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1500 questions
6
votes
2 answers
how to find the right value of MTU Jumbo frame
we take the decision to set jumbo frame on all our linux machines
we have hadoop cluster with master machines , workers machines and kafka machines
our switches ( Cisco ) are suitable to Jumbo frame and that fine
but jumbo frame can set as 8000 or…
yael
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6
votes
1 answer
CIDR notation and subnets
I've been given a script that will create a virtual network with the following IP range (in Azure): 10.0.0.0/16.
The script then goes on to create two subnets within that network with the following IP ranges: 10.0.5.0/24 and 10.0.6.0/24. My…
Adam
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- 4
6
votes
3 answers
Why does a pure ACK increment the sequence number?
I cannot figure out why a pure ACK will increment the sequence number of the sending host by 1 when the TCP segment contains only a header, such as in the third segment in a three-way handshake for establishing a TCP connection.
For example:
Host1…
user44362
6
votes
2 answers
What are the correct protocol versions (v4 vs v6) for packets inside DS-Lite tunnels?
I work for a company that develops Deep Packet Inspection tools. One of our customers, big ISP who has a large number of DS-Lite connected subscribers, was using our DPI engine to collect statistics on IPv4 and IPv6 usage in their network. It was…
Piotr S.
- 63
- 4
6
votes
2 answers
What MAC address do I use to generate a IPv6 Pseudo-Random Global ID
I am setting up a virtual lab environment in the cloud to experiment with IPv6 networks.
Bear with me please, I'm new to networking and my grasp of the whole IPv6 subject is quite shaky. Please correct me if I misunderstand any of the IPv6 concepts…
snrrn
- 163
- 6
6
votes
3 answers
Does a switch always get a MAC address from a PC?
I was wondering if there is a possibility that a switch won't get the needed MAC address to it's CAM.
For example, if the used protocol is UDP, where the sender doesn't need an answer back from the receiver?
Thank you
Lukáš Stacke
- 63
- 3
6
votes
3 answers
what's the difference between tag-based and Port-based VLAN and which one is better?
what's the difference between tag-based and Port-based VLAN and which one is better ?
Med Mtiri
- 61
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- 2
6
votes
1 answer
A FEX port remains inactive - how can I bring it up?
When implementing Cisco Nexus 5k switches (5596UP), I connected a server to a dual homed 2000 FEX (2232T), the port belonging to a virtual port channel. However, the port changed the status from notconnected to inactive and remained so.
I verified…
Stefan
- 3,384
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6
votes
4 answers
Why are static IP addresses considered a bad practice?
Im looking to better understand this piece of advice in relation to setting up devices on internal networks with static IP addresses, and why that is considered a bad idea.
On the surface of it, setting up static IP addresses for devices on an…
BruceJohnJennerLawso
- 185
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- 6
6
votes
1 answer
iperf: send specific volume?
I wanted to test some different test cases. I wanted to transmit 1MB, 10MB, 100MB, ..., 1GB, ... and measure bandwith with iperf.
In the manual stands that I can use a combination of -l and -n parameter.
So now I want to send for example 1 MB.
I use…
user674907
- 73
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- 1
- 4
6
votes
1 answer
What's use of Port Isolation vs traditional VLANs?
I've seen several switch products advertising port isolation feature as "way to limit ports communication without configuring VLANs" and it sounds quite... sketchy? If i understand it correctly port isolation allows you to literally specify which…
Lapsio
- 231
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- 9
6
votes
1 answer
How do you configure a TACACS+ tac_plus server on Ubuntu 16.04 that authenticates against Microsoft Active Directory?
How do you configure a TACACS+ tac_plus server on Ubuntu 16.04 that authenticates against Microsoft Active Directory?
dt1235
- 151
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6
votes
1 answer
Calculate the FCS number from a frame ethernet
I've the following frame ethernet:
08 00 20 0A 70 66 08 00 20 0A AC 96 08 00 45 00 00 28 A6 F5 00 00 1A 06 75 94 C0 5D 02 01 84 E3 3D 05 00 15 0F 87 9C CB 7E 01 27 E3 EA 01 50 12 10 00 DF 3D 00 00 20 20 20 20 20 20 9B 52 46 43
Where 0x9B524643 is…
Davide
- 175
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- 1
- 5
6
votes
3 answers
Lab: I need to determine information about a device on a specific port of a Cisco multilayer switch
I have a Cisco Catalyst that has a port that is up up, and the device does not show in the ARP table. The MAC address-table shows a MAC address for the port. What can I do from that switch to find out what the device is?
Kendrick
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- 11
6
votes
1 answer
The use of DMZ and single firewall design
Apologies in advance if this is a stupid question. I have just started exploring network designs and firewalls.
I have come across a network design where there is single firewall between internet, DMZ and the internal network.
From my…
DefenderAtkins
- 61
- 1
- 2