of colors and finishes, allowing users to personalize their devices according to their style. Whether one prefers a sleek matte look or a vibrant glossy finish, there is an option to suit every aesthetic.

Furthermore, the cover is designed to fit securely without adding bulk, preserving the slim profile of the device it protects. This maintains the sleek Apple design language while offering essential protection.

In conclusion, the Apple 034-2351_Cvr is more than just a protective accessory. With its combination of high-quality materials, advanced technologies, and stylish design, it embodies the essence of modern device protection, making it an essential accessory for Apple device users.
Top Page Image Contents