linux
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linux [2019-08-07 T 17:22] admin [Network RHLE] |
linux [2022-03-28 T 19:07] (current) admin [dig] |
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| Normally after changing this you can do this to reset it. There are a few ways to do this. | Normally after changing this you can do this to reset it. There are a few ways to do this. | ||
| - | ====ifdown and ifup== | + | ====restart network interface==== |
| + | There are a few different ways to restart the interface and depending on your system you may need to use different ones. this is also very helpful for running scripts. | ||
| + | ===ifdown and ifup=== | ||
| This command is a simple way to enable and disable and interface | This command is a simple way to enable and disable and interface | ||
| * $ifdown [options] [iface] | * $ifdown [options] [iface] | ||
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| Or another is to use the -a for all | Or another is to use the -a for all | ||
| * $ifdown -a && ifup -a | * $ifdown -a && ifup -a | ||
| - | ====Alternative restart network interface | ||
| Sometimes ifdown and ifup do not work so you may need to do other commands to restart the network service. | Sometimes ifdown and ifup do not work so you may need to do other commands to restart the network service. | ||
| + | === Debian systemctl=== | ||
| + | This is for systems that use systemctl, but it does not always work: | ||
| + | sudo systemctl restart networking.service | ||
| ===invoke-rc.d=== | ===invoke-rc.d=== | ||
| This will perform a restart at the high level of processes. it is effective | This will perform a restart at the high level of processes. it is effective | ||
| invoke-rc.d networking restart | invoke-rc.d networking restart | ||
| - | This is for systems that use systemctl, but it does not always work: | + | |
| - | sudo systemctl restart networking.service | + | |
| ==== Network RHLE ==== | ==== Network RHLE ==== | ||
| Redhat, centos, etc have a bit different method | Redhat, centos, etc have a bit different method | ||
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| netmask 255.255.255.0 | netmask 255.255.255.0 | ||
| vlan-raw-device bond0 | vlan-raw-device bond0 | ||
| + | ===Links=== | ||
| + | https:// | ||
| + | ====Checking network configuration==== | ||
| + | this page indicates some checks that could be done after configuring the interfaces file. https:// | ||
| + | \\ Mainly it suggests to perform these checks: | ||
| + | * ifconfig to look that interfaces are configured properly | ||
| + | * mii-tool (not sure how this will work) | ||
| ==== ip ==== | ==== ip ==== | ||
| Use ip to show / manipulate routing, devices, policy routing and tunnels. Many of the things you do with ifconfig can now be done with ip. Here is a good link, and some examples that will be expanded uppon later. | Use ip to show / manipulate routing, devices, policy routing and tunnels. Many of the things you do with ifconfig can now be done with ip. Here is a good link, and some examples that will be expanded uppon later. | ||
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| </ | </ | ||
| * Please note that DNS is Auto generated via network manager. So if you change it but have nm running, it will override any changes to this file upon the next reboot. | * Please note that DNS is Auto generated via network manager. So if you change it but have nm running, it will override any changes to this file upon the next reboot. | ||
| - | ==== Vlan ==== | + | |
| - | Here is a basic idea behind adding vlans. This is not comprehensive | + | |
| - | * be sure your network card is compatable with the 802.1q standard. | + | |
| - | * Make sure the VLAN modual is loaded To check do: | + | |
| - | * $lsmod | grep 8021q | + | |
| - | * If not loaded, you can do: | + | |
| - | * $modprobe 8021q | + | |
| - | * You can add vlans mainly with 2 commands: | + | |
| - | * $ip link add link eht0 name eth0.100 type vlan id 100 | + | |
| - | * or | + | |
| - | * $vconfig add eth0 5 | + | |
| - | * vconfig may requrire a package not standard. in Advanced Package Tool its simply called vlan | + | |
| - | There are several other ways and types of configurations we will add to this later. | + | |
| - | ===remove vlan=== | + | |
| - | you can remove a vlan with something like: | + | |
| - | * $ip link delete eth0.100 | + | |
| ==== Network Manager Service ==== | ==== Network Manager Service ==== | ||
| Network manager or nm is a very common service running to manage networks and give an easy to use gui for network releated operations in linux. It is very common with many distros and perfect for easily connectng wifi or changing IP. | Network manager or nm is a very common service running to manage networks and give an easy to use gui for network releated operations in linux. It is very common with many distros and perfect for easily connectng wifi or changing IP. | ||
