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5 answers

Why is the ICMP protocol considered to run at layer 3 on the Wikipedia page?

Why is the ICMP protocol considered to run at layer 3 on the Wikipedia page (same layer as IP) when the ICMP protocol data is a payload of the IP packet? This is the article on Wikipedia that states that ICMP is in the same layer as IP protocol. I…
yoyo_fun
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Is 'switchport protected' supposed to block unicast flooding?

Does having switchport protected configured on an interface prevent unicast flooding for a MAC address the switch hasn't learned? The information that I'm seeing conflicts -- the wikipedia page on unicast flooding cites protected mode as a mechanism…
Shane Madden
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9
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2 answers

Find idle connections in Check Point firewall

I have a firewall, where I have to lower the TCP session timeout from 24h to 1h. Before I do that, I'm trying to determine if this will break any applications, i.e applications that have sessions that can be idle for a long time, but are not able to…
sk0yern
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9
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3 answers

Using latency to calculate OSPF metrics

Is it possible to configure OSPF to use latency in its link cost/metric calculations. The idea being to enable performance based routing whereby the fastest and least congested links in the network will be chosen dynamically, rather than relying on…
PeterD
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9
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1 answer

switchport block multicast vs storm-control multicast

I'm not sure what is the difference in behaviour between switchport block multicast and storm-control multicast and I don't think cisco elaborates the difference very well in their documentation, other than the fact storm-control grants you levels…
CaseyJones
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1 answer

Why does a Cisco AP keep its static IP when erasing NVRAM?

When I erase the nvram on a Cisco AP (1252 and 1262), the static IP assigned to interface BVI1 is not erased. When I do a show startup-config it says there is no startup config. But it always boots with that IP until I manually set it to DHCP…
some_guy_long_gone
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9
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1 answer

Problems Connecting Catalyst 2960G to Netgear Prosafe Via Fibre

I've got a catalyst 2960G, connected to a Netgear Prosafe GS718T switch (cheap manageable switch). Idea is I have a couple of users that need access to a test environment - hence the cheap switch. It's connected via fibre through a 1Gbit SFP over…
user1411
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4 answers

What use are MAC addresses?

I know that MAC addresses are used in networks for several things, e.g. static fixed IP addresses assigned by DHCP servers or for Wireless access points. But why is it necessary in the Internet? Let's say I send a packet to someone not on my local…
hgiesel
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EIGRP FD not the same in topology table

In EIGRP when showing topology table, i notice in some entries are like below: P 10.1.6.0/24, 1 successors, FD is 793600 via 10.1.2.2 (2195456/281600), Serial0/0/0 via 10.1.3.2 (77081600/281600), Serial0/0/1 It seems the…
user1559625
9
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3 answers

10 Gb blade question

I am debating with a colleague about a potential configuration. We are implementing a new blade solution that has a built in 10 Gb switch and two blade servers, each having 4 10 Gb NICs. However, the rest of our environment is still 1 Gb. The blade…
Ryan
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9
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4 answers

Advantage of layer 3 switch over Router

What is the advantage of Layer 3 switch over the Router ??
Abiral
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9
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3 answers

Cisco NAT hairpinning

I have a Cisco router configured NAT (4 static NAT and dynamic NAT). My problem is that I can't access internal servers using public IP addresses from the internal network. I know what the problem is. I did a lot of Google searching about this…
sareeshmnair
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9
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2 answers

Why do summary routes get a low Administrative Distance?

Why do summary routes get a lower AD than other routing protocols? For example: The AD of EIGRP is 90, whereas the AD of a summary route is 5.
Abiral
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9
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4 answers

SCP lost connection

Occasionally I have an issue when I try to SCP a file to one of our Cisco devices. When the connection starts, it immediately drops and says "lost connection". I've had this happen when there wasn't enough space on the flash drive but this isn't the…
some_guy_long_gone
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9
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2 answers

Switch-Assisted Load Balancing w/ Fault Tolerance

While studying for Cisco and Microsoft certifications I read a lot about NIC Teaming, Etherchannels and similar stuff. I know you can do static teaming in MS Windows Server or creating a port-channel in Cisco or use Dynamic protocols such as LACP…
Alex
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