75 docs tagged with "network"

A descendant of the HOSTS.TXT file is the hosts file. On Linux, this file resides at /etc/hosts. It has a very simple syntax:

The iptables command can be broken into multiple pieces:

During system initialization, systemd launches a series of system-generators very early in the startup phase. These generators help with low-level setup on items.

Configuration

Transport Layer

Load Balancers

BIND

Cache hierarchies are further extending the caching idea. Groups of cache servers working in concert can increase the caching efficiency, route the traffic to the best link, and support a higher number of clients.

HTTP caches help reduce perceived lag, network utilization, and may improve performance of web applications. Caches can also be used as a filtering proxy, restricting access to certain sites or resources. Caches come in two flavors, forward and reverse.

Entries are kept in /etc/resolv.enf.

New/Change IP address

Simple Client Troubleshooting

- ethX: Ethernet devices.

ARP translates IPv4 addresses to MAC addresses

DNS Client/Resolver

The nameserver (DNS server) ordered list can be found here:

DNS Server Daemons

DNS Tools

The Domain Name System (DNS) is a distributed, hierarchical database for converting DNS names into IP addresses. The key-value store can be used for more than just IP address information. The DNS protocol runs in two different modes:

DNS is a distributed, hierarchical database for converting DNS names into IP addresses.

The Dynamic Host Configuration Protocol (DHCP) is used to configure the network-layer addressing. The dhcpd daemon used to be configured using both a configuration file (/etc/dhcp/dhcpd.conf) and a daemon options file that was distribution-dependent. Recent versions of dhcp have moved the daemon options into systemd.

Email programs and daemons have multiple roles and utilize various protocols.

Filter Table

A firewall is a network security system that monitors and controls network traffic. It applies to bot incoming and outgoing traffic. Can be implemented on HW and/or SW.

Forward/Reverse DNS Queries

Printing all socket information:

How to add network flakiness for testing applications.

How to Manage Active Network Connections

Layer 2 is about the hardware setting and examination of network adapters. We can use the following commands to modify the network adapter configuration:

Linux Containers (LXC) are an operating system type of virtualization. This operating system type of virtualization uses the Linux facilities of cgroups and namespaces. This allows virtualization of items like CPUs, memory, block I/O, networks, etc.

Get container ID (leftmost column)

Be aware that many details have been omitted and would be required to make this a functioning example.

Several command line utilities are available to manage the LXC containers:

For instance, enter dig hackers-arise.com and add the ns option (short for nameserver ). The nameserver for hackers-arise.com is displayed in the ANSWER SECTION of Listing 3-3 .

The three methods of mounting network filesystems (immediate mount -command line-; always mounted; and mounted on-demand) use a common configuration file /etc/fstab. Over the years, additional features and services have updated the options in /etc/fstab. Functionality that required external packages, services and configuration are now combined under systemd services.

Name resolution is translating hostnames to IP address.

Let me break down the options for your specific use case of capturing localhost HTTP traffic inside a Kubernetes Pod named pod-78db6d7fc-gtdk9 with a container named container.

netfilter is a packet-filtering framework built into the Linux kernel. To better understand netfilter, we need to start with some vocabulary:

Best command, will provide pid and name, listening, network stats:

IP addresses uniquely identify nodes across the internet. They are registered using an ISP.

Passive Network Traffic Capture

Network Enumeration Scripts

The iptraf tool is a RT. network traffic analyzer that recognizes the following protocols:

Many protocols require consistent, if not accurate time to function properly.

There are alternatives for network configuration, not just libvirt. The alternatives in the configuration of the network usually center around the selection of hypervisor. Network configuration for Virtual Machines and LXC containers can be created with:

Network File System is a filesystem protocol built upon the Open Network Computing Remote Procedure Call system (ONC RPC). RPCs are managed by the portmap service.

The Open Systems Interconnection (OSI) model was created to standardize the language used to describe networking protocols. It defines the manner in which systems communicate with one another using abstraction layers. Each layer communicates with the layer directly above and below. Not all layers are used at all times.

- Andrew File System (AFS) is a distributed, network filesystem built for high performance. OpenAFS is an open source branch of the original AFS now owned by IBM.

Traffic on interface eth0, with ASCII decoding,

When a browser fetches an https

Query/Record Types

Create a Socket Server

The dhclient command sends a DHCPDISCOVER request from the network interface specified (here, eth0 ). It then receives an offer ( DHCPOFFER ) from the DHCP server and confirms the IP assignment to the DHCP server with a dhcp request.

We can get the routing list of IP to device/interface:

The Server Message Block (SMB) protocol was originally designed at IBM and later incorporated as the de facto networking file/print sharing system for Microsoft Windows.

For advanced server troubleshooting, the /proc filesystem has settings that affect the network stack:

Print all socket information:

The main squid configuration file, squid.conf, can be found in the following locations:

Generate key

Set up sidecar container with tcpdump:

The TCP Wrappers system is a host-based network firewall and ACL. Originally, it only protected the inetd system, but has now been extended with the shared object library libwrap.

Test Connectivity with CA/certs

The most common errors found in setting up network filesystems are:

IP Configuration

Add the following flag:

VLANs use functionality in the switches and routers. The switch or router functionality must exist in the device as it is not usually an option that be added later.

Sets a filter for any packet with 10.0.0.1, as either the source or dest]