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1500 questions
19
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2 answers

Can a probe request be answered on a different channel?

I am monitoring the 802.11 traffic in my network, and especially the active probing from my smartphone. I am sending Probe Requests for certain hidden SSIDs, but also an Undirected Probe Request, supposed to reveal networks matching the capabilities…
olamotte
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2 answers

Cause of high CPU load on Juniper peering router's routing engine

Recently the routing engine CPU utilization on two of our Juniper peering routers increased from ~10-20% average load to 80+%. I'm trying to figure out what's causing this (and how to get this high load back down). Some info on the routers: both run…
Teun Vink
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19
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4 answers

Bad Mask for IP Address Error

I'm not too clear on subnetting rules and experienced an error when I tried to assign 148.26.1.176/28 to an interface on my Cisco router. Can someone please explain why it was not allowing me to assign this address to the interface? I receive an…
THE DOCTOR
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19
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8 answers

What is real difference between host and node in network

According to wikipedia host is A network host is a computer or other device connected to a computer network. A network host may offer information resources, services, and applications to users or other nodes on the network. A network host is a…
apm
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19
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3 answers

Is the "default VLAN" simply the default native (untagged) VLAN on all interfaces that have no configuration?

... or does the "default VLAN" have some wider meaning? Also, can it / should it be changed? For instance, if a switch is going into part of a network that is only one VLAN and it's not VLAN 1, is it possible to make the "default" / native VLAN on…
Matty Brown
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19
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2 answers

How does the router know how to route the packets to my terminal?

Suppose I have a network of 2 computers, each having a private network address of 192.168.1.101 and 192.106.1.102. For my public ip address, it is 10.2.10.172. When I make a http request to google.com, my computer will send out a packet with source…
Mc Kevin
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19
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3 answers

What factors drive a Cisco IOS upgrade?

In order of preference/priority, what factors do you consider in driving an upgrade (or downgrade) with Cisco IOS? If no compelling factors exist, how long would you allow a particular version of IOS to stay running? I've seen some switches with…
generalnetworkerror
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19
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3 answers

What is the difference between all the switching modes on 6500/7600?

On one of my routers, I see the following switching modes: #show fabric switching-mode Global switching mode is Truncated dCEF mode is not enforced for system to operate Fabric module is not required for system to operate Modules are allowed to…
Aaron
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19
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4 answers

Jumbo Ethernet Frame Deployment

What are some general guidelines for the successful deployment of jumbo frames in a routed environment?
Dennis Olvany
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19
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2 answers

Traceroute - every packet has TTL == 1

I'm working on Wireshark lab-IP in Computer networking - A top down approach and I don't understand why every packet that normally expired has a TTL of 1. Here is my Wireshark capture…
ksp0422
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18
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6 answers

How are IP addresses mapped to MAC addresses?

I've been reading about the differences between MAC and IP addresses, and why we need both of them. To summarize, MAC addresses are physical unchangeable unique IDs for every single device while IP addresses are assigned, changeable and virtual. To…
CodyBugstein
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18
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1 answer

Why do some common traceroute implementations default to using UDP probes?

I was recently troubleshooting a network connectivity meta-problem, in that I knew a given destination was reachable, but I was not able to demonstrate that with traceroute because the path went cold after a certain number of hops. Given that the…
neirbowj
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18
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3 answers

How do you know if a Cisco switch is handling traffic well?

I have just read Jeremy's question about 2960-S and iSCSI traffic handling, which drove me to ask this question: We all have lots of switches deployed in distinct infrastructures, how can you know that the traffic is treated well? I usually check…
laf
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18
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4 answers

MAC address recycling?

Something I've always wondered about is MAC address exhaustion. Do hardware vendors keep track of MAC address allocation to their platforms, and then subsequently "reclaim" MAC addresses when a product goes EOL, and then re-use them on a new…
John Jensen
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18
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4 answers

Are there any reasons to not use BFD?

In looking to implement Bidirectional Forwarding Detection (BFD) it seems to be very flexible in terms of timer tuning, light weight regarding any overhead and it's flexibility in terms of overall application appears very impressive. So if for…
MattE
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