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Questions tagged [security]

A general purpose tag to mark discussions of general security topics including firewalls, ACLs, AAA and numerous others related to keeping the network safe from unauthorized access.

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0answers
68 views

How to proceed for research on Network security? [closed]

It may out of scope but I have to research on Network security. I have worked on Signal Processing in Time-Frequency down during Post Graduation research and have few publication. Now my interest ...
3
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1answer
865 views

CCP Running issue

I already have installed CCP. but when I run it, it gives this message: Cisco configuration professional requires adobe flash player 10 or above I have Adobe Flash Player 18, and I reset the browser ...
32
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8answers
7k views

How can I stop an intruder plugging into an Ethernet wall socket getting access to the network?

Is MAC address filtering the most suitable option to prevent someone connecting their own device to the network by plugging into Ethernet wall sockets? What if they unplug a device and clone its MAC?
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1answer
554 views

browsing via remote access to my PC with TeamViewer. Can sites track my original IP?

I have a PC connected to the internet with IP#1. I remotely access it to connect to websites from my other PC IP#2 via teamviewer. obviously sites can see IP#1 but is it possible for them to track the ...
1
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0answers
75 views

How to make NMAP command steady and the fastest possible?

I want to make an IP scan using NMAP, but the operating time varies for some reason. The command can be executed in 2 seconds, and if I launch it again just after, it can take 30 seconds. This is the ...
2
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3answers
5k views

How to secure WiFi with user name and password?

We have internet access in both LAN and WLAN in our offices which is only used to internet access. How do we enable a password based authentication in this infrastructure so that authenticated user ...
2
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5answers
329 views

New to Cisco IOS, how can I improve the security of this configuration?

I'm pretty new to IOS and I've been building up a configuration file in Packet Tracer. I still have NAT to setup, as I have to account for a couple of streamers. So, what should I do to configure the ...
2
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1answer
544 views

Do I need to setup NAT or ACL configurations for my DMZ setup?

I'm trying to setup a network configuration in my company like the one in the picture below. A web server publicly accessible in the DMZ but insulated from the internal LAN. For the firewall I'm ...
2
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1answer
74 views

IPsec tunnel with IPv6 and security gateways

Silvia Hagen wrote in one of her books (ISBN:9783952294222, page 463) the following (free translation from german): Tunneling, an essential element of IPsec [...], is problematic for existing ...
1
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1answer
119 views

Opinion on techinique to solve arp poisoning

I have been researching about prevention of ARP spoofing in an individual's device (smart phone or laptop) in a public network. If we save the MAC address of the default gateway at the time of ...
4
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3answers
521 views

How can I know about if there is a smurf attack on my network?

I have been having network issues. The users report to me problems with the internet, but actually the problem is on my network. I have a sonicwall firewall and the device logs indicate posible tcp ...
14
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1answer
45k views

What are the benefits and cons of IGMP snooping?

Our new router is asking if we want IGMP snooping enabled. Not being familiar with this, I looked to the internet and got the following wiki description: IGMP snooping is the process of listening ...
3
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1answer
82 views

Malware lab with watchguard firewall

I have a quick question. This is more of a concept question than an actual problem, but basically what I'm trying to do is set up a malware analysis lab on one of my company's computers. I already ...
2
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2answers
2k views

How can I find which natted private IP address is communicating on Cisco ASA 5508

Normally we are facing abnormal traffic targeting specific servers. My question is How can I know which private IP address is targeted since we are using Dynamic NAT on Cisco ASA 5508 Firewall? ...
3
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2answers
66 views

How are computer networks protected against continous DHCPREQUEST requests?

