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1500 questions
7
votes
1 answer

Mitigating a IPv6 malformed packet multicast flood

So we just had our first IPv6 multicast flood in the network this morning. We managed to stop the offending computer by blocking the mac address with: mac-address-table static x.x.x vlan x drop Before we blocked the mac address we started a…
mastrboy
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7
votes
3 answers

Is there any reason to use a hub over a switch?

Given that hubs are essentially the same as switches, as far as I know, except they share bandwidth between all connected devices, while switches do not, resulting in faster connections. I am simply wondering if there is any reasonable purpose for…
7
votes
2 answers

The best way to understand Vlans?

Every time i try reading about the configuration of a device and adding it to the network, i always face a problem. The problem is basically am not able to understand Vlan's, and how for example some companies use it: to move Voice over IP through…
7
votes
2 answers

Can Junos show a matching config statement in context, like IOS `| section`?

Hard to describe what I'm asking. For example, here's a section of my config, with the full hierarchy: interfaces { ge-0/1/9 { vlan-tagging; unit 100 { description "my cool interface"; vlan-id 100; …
Jacktose
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7
votes
2 answers

Dell PowerConnect 5524 VLAN routing

I have a Dell PowerConnect 5524 that I'm trying to configure. What I want is simple routing between VLANs and the user guide is less than helpful. On page 220, it says (or implies) that all you need to do to have routing enabled between two VLANs is…
Sean Airey
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7
votes
6 answers

Why do we need FTP when there are layers to transmit data?

In OSI, there are layers for routing, encapsulating and transmitting the data. Then why do we need FTP? I read the following definition of FTP in books: FTP is used for transferring files on networks. It isn't just a protocol; its also a program.…
7
votes
3 answers

How does NAT decide which connections are inbound, and which are outbound?

I'm building a P2P application that needs to be able to access nodes behind a NAT. This NAT does not allow inbound connections, therefore the nodes outside the network cannot reach out to the nodes behind the NAT. My solution to this problem is that…
Dean M.
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7
votes
1 answer

Router benefits in 2018 compared to a L3 Switch

What are the benefits nowadays to use a Router instead of a L3 Switch ?
bdes31
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7
votes
3 answers

Do low temperatures cause problems installing new optical wiring or fixing broken optical cables by splicing?

One of our supplier reported big problems splicing (using this) a broken outdoor optical fiber cable when temperatures around or little bellow freezing point. They refuse to install new optical fiber wires when temperatures are not well above zero…
Vojtěch Dohnal
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7
votes
3 answers

Difference between default route, partial and full routing table for a BGP session

What is the difference between default route, partial and full routing table for a BGP session? Does it affect the routes bird (or another BGP client connected to the session) sees?
Matthias Merkel
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7
votes
1 answer

Cisco IOS Tcl - Overhead

I've not been able to find much in regards to TCL other than the Cisco PDF "Cisco IOS Scripting with TCL Configuration Guide" and I just have a few queries. I'm looking into potentially utilising this for pinging a range of addresses withing a…
7
votes
3 answers

What are the components and licensing of a full Cisco CUCME PBX?

I've been placed in charge of replacing an older Avaya TDM PBX with a new VoIP system that will integrate with Exchange (at least in the capability to transcribe voicemail messages and deliver them to the email inbox). I recently acquired the CCNA…
WaxTrax
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7
votes
2 answers

Cisco 3064 switch upgrade from 6.0.x to 7.0.x issue

I am trying to upgrade from 6.0.2.U6.5c to nxos.7.0.3.I4.7, before upgrade i want to make sure it pass all checks but i got this error. This switch isn't in production yet but want to make sure it goes well and smooth. Am i doing something wrong?…
Satish
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7
votes
4 answers

Why preamble is not considered a part of the Ethernet Header?

If I search where does my data start in an Ethernet frame, I get a common answer which says TCP header( 20 bytes) + IP header ( 20 bytes) + Ethernet header( SA + DA + Type) i.e 14 bytes. So, in short the answer to that question becomes at 52-54…
7
votes
1 answer

Juniper SRX240H loses connectivity to upstream router

I have two SRX240's clustered together. The clustering is configured with 2 redundancy groups and then 3 RETH's. reth1 is connected to our internet connection via ge-0/0/5 and ge-5/0/5. Our internet connection is a 100mbps each way leased line. We…
Gareth Hastings
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