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1500 questions
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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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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…
Anshul Choudhary
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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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ASR920 and output drops - surprisingly, IPTV seem to work okay

Maybe my question will be a bit unusual because I will not ask why something doesn't work. Instead, I will ask why things seem to work okay. I have ASR-920-24SZ-IM connected to upstream ASR9ks with 2x10G links. Downstream device is cisco 4948E…
mkurek
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What is the voltage used in ethernet lines (UTP Cables)?

I am asking this because after doing some research I found some conflicting information. First, on Wikipedia page on Ethernet physical layer I found that the voltage on the lines is 2.5V. https://en.wikipedia.org/wiki/Ethernet_physical_layer But in…
yoyo_fun
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What is the difference between "ip domain name" and "ip domain-name"?

I'm running a ISR 4221 with "Cisco IOS XE Software, Version 16.04.02". I see that it has both ip domain name and ip domain-name commands. Why? Is this some sort of compatibility thing? My 7206 seems to prefer ip domain-name. Just…
Erik Bennett
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2 answers

Manager states we cannot put retail switches on network due to fear of non-STP config and network storm problems. Is this true?

I'm a desktop support engineer working with a Cisco certified manager. I value her opinion greatly when it comes to networking issues. However, I'm split on this because with my knowledge of networking (granted not as much as hers) I don't see how…
Jason
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2 answers

NAT Overlapping

I am trying to do some networking lab. Basically, I have a network like this: So, is it possible to configure NAT router in such way, that PC1 and PC2 can access remote HOST and each other. The problem for me is that PC1 and PC2 have same local ip…
mcferden
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4 answers

How to make IPSEC over double NAT?

I need to have a site to site VPN between two sites. Here is the following topology for each site: Site A: One Cisco 1921 WAN port (192.168.3.2) connected to ISP router (192.168.3.66), both the Cisco 1921 and the ISP's router are doing NAT…
Moh'ed A-Nasir Dhagajuun
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4 answers

What exactly is the difference between SDN & NFV?

What is the difference between SDN (Software Defined Networking) & NFV (Network Function Virtualization)? Wikipedia says NFV relies on standard client-server model. How is this model different than Data plane-Controller plane model? Please explain…
Nullpointer
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New VLAN across multiple Cisco switches

I have setup a new VLAN on my corporate network for use for guests only. I am trying to setup a guest WiFi service and keep all of the traffic separate from the business traffic. So far I have created a 172.16.0.0/24 subnet using VLAN 172 for…
Becky
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7
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3 answers

How does the ISP connect me to the Internet?

I know its a dummy question, but I couldn't find any information about it around the Internet. I know about modems and routers and how they work, but I don't get how the ISP connects me to the internet? I mean... How do ISP's communicate with…
user34853
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4 answers

Building too large for ethernet runs

I'm pretty new to network design. I know enough to wire small buildings and such, but I'm puzzled as to how work this one out. A building I'm working on is an odd shape, and very large. Unfortunately, it is too large for standard cat5e. I certainly…
user34833
7
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2 answers

Cisco ASA: Why does static NAT block access through VPN?

TL/DR I set up a static nat rule, so that I can use my public internet IP address to directly ssh into a dedicated machine on the inside network. As a result I cannot ssh into the dedicated machine anymore, when connected through AnyConnect VPN.…
user1129682
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4 answers

iBGP AS path prepend propogation

I have following scenario: My AS: 64501 has two routers R3 (Redundand) and R4 (Main). ISP AS: 64500 has 3 routers R1, R2 and R5 I have eBGP peering with ISP, I have no access to ISP configuration, only to configuration on my net (R3, R4). I need…
DmitriiGangan
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