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| * -D to list available interfaces | * -D to list available interfaces | ||
| * -n does not resolve name servers, useful if in a slow devices | * -n does not resolve name servers, useful if in a slow devices | ||
| + | * -e Shows Mac address | ||
| * src [ip] / dst [ip] shows you lines with that source or desitnation ip respectivly. | * src [ip] / dst [ip] shows you lines with that source or desitnation ip respectivly. | ||
| * proto [protocal] for types of packages | * proto [protocal] for types of packages | ||
| Line 1083: | Line 1079: | ||
| sudo tcpdump -i eth0 ether host aa: | sudo tcpdump -i eth0 ether host aa: | ||
| This is an excellent page for more options: https:// | This is an excellent page for more options: https:// | ||
| + | ==== dig=== | ||
| + | Use dig to easily lookup what the DNS entry of an ip is. | ||
| + | dig [host] [options] | ||
| + | Some options | ||
| + | * +short to just show the IP address entry | ||
| + | Example to look up what IP google has and what Ip it returns: | ||
| + | User@mend: | ||
| + | 142.251.46.238 | ||
| ==== SSH ==== | ==== SSH ==== | ||
| ssh stands for secure shell. It is a service that allows for you to remote access a terminal using encryption. It is very universally standard and exists on most linux systems or can be easly installed | ssh stands for secure shell. It is a service that allows for you to remote access a terminal using encryption. It is very universally standard and exists on most linux systems or can be easly installed | ||
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| * $wget -qO- http:// | * $wget -qO- http:// | ||
| This will call up a website that can display your ip in a simple way. The operators for wget are just quiet and save to a standard file which is then echoed with the echo command. | This will call up a website that can display your ip in a simple way. The operators for wget are just quiet and save to a standard file which is then echoed with the echo command. | ||
| - | ====snmp==== | + | ====SNMP==== |
| + | Simple Network Management Protocol allows you to get information from network devices. You can also use it to control, but this is not the typical way it is used. | ||
| + | * OID is the address of a specific date point that can be used when querying a network device with SNMP. | ||
| + | * MIB is the Management information base, and is usual a file formatted a specific way to indicated what OIDs mean what. The device itself does not necessarily have identifiers of what each OID means. | ||
| + | * ASN1 is Abstract Syntax Notation One. This is the Syntax that MIBs are in. | ||
| + | * Agent - Is the device queering the client device for data using various types of SNMP gathering software | ||
| + | * Community - The agent uses the community string to Authenticate that it can gather information from devices. Note that this is a low security model in version 1 and 2c of snmp | ||
| + | * SNMP version 1 and 2c. Version 2c allows for more expansion of what data can be passed with SNMP, and some other improvements, | ||
| + | * SNMP version 3 adds extra security and authorization beyond just knowing the community | ||
| + | To install the suite of packages | ||
| * The package name in ubuntu/ | * The package name in ubuntu/ | ||
| * The package name in Centos/RHEL is net-snmp | * The package name in Centos/RHEL is net-snmp | ||
| - | === snmpwalk === | + | === snmpstatus=== |
| + | To get the status of if snmp and if it is running on a device you need to know the IP of the host, the community string, and the version | ||
| + | | ||
| + | For example | ||
| + | | ||
| + | === snmpwalk | ||
| snmpwalk is a tool to scan for snmp. To install you you just install the package called snmp | snmpwalk is a tool to scan for snmp. To install you you just install the package called snmp | ||
| snmpwalk [opts] -c [community] [ip address] [OID] | snmpwalk [opts] -c [community] [ip address] [OID] | ||
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| * -m "[mib file]" This will tell snmp walk to look up the mib file. The defualt MIB search path is several paths defined by the : / | * -m "[mib file]" This will tell snmp walk to look up the mib file. The defualt MIB search path is several paths defined by the : / | ||
| * You can put in the OID address at the end to just get data from that data point | * You can put in the OID address at the end to just get data from that data point | ||
