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#41
Home and Small Office Networking / The computer has rebooted from...
Last post by icecream-guy - February 16, 2024, 04:29:37 PMhow can I investigate this without forking out $$$ to Micros**t
from windows 11 system event log: today
The computer has rebooted from a bugcheck. The bugcheck was: 0x0000004e (0x0000000000000007, 0x00000000004d420e, 0x0000000000000001, 0x0000000000000000). A dump was saved in: C:\WINDOWS\Minidump\021624-37796-01.dmp. Report Id: af82ef39-64d8-405d-a293-0f0bc1a6fb9e.
I looked at the .dmp file with wordpad but it was all gibberish. Seems like I am hitting something like this every day now for the past week or so.
I did purchase Norton Utilities Ultimate last week, and it did clean up a bunch of crap on my computer.
maybe it's time to run SFC /scannow.
from windows 11 system event log: today
The computer has rebooted from a bugcheck. The bugcheck was: 0x0000004e (0x0000000000000007, 0x00000000004d420e, 0x0000000000000001, 0x0000000000000000). A dump was saved in: C:\WINDOWS\Minidump\021624-37796-01.dmp. Report Id: af82ef39-64d8-405d-a293-0f0bc1a6fb9e.
I looked at the .dmp file with wordpad but it was all gibberish. Seems like I am hitting something like this every day now for the past week or so.
I did purchase Norton Utilities Ultimate last week, and it did clean up a bunch of crap on my computer.
maybe it's time to run SFC /scannow.
#42
Certifications and Careers / Re: Certification Goals for 20...
Last post by deanwebb - February 14, 2024, 07:44:25 PMYeah, RHEL is the new CentOS, looks like. 
#43
Certifications and Careers / Re: Certification Goals for 20...
Last post by config t - February 14, 2024, 06:47:58 PMCrushed it this time. I want to do RHCA next since Forescout is shifting from CentOS back to red hat. I need to focus on zscaler for employer reasons though.
#44
Homework Help / Re: How does DHCP client knows...
Last post by config t - February 06, 2024, 09:32:42 PMQuote from: deanwebb on February 06, 2024, 09:39:19 AMThe network device that the client is attached to handles the DHCP request. The request is bound to a MAC address, so the network device makes sure that the request gets back to the device with that MAC address. In the case of multiple DHCP servers, the first to respond will be the one the client goes with.
To add to this; The network device handling the DHCP request, usually a switch, is the DHCP-Relay. It sends the layer 2 broadcast frames encapsulated as unicast UDP packets to the configured DHCP server(s). On a Cisco switch these are the "ip-helper" addresses configured on SVI.
DHCP service can also be configured locally on a device such as a router or L3 switch. We do this in cases where remote sites only have access to DHCP servers across unreliable or very low bandwidth WAN links that make UDP communication difficult.
#45
Homework Help / Re: How does DHCP client knows...
Last post by Otanx - February 06, 2024, 02:26:57 PMNot sure why your book says it is a broadcast. The ACK is a Unicast back to the client. However, even if it is a broadcast the DHCP packet contains the Client MAC address. See the Wireshark Wiki here: https://wiki.wireshark.org/DHCP
The first capture file on that page has a basic DHCP session. You can see the Discover and Request are both broadcasts. However, the Offer and Ack are both Unicast.
-Otanx
The first capture file on that page has a basic DHCP session. You can see the Discover and Request are both broadcasts. However, the Offer and Ack are both Unicast.
-Otanx
#46
Homework Help / Re: How does DHCP client knows...
Last post by networkloser - February 06, 2024, 10:55:57 AMThe next screen capture shows the Ethernet portion of the DHCP ack packet.
The Ethernet destination address is FFFFFFFFFFFF, which is the broadcast hard-
ware address, and the Ethernet source address is 005004744FFF, which is the
hardware address of the DHCP server
The DHCP portion of the DHCP ack packet contains information about the IP
address and the lease parameters. The following screen capture shows the DHCP
portion with all the DHCP options. After the DHCP client receives this acknowledg-
ment, then the client has an IP address. Now that the client has a valid lease on an
IP address, the client finishes building its TCP/IP stack.
Taken from TCP/IP foundations by andrew G blank
The Ethernet destination address is FFFFFFFFFFFF, which is the broadcast hard-
ware address, and the Ethernet source address is 005004744FFF, which is the
hardware address of the DHCP server
The DHCP portion of the DHCP ack packet contains information about the IP
address and the lease parameters. The following screen capture shows the DHCP
portion with all the DHCP options. After the DHCP client receives this acknowledg-
ment, then the client has an IP address. Now that the client has a valid lease on an
IP address, the client finishes building its TCP/IP stack.
