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6 votes
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Multiple VLANs with same subnet behind single ASA

Depending on the ASA and license you have, you could use contexts which create virtual ASAs within the ASA. Each is independent of the other. This would also allow you to test ASA configs before ...
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5 votes
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GNS3: performance tests using iperf3?

Don't trust GNS3 for throughput tests. As soon as you use a router in your topology you are likely only to get 5mb/sec tops, regardless of whether you use a serial, ethernet or fast ethernet interface ...
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4 votes

How to extensively test an ethernet switch

Judging by your switch, I'd say you don't have the budget for a real ethernet tester like those from Fluke Networks. Your switch is Layer 2 (L2) only and doesn't support routing, so you'd need an ...
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4 votes

Feeding a PoE capable device with variable power supply over TIA568 A cable (DC spares)

The PSE decides on which pairs power is supplied. A compliant PD needs to be able to use either pairs. Connecting a power supply to the spare pairs (only possible with 10BASE-T and 100BASE-TX) is not ...
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  • 71.5k
4 votes

What are the most common scenarios in which the 'loopback interface' on a router is used?

A loopback interface is a virtual (i.e. not physical) interface that never goes down, unless you disable it. This way, if you configure an IP on this loopback interface and add it to your OSPF area (...
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  • 1,677
4 votes

What are the most common scenarios in which the 'loopback interface' on a router is used?

...we learned that every router has a LOOPBACK interface. That is not true. Cisco routers can be configured with loopback interfaces, but they don't have loopback interfaces until you create one. ...
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4 votes
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Is there a network cable tester device that tests the cables with realistic frequency instead of on/off leds?

What you're looking for is a cable tester able to certify a cable with the entire test suite. The tests must include crosstalk and detailed frequency measurement. Basically, there are three classes of ...
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  • 71.5k
3 votes
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Iperf results on UDP Bandwidth

There is one particularity about iperf 2.0.x with UDP: Within the limits (CPU, NIC, UDP/IP stack and its buffers) of the sending system, iPerf will send traffic at the payload rate you specify with ...
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3 votes
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What binary prefix, JEDEC or IEC, is used for calculating networking gear speed

EDITED Despite the extended usage of binary in computer world and power of two based units (Byte, 32-bits word etc...), network bandwidth is commonly expressed in power of ten units. So it is (...
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  • 18.4k
3 votes
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Testing local network speed

iPerf or Tamosoft throughput test. As a primarily Mac shop I currently find TTT more convenient, as iPerf builds for Mac are somewhat limited to specific OS versions or "build it yourself". TTT is a ...
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  • 2,736
3 votes
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How do testers (i.e. Fluke) get the port they're connected to?

I'm almost 100% positive that for Cisco switches it would be CDP (Cisco Discovery Protocol) while on other vendors, they would use the industry standard LLDP (Link Layer Discovery Protocol). From CDP, ...
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3 votes

How to extensively test an ethernet switch

There are a few problems with your premise. First, connecting switch ports to switch ports will either end up disabling the switch ports or causing a spanning-tree loop. Switches send BPDUs to ...
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  • 94.1k
3 votes

Firewall Benchmark- Concurrent connection metrics

For metrics you can look in to the reports that NSS labs are publishing, they have pretty solid documentation on how they do firewall testing. You can also google for their reports, sometimes firewall ...
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3 votes

Iperf 'set bandwidth' command issues

I'm inclined to believe that it is your caps/non-caps on the bandwidth designations (i.e. -b 10M -l 32K -w 128K). I can't test it because we don't know what version you're running. Iperf does make a ...
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  • 5,449
3 votes
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What does "inline" mean in the context of cable testing?

“Inline” refers to PoE, not to the position of the tester. So this with this tester you can check cables doing power over Ethernet. You would still place the tester at the ends of the cable.
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  • 15.7k
2 votes

Accurate strategy for measuring point-to-point link performance?

Since you are wanting to measure a layer 2 circuit, I'd like to shamelessly push some free software that I have been writing. It's still in beta but does exactly what you want based on the information ...
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  • 5,270
2 votes

Wireless network testing software

useful tool can help you to make good wireless survey is wifi analyzer on the android phones. its can work on both ranges 2.4 and 5 GHZ you can use it to figure out channel utility and it DPI and ...
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  • 3,414
2 votes

Do routers and networks have have a "max threads" configuration?

You may be confused about something. You application may create threads for execution on your PC, but routers switch packets one at a time, regardless of what came before, and routers have no ...
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  • 94.1k
2 votes

What is the difference between uplink and downlink (JMeter)?

in terms of server and client communications . based on stream or traffic traffic going from the server to the clients called downstream , and from clients to server called upstream . based on device ...
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  • 3,414
2 votes
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Confused about the results from the cable tester

I offer another interpretation: 4 wire cable for 100Mbit/s. This is basically the same as zac67's answer "Either it's a bad LSA contact, a bad panel insert or a damaged cable.", but probably the ...
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2 votes

Confused about the results from the cable tester

A cable tester of that type injects a pulse into the cable and analyzes the time it takes to reflect back. That tester can't really test/certify a cable deployment (you'd need attenuation, NEXT/FEXT, ....
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  • 71.5k
2 votes

How to test if an sfp is working on juniper qfx5100

Check the manual/datasheets - both the switch and the transceiver should state what they're compatible with. If you're using a range of different optics it makes a lot of sense to maintain a ...
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  • 71.5k
2 votes

WiFi TCP iperf throughput: upstream vs down stream

While passing downlink traffic (from the Access Point (AP)) to client-nodes, the AP schedules the packets from the packet-queues in the appropriate way and also does not face any contention on the ...
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  • 56
2 votes
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How to use IXIA IxNetwork 8.40 to send bi-directional traffic between CPE and router

It took about 10 seconds to search the Internet to find this: To configure NAT translation in regular testing, all you have to do is open “Network Neighbourhood,”(In case you need a quick recap ...
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  • 94.1k
2 votes

iperf3 UDP tuning

That's how iperf3.x works. The "client" wants to establish a control channel to the "server" before any UDP transfer is started. That's why you can observe some TCP before the UDP ...
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1 vote
Accepted

How to test the maximum of clients connected to an AP?

From what I know there are no upper limits in the 802.11 protocol. There are software limits in some of the AP's I've worked with. Aerohive usually have 100 concurrent stations on most AP's. The way ...
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  • 58
1 vote

How to duplicate multicast source over several multicast addresses

A multicast group is a destination IP address on an IP packet. The destination IP address is determined by the sender, and modifying an IP address on a packet is called NAT (Network Address ...
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  • 94.1k
1 vote
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How to test outoing traffic on random ports? (on OS X)

Use a program like NMAP to determine what ports are open to what addresses. Security operations(assuming your network has a security team) may not appreciate this as it will look suspicious when you ...
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1 vote

Simulate a proxy or server that is silently dropping pooled tcp connections?

You could put in a router with NAT or a firewall between, and set the TCP timeout to be very low. Alternatively, you could try to correct the situation by using TCP keepalive. This will periodically ...
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  • 94.1k
1 vote

How can I test my ping application for proper detection of ICMP return types and codes

Take a look at scapy: http://www.secdev.org/projects/scapy/ and tcpdump/wireshark. With the former you can generate any ICMP packet, with the later you can see what your generated packets look like. ...
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