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Network Analysis

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The collection of articles, videos, and posts on this topic.

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Network analysis is the process of identifying and remediating the processes and systems within a network, including performance, connectivity and security. The process is performed through the use of tools developed for monitoring and analyzing network activity. Network problems that involve finding an optimal way of doing something are studied under the name combinatorial optimization. Examples include network flow, shortest path problem, transport problem, transshipment problem, location problem, matching problem, assignment problem, packing problem, routing problem, Critical Path Analysis and PERT (Program Evaluation & Review Technique).

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hi folks

i am wondering if anyone ever used Cisco WRVS4400N's port mirroring feature to monitor traffic of a given port?

i have tried any individual port or even all ports together as the source, but i still cannot see any mirrored traffic from listening to the specific port (Port 4), as shown below.

Screen-Shot-2017-09-13-at-13.29.04.png
i have no idea why the device doesn't work as expected. do you have any suggestion please?

regards,
bbao
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8 Comments
Concerto Cloud for Software Providers & ISVs
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Concerto Cloud for Software Providers & ISVs

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I want to record all unsuccessful login attempts in Kiwi Syslog, is it possible?
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3 Comments
Has anyone used a free bandwidth monitor.  We can't afford the ones that are out there that cost.

Any help would be appreciated.
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3 Comments
Hi, we are in work group environment, using cisco c3925 as the router facing Internet. How can we know the Internet pages where users access? Do you know any free tool or devices? Many thanks.
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5 Comments
Hello ,

I have 2 questions about timestamp ;

1. I have try to convert time stamp value to normal time but it was returned anormal dates :) what is the format of this TS val ?
2. As far as i read on the http://www.networksorcery.com/enp/protocol/tcp/option008.htm 


This field is only valid if the ACK bit is set in the TCP header.


but nearly all SYN packets in normal traffic not a DDOS has TSval  while ack was not sScreen-Shot-2017-08-27-at-18.05.41.pnget
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3 Comments
Hello

I have a couple of WAN connections and used by few users to access company services like : Mail,Web Applications...etc.
Both Lines have "A" Records with our ISP. if one line is down,  is it possible to redirect the users to access services through the back up line ? or can you suggest best scenario ?

Best Regards
Mahmoud
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7 Comments
My "server1" Windows 2012 R2 has two NICs, with two static IPs, 192.168.20.10 and 192.168.37.10

When ping  "server1" from a client on the 192.168.20.x it replies with the 192.168.37.10 IP and says it cannot find it

How can I get "server1" to reply as 192.168.20.10 instead ?
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5 Comments
I have encountered a security breach, the most likely explanation is packet sniffing of http data. The issue is that we have many companies each assigned to their own separate VLANs. Can packet sniffers sniff across different Vlans if they are connected to the same  the same switch or AP? I didn't think that was possible?
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7 Comments
In the search tool - you can select source or destination address that EQUALS, NOT EQUALS, IS EITHER, IS NEITHER. But what I haven't figured out is how to search by subnet. e.g. show me all the traffic with Destination in the 10.12.67.0/24 subnet. Is that possible?
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3 Comments
I have a single workstation on the domain that everyday brings the network to a halt by utilizing the entire bandwidth for the office.  The report from solarwinds shows:  Se0/0/0       216.58.193.174  Gi0/1         -internal ip-     06 01BB C453  7771K.  Any ideas on how to troubleshoot this issue?  I did not find any malware on the workstation, and during most of the traffic burst time the user is not at the keyboard.
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6 Comments
Simple, centralized multimedia control
Simple, centralized multimedia control

Watch and learn to see how ATEN provided an easy and effective way for three jointly-owned pubs to control the 60 televisions located across their three venues utilizing the ATEN Control System, Modular Matrix Switch and HDBaseT extenders.

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How set equally load balancing for 3 different ISPs

Please find the exsting config, after this configuration i am unable to get load balancing in order, always traffice goes automaticly from interface FastEthernet0/0/0 every time i dont know why its happing.