Taken from TCP/IP foundations by andrew G blank
#47
Homework Help / Re: How does DHCP client knows...
Last post by deanwebb - February 06, 2024, 09:39:19 AMThe network device that the client is attached to handles the DHCP request. The request is bound to a MAC address, so the network device makes sure that the request gets back to the device with that MAC address. In the case of multiple DHCP servers, the first to respond will be the one the client goes with.
#48
Homework Help / How does DHCP client knows tha...
Last post by networkloser - February 06, 2024, 02:15:09 AMLet's discuss the "DORA" of DHCP.
1) Discover
Client broadcasts that "I want IP address".
Destination IP address=All 0s.
Destination hardware address=All Fs.
Source hardware address=DHCP Client address
2) Offer
Server/s makes an offer.
Destination hardware address=client's mac address
So that client knows the offer is for it.
It also should contain server's IP address/es.
3) Request
Client broadcasts DHCP request packet.
This includes,
DHCP Server's IP address so that other can cool down their IP address so client gets from who it wants.
Client's hardware address so that client hardware->IP address mapping can be done.
Destination address is All Fs, so that all hosts receive the notification.
4) Acknowledgement.
I am following TCP/IP foundations by Black and I'm confused how will the client know that the acknowledgement came for it?
1) Discover
Client broadcasts that "I want IP address".
Destination IP address=All 0s.
Destination hardware address=All Fs.
Source hardware address=DHCP Client address
2) Offer
Server/s makes an offer.
Destination hardware address=client's mac address
So that client knows the offer is for it.
It also should contain server's IP address/es.
3) Request
Client broadcasts DHCP request packet.
This includes,
DHCP Server's IP address so that other can cool down their IP address so client gets from who it wants.
Client's hardware address so that client hardware->IP address mapping can be done.
Destination address is All Fs, so that all hosts receive the notification.
4) Acknowledgement.
I am following TCP/IP foundations by Black and I'm confused how will the client know that the acknowledgement came for it?
#49
Home and Small Office Networking / Re: General network architectu...
Last post by deanwebb - February 02, 2024, 09:32:43 AMThat's a broad question. Generally, architecture is a description of the solutions in place and how they interact. There's a level of detail to the documentation for a solution:
Architectural Handbook (AH): a high-level view of the solutions, providing guiding principles for the deployment. Should initial design choices run into difficulties, use the AH to provide guidance in how best to resolve those difficulties.
High Level Design (HLD): Details hardware and software to be acquired along with licensing, where it will go, how it will be rolled out, and system settings to be used.
Low Level Design (LLD): Specifies on an interface level how things are to be connected. Often a set of network diagrams with explanatory notes.
In the Americas, the documents tend to be brief. In Europe, they tend to be larger and more wide-ranging.
That being said, the architecture for you scenario would specify the order the devices mentioned would be arranged. We'd want to know more about whether those are running on separate platforms or on the same one. Also, is this for accessing an external-facing application that is exposed to the Internet, or is this for access to an internally-hosted application that is not otherwise exposed to the Internet? Those answers will determine how the pieces fall together.
To boost architecture skills, ask more questions and get more answers. Architecture involves learning about many different technologies so that you have a range of tools to draw upon when asked to solve for a particular business case.
Architectural Handbook (AH): a high-level view of the solutions, providing guiding principles for the deployment. Should initial design choices run into difficulties, use the AH to provide guidance in how best to resolve those difficulties.
High Level Design (HLD): Details hardware and software to be acquired along with licensing, where it will go, how it will be rolled out, and system settings to be used.
Low Level Design (LLD): Specifies on an interface level how things are to be connected. Often a set of network diagrams with explanatory notes.
In the Americas, the documents tend to be brief. In Europe, they tend to be larger and more wide-ranging.
That being said, the architecture for you scenario would specify the order the devices mentioned would be arranged. We'd want to know more about whether those are running on separate platforms or on the same one. Also, is this for accessing an external-facing application that is exposed to the Internet, or is this for access to an internally-hosted application that is not otherwise exposed to the Internet? Those answers will determine how the pieces fall together.
To boost architecture skills, ask more questions and get more answers. Architecture involves learning about many different technologies so that you have a range of tools to draw upon when asked to solve for a particular business case.
#50
Home and Small Office Networking / General network architecture f...
Last post by networkloser - February 01, 2024, 02:21:36 AMWhat is the general architecture of a network that comprises of Web Application Firewall(F5), Firewall, VPN, reverse proxy(nginx)?
I am new to this field and I am wondering what the architecture in general looks like? And where can I learn more about this? Any courses or certification exams that I can do to boost my network architecture skills?
I am new to this field and I am wondering what the architecture in general looks like? And where can I learn more about this? Any courses or certification exams that I can do to boost my network architecture skills?