A DHCP client can send continous DHCPREQUEST requests with a changing MAC address. In a small network it could teoretically cause problems, when a dynamic IP addresses pool is small. How are ...
1
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0answers
41 views

Securing WLAN using one time authentication [closed]

We have a wireless SSID for Managers which I need to secure using one time authentication. Currently we are using MAC filtering but it is insecure. So I am wondering if there is a certificate based ...
1
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1answer
465 views

Multiple DHCP Offers - Which is selected? [closed]

I have created a testing scenario in VMWare for a man in the middle attack using DHCP spoofing. It's for a college project. Windows 8 machine bridged to host adapter Kali linux bridged to host ...
3
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1answer
188 views

dmz and ip-phone on medium network

Hi I'm trying to sketch a computer network. The network include about 50 computers for employees, 20 computers for tech office, a few network printers, a wifi area and every employee has an ipPhone. ...
2
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1answer
2k views

Is a brute force UDP hole punch possible if both external IPs, and both internal ports are known to each client?

So I was just reading about hole punch techniques for UDP and TCP. I read that TCP hole punch can easily be accomplished if a UDP connection has already been established. So here is my theoretical ...
2
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1answer
322 views

How to sandbox internal IPs on the same subnet with one to one NAT

I am curious as to what technologies are employed to accomplish this with vendors that provide this service. What kind of LAN subnet restrictions can be imposed so that 2 hosts on the same internal ...
6
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1answer
3k views

How to view default authentication method for different lines(cty, vty, aux, tty) in IOS?

For example if I enable AAA(aaa new-model) in IOS router with default configuration and try to log in over console line(cty), then there is no authentication. However, if I try to log in over telnet(...
4
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1answer
2k views

Can you only allow local login when TACACS is unavailable on a Juniper?

I'm pretty sure you can do this in the Cisco world, but haven't found a way to do this on a Juniper device. Is there a way to restrict local accounts from being accessed if the router has access to ...
4
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1answer
796 views

IPv6 BGP peering via link-local addresses

I'm planning to run BGP with my upstream provider and advertise our global IPv6 prefixes. I'd like to use only link-local addresses between the ISP's router and my border router to make the border ...
6
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4answers
10k views

Toggle Switch for an Ethernet Cable

Is it possible to place a switch in one of the four/five wires of an Ethernet cable that will disable it? For my hardware project I would like the user to be able to disable the internet connection ...
4
votes
1answer
21k views

How should I diagnose why my Cisco ASA denies traffic?

I have a Cisco ASA, which is denying traffic from 172.16.1.5 to 4.2.2.2 on tcp/9000 How can I diagnose why this is happening from the Cisco ASA CLI?
2
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1answer
46 views

Phone signaling encryption

If we encrypt the signaling between the phones and call manager but not the voice packets, can the call still be intercepted, reassembled and listened to?
1
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1answer
60 views

In case of an intrusion does changing my private ip/lan ip helps?

In case of an intrusion does changing my private ip/lan ip helps ?
2
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1answer
830 views

OSPF with Multiple VLANs

In a Level 3 network with multiple, isolated (i.e. firewalled) VLANs, how does OSPF interact with the VLANs? Specifically: Is it standard to use multiple OSPF instances, i.e. one per VLAN? If the ...
1
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0answers
336 views

wpa-aes EAP-peap authentication problem

I'm trying to connect ubiquity NanoStation M2 as Station/Router mode to a hotspot that I believe has WPA/AES security and EAP-PEAP for auth. I have tested the username and password from my laptop and ...
3
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1answer
175 views

Does violation restrict still apply within same switch but different port

If I have a educational lab that's commonly used for multiple computers for teaching networking. I'm worried that if they remove the computer to put it in the classroom networking gear and come back ...
16
votes
5answers
21k views

Do I need to set the enable secret on Cisco device?

I'm setting up a Cisco 2901 router. I have a login password on the console line, and the vty lines are configured to only accept ssh connections with public key authentication. The auxiliary line is ...
3
votes
1answer
360 views

Per-user network authentication without mac-filtering

I am aware of MAC address filtering available on most wifi access points, but mac filtering doesn't establish a user identity, it only controls access on a device by device basis. One user may have ...
3
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1answer
2k views

How to verify Firewall Session Table or Stateful database entries on Cisco ZBF configured Boxes?