Maximum time uses:-
interface FastEthernet0/1 - 20% (4Mbps Link)
interface FastEthernet0/0/0 - 30% (2Mbps LInk)
interface FastEthernet0/0/1  - 50% (2Mbps LInk)

why every time traffice use primery interface as a interface FastEthernet0/0/1, please suggest what need to be changes for traffice move in order, example:-
interface FastEthernet0/1 - 60% (4Mbps Link)
interface FastEthernet0/0/0 - 20% (2Mbps LInk)
interface FastEthernet0/0/1  - 20% (2Mbps LInk)

Router 1 Config:-

interface FastEthernet0/0
 description office_64/5/10_Lan
 ip address 192.168.90.1 255.255.255.0
 ip flow ingress
 duplex auto
 speed auto
!
interface FastEthernet0/1
 description 4Mbps
 ip address 1.1.1.1 255.255.255.0
 delay 1
 duplex auto
 speed auto
!
interface FastEthernet0/0/0
 description 2Mbps
 ip address 2.2.2.1 255.255.255.0
 delay 2
 duplex auto
 speed auto
!
interface FastEthernet0/0/1
 description 2Mbps
 ip address 3.3.3.1 255.255.255.0
 delay 3
 duplex auto
 speed auto
!
!
router eigrp 100
 variance 2
 network 1.1.1.0 0.0.0.3
 network 2.2.2.0 0.0.0.3
 network 3.3.3.0 0.0.0.3
 network 192.168.90.0

Router 2 Config:-

interface FastEthernet0/0
 description Rack_Lan
 ip address …
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1 Comment
Hello Experts, I need some assistance since I'm not that familiar with SonicWall

I have a TZ215 FW with both, LAN and WLAN active configurations, I upgraded my ISP BW from 10Mbps to 20Mbps (cable provider) and just realized that everything connected to the LAN interfaces on my sonicwall (X0) are getting the full 20Mbps (or really near with speedtest.net) but all my wireless clients only get up to 10Mbps...

Does anyone has any idea of what is going on here?

Thanks for your support
1
25 Comments
In this article, we’ll look at how to deploy ProxySQL.
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0 Comments
I set up a Linksys LRT224 router about a year ago
it does some pass-throughs ti the following
-security camera NVR only two users can access

-Windows Server 2012 running an SQL database about 10 users

-VPN connection so users can get to all servers and appliances
This was suppose to be for only two users, but now they want all 10 users to be able to use VPN

Question?
should I continue to use this router? will is start to degrade in speed
some users say the VPN is starting to slow down

any suggestions are appreciated
0
4 Comments
I have an HP EliteBook 8730w HP machine with XP SP3.  The NIC is a 82567LM Gigabit.  Wireshark Version 1.6.1 is seeing a flood (packet ea/.001068 seconds +/-) of protocol 0x8899 Ethernet II packets (All outgoing; no responses).  Packet length ranges from 64 to about 1499 or 1518 packets long. The problem I have is that I cannot find the Source MAC on my (small home) network (I have tried several MAC scanners), nor do I know anything about the destination address.

Source:  f8:c0:01:7c:65:cc
Destination: Dell_79:08:f2 (00:19:b9:79:08:f2)
Type: Unknown (0x8899), Ethernet II
Data (1504 bytes)
5 lines of data:
0010   88 64 11 00 14 ef 05 d6 00 21 45 40 05 d4 ac 25  .d.......!E@...%
0020   20 00 36 11 54 58 47 13 fb f9 61 73 b9 db a0 e1   .6.TXG...as....
0030   c9 be 05 cd 4b 14 32 bb 81 3a 22 b9 5d 95 21 4e  ....K.2..:".].!N
0040   6d 27 cb 53 59 65 0b 8d 75 33 cb ab f9 de 7e 52  m'.SYe..u3....~R
0050   32 57 86 24 53 27 ee 64 20 41 72 31 20 11 2a 43  2W.$S'.d Ar1 .*C
.
.

So, I have no such source or destination MAC on my network (that I can tell) , am seeing  an ongoing flood  of data anytime day/night.  To my knowledge, I have no Dell equipment on my network (two printers, 4-5 computers, a couple of Smart phones, and several Security DVRs).  Most computers behind one or more switches.  I am certain that I have no Realtek routers/switches or anything that might be using a managed protocol i.e. Realtek Remote Control Protocol (RRCP) Type 0x8899.
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12 Comments
We are having some "unspecified network issues" between a Windows Vista and Windows 10 computer.  

As we are trying to eliminate causes one by one.  The ping times between these two wired computers will go from less than 1ms up to 15ms with 90%+ of the them being single digits or below 1ms.  

Is this normal?
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3 Comments
How can I test the speed between two computers on the network?
0
4 Comments
Can someone please recommend a good SNMP monitoring software - preferably free
0
5 Comments
Looking for a application I caN check out my network to see if there is a issue in loss of connects delays slow connection and if, which point and what application. Any recommendations but not something that should break my pocket.
0
5 Comments
NEW Veeam Agent for Microsoft Windows
LVL 1
NEW Veeam Agent for Microsoft Windows

Backup and recover physical and cloud-based servers and workstations, as well as endpoint devices that belong to remote users. Avoid downtime and data loss quickly and easily for Windows-based physical or public cloud-based workloads!