| + | snmpwalk will go through every sub OID possible from the highest point you are calling it from. This is very good when discovering sets of data, but if you want to find the specific information of a specific OID, you want to try snmpget. This is very hepful because if you use walk for what you think is specific OID. It might append a 1 or another number on the end. For example, lets say that oid.99.500.3.5 is supposed to tell you how may foos are in the network device so you run: | ||
| + | snmpwalk -v1 -c public 192.168.1.99 oid.99.500.3.5 | ||
| + | You might get a return of: | ||
| + | SNMPv2-SMI:: | ||
| + | You can see that in the readout it shows the oid with a .1 on the end. So if you did snmpget instead: | ||
| + | snmpget -v1 -c public 192.168.1.99 oid.99.500.3.5 | ||
| + | This might be a return readout: | ||
| + | SNMPv2-SMI:: | ||
| + | If you do walk, you may see that the o | ||
| ===snmpd=== | ===snmpd=== | ||
| To allow your linux device to act as a simple snmp agent you can install snmpd | To allow your linux device to act as a simple snmp agent you can install snmpd | ||
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| * http:// | * http:// | ||
| * http:// | * http:// | ||
| + | * https:// | ||
| + | * http:// | ||
| ==== iperf ==== | ==== iperf ==== | ||
| Iperf is a way of transferring bulk benign files to see pure transfer rates. Here is a good tuturial: [[http:// | Iperf is a way of transferring bulk benign files to see pure transfer rates. Here is a good tuturial: [[http:// | ||
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| * -p shows PID | * -p shows PID | ||
| * -n shows numerical addresses instead of trying to determine symbolic host, port, or user names | * -n shows numerical addresses instead of trying to determine symbolic host, port, or user names | ||
| + | ====SSL Cert==== | ||
| + | A secure socket layer certificate is used to authenticate a website with various authorities that give out certificates. It allows for a url to operate has https within a browser or any service that accesses that domain. This is not really a network tool, but rather a security tool for domains within a network. | ||
| + | ===Cert basics and location=== | ||
| + | A certificate is a file with an encryption key. It uses public key cryptography between the web client, like your browser, and the server, or the website you are trying to access with https. The file is located in a few different locations depending on what system you have. Ultimately though you will be defining where the file is with the httpd.conf file. More about that below | ||
| + | ===Obtain cert=== | ||
| + | First you must obtain the cert. Certs can be found with some hosting providers like godadd, or with a free service like https:// | ||
| + | ===conf file=== | ||
| + | There is an ssl.conf file but that just has to do with paramiters of how you want ssl to work. You will need to locate the httpd.conf file and make sure that your cert files are pointed to the right locations. here is an example / | ||
| + | SSLCertificateFile / | ||
| + | SSLCertificateKeyFile / | ||
| + | SSLCertificateChainFile / | ||
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| Some aspects of linux involve modifying the kernal moduals that are loaded. | Some aspects of linux involve modifying the kernal moduals that are loaded. | ||
| ==== Modprobe ==== | ==== Modprobe ==== | ||
| - | This will add or remove | + | This will add, remove or modify |
| - | === beep === | + | |
| - | Using modprobe | + | A simple way to see if a specific module is installed is to do: |
| - | http:// | + | lsmod | grep [module] |
| ====== Processes and Services ====== | ====== Processes and Services ====== | ||
| Init management is how linux manages processes and when they start, such as at startup. There is a lot of complexity and difference in this system, but the 2 most common commands for managing startup are: | Init management is how linux manages processes and when they start, such as at startup. There is a lot of complexity and difference in this system, but the 2 most common commands for managing startup are: | ||
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| To exit: | To exit: | ||
| * Ctl + a + x (can do as holding ctl, press a, release a, press x) | * Ctl + a + x (can do as holding ctl, press a, release a, press x) | ||
| + | === Remove computer beep === | ||
| + | Using modprobe to remove the computer beep: http:// | ||
| + | modprobe beep | ||
| ====== Packages Services ====== | ====== Packages Services ====== | ||
| The following are very popular packages used in many Linux administration systems. | The following are very popular packages used in many Linux administration systems. | ||
linux.1565198557.txt.gz · Last modified: 2019-08-07 T 17:22 by admin
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