How to verify Firewall Session Table or Stateful database entries on Cisco Zone Based Firewall configured Boxes? what's the command to show the content/records of that table? is there any command like ...
7
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1answer
5k views

Configuring a password policy on Cisco IOS or NX-OS

I was wondering if it's possible at all to configure a password policy which enforces password complexity for locally defined accounts. I know it's possible for TACACS+ and RADIUS, but I need to know ...
0
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1answer
837 views

How does ingress filtering protect against legitimate spoof packets?

I am learning about Ingress Filtering where unauthorised packets are filtered out from entering the network. To get a better understanding of it , I found an article which said: the system ...
3
votes
1answer
1k views

Cisco ASA 8.2(5) same security routing issue

I have an ASA 5510 running 8.2(5) with the following configuration and I am having problems routing traffic between sub-interfaces at the same security level. Although not shown there are ACL's for ...
4
votes
1answer
2k views

IOS-XE: request system shell vulnerability

Catalyst-3650#request system shell Activity within this shell can jeopardize the functioning of the system. Are you sure you want to continue? [y/n] y Challenge: 94d5c01766c7a0a29c8c59fec3ab992[..] ...
3
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1answer
600 views

Spoofed 127.0.0.0/8 possible?

If packets with ip source and/or ip destination 127.0.0.0/8 leaves the node, what can possibly happen? Can this be used as an attack vector against control plane (assuming L2 connectivity)? Scenarios:...
7
votes
2answers
552 views

Switch security when in an unsecured location

I have a situation where I'm required to install a switch in a location that is physically insecure and has guests coming and going. It is in the audio rack of a sound desk at a facility that has lots ...
1
vote
3answers
363 views

Network architecture for a school

I am a computer programmer and having knowledge about networking but not an expert. I have a project in which I have to set up the network infrastructure for a school. The school will have it's own ...
2
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1answer
3k views

Juniper SRX 210: Slow upload performance after enabling UTM IDP

I'm refining a Juniper SRX 210 UTM IDP implementation in a small business. I'm new to Junos, so I'm hoping someone will be able to point me in the best-practices direction. The customer initially ...
3
votes
1answer
319 views

Cisco SG500x-24P - Discard untagged

Cisco SG500X-24P Switch. Goal Only admin tagged frames, discard untagged frames (ingress & egress) Question Is the following configuration correct: Port VLAN Mode: General VLANs: 100T, 200T, ...
2
votes
1answer
372 views

Listen-only (stealth) CDP on IOS

I would like to put my router in a listen-only mode for CDP i.e. it should allow CDP packets to only arrive while not advertising so that I can glimpse into physical topology while remaining hidden to ...
2
votes
1answer
160 views

Best Authentication Practice

We are setting up a new network at work, when the building was comprised mostly of desktops, life was simple -static IPs for everyone. As the company moved to wireless laptops, they began keeping a ...
2
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1answer
237 views

On a wired LAN of 2+ computers, can you securely provide wireless Internet to one and not the others?

I'm a networking noob with three computers (Mac Minis running OS X Mavericks) on a wired LAN (Cisco 5 port fast ethernet switch). IPv4 in the network panel of each computer is configured manually with ...
4
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1answer
1k views

Are users of Captive Portal wifi (web authentication) vulnerable to sniffing?

I understand that connecting to a wireless network using a WEP/WPA key is also encrypting the data you send over the network, hiding it from potential sniffers in range of the network (please correct ...
14
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1answer
2k views

Enterprise Network Equipment vulnerable to heartbleed

On 09/04/2014 the The Heartbleed vulerability was disclosed by the OpenSSL team. The Heartbleed Bug is a serious vulnerability in the popular OpenSSL cryptographic software library. This weakness ...
2
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1answer
561 views

Do routers validate the IP packet length?

Do routers verify the actual IP packet size with that mentioned in the packet?
0
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2answers
1k views

NAT vs PAT Security

i don't know if i have duplicated a questions..but then i still want to ask which one is more risky to be deploy in networking will it be PAT or NAT PAT will make it risky for routing as it will ...
7
votes
2answers
14k views

Securing Cisco device from brute force attacks

I'm trying to block users from configuring a Cisco IOS device if they have entered incorrect passwords a number of times. This is the command I'm using: Router(config)# login block-for 120 attempts 3 ...