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Hello,

We are pinging a network device from a Lunix computer and see there is an indication of packet drops - see screenshot.  

I disconnect the network cable of the ping target device and I do not any ping response to that IP.  

What can I do to troubleshoot?

Thanks.
packetlost.png
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3 Comments
We currently have a Dell Sonic Firewall that is our firewall as well as our company router.  This is our main router for all of our sites in the company.  We have 16.  We implemented through our EMR (Electronic Medical Records) software an upload to a billing company.  They in turn configure and print bills and send them out to our customers.  This has worked fine for over two years.  When this was implemented, we were not required to make any firewall changes at all.

A week ago, the user doing this procedure received an error that the file could not be uploaded.  She called the EMR company, who in their effort to troubleshoot the problem, changed the upload method from ftp to sftp.  She then tried to upload and she got an additional error that port 22 was unable to send.  Seeing that error, the EMR said that the problem has to do with our firewall.  I spoke with the billing company who tried to do a trace route to our external IP.  They were unsuccessful, but I was able to do a trace route to them.  The only caveat is that the user can do this procedure from home with no problem.

I am willing to make firewall changes if necessary, I just don't know what they would be or why it is necessary now, if no one has made any changes other than the upload method from ftp to sftp.

Please help.  I am desperate.
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27 Comments
what is the difference between nagios and centreon, are they technically both the same
0
2 Comments
How to monitor services on your network and why?
Monitoring a network: how to monitor network services and why? Michael Kulchisky, MCSE, MCSA, MCP, VTSP, VSP, CCSP outlines the philosophy behind service monitoring and why a handshake validation is critical in network monitoring. Software utilized in this video is NetCrunch network monitor, available at adremsoft.com.
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0 Comments
Network monitoring: how to automate fixing common network or server issues?
Michael from AdRem Software outlines event notifications and Automatic Corrective Actions in network monitoring. Automatic Corrective Actions are scripts, which can automatically run upon discovery of a certain undesirable condition in your network. This brief tutorial shows where to find this feature in NetCrunch network monitor and gives you real-case scenarios where Automatic Corrective Actions can be utilized to automate fixing common network or server problems.
0
0 Comments
I'm sure I have done something wrong here. This is such a basic config. Can you tell me why my router can communicate outside, but my PCs cannot?

!
! Last configuration change at 17:48:41 UTC Sat Jun 10 2017
!
version 15.1
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname MYROUTER
!
boot-start-marker
boot-end-marker
!
enable secret 5 <obscured>
enable password <obscured>
!
no aaa new-model
!
no process cpu extended history
no process cpu autoprofile hog
memory-size iomem 20
dot11 syslog
ip source-route
no ip routing
!
!
!
!
no ip cef
no ip domain lookup
!
multilink bundle-name authenticated
!
!
!
!
!
license udi pid CISCO1841 sn FTX1104Z0BG
!
redundancy
!
!
! 
!
!
!
!
!
!
interface FastEthernet0/0
 description OUTSIDE
 ip address dhcp
 ip nat outside
 no ip virtual-reassembly
 duplex auto
 speed auto
 no cdp enable
!
interface FastEthernet0/1
 description INSIDE
 ip address 172.16.254.1 255.255.255.0
 ip flow ingress
 ip nat inside
 ip virtual-reassembly
 no ip route-cache
 speed auto
 half-duplex
 no cdp enable
 no mop enabled
!
interface ATM0/0/0
 no ip address
 no ip route-cache
 shutdown
 no atm ilmi-keepalive
!
ip forward-protocol nd
no ip http server
no ip http secure-server
!
!
ip nat inside source list 101 interface FastEthernet0/0 overload
ip route 0.0.0.0 0.0.0.0 dhcp
!
access-list 101 permit ip any any
no cdp run

!
!
!
snmp-server community public RO
!
!
control-plane
!
!
line con 0

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18 Comments

Network Analysis

9K

Solutions

19

Content

i
The collection of articles, videos, and posts on this topic.

12K

Contributors

Network analysis is the process of identifying and remediating the processes and systems within a network, including performance, connectivity and security. The process is performed through the use of tools developed for monitoring and analyzing network activity. Network problems that involve finding an optimal way of doing something are studied under the name combinatorial optimization. Examples include network flow, shortest path problem, transport problem, transshipment problem, location problem, matching problem, assignment problem, packing problem, routing problem, Critical Path Analysis and PERT (Program Evaluation & Review Technique).

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