Network Engineering Stack Exchange
Network Engineering Stack Exchange

Most Popular

more tags
1500 questions
14
votes
3 answers

How to Monitor Vlan Traffic?

We have migrated to a new ISP who provide us several services (Internet+VoIP+VoD) and have divided each service in one vlan 100,101,102 respectively. Now I'm looking for a solution to monitor each service and measure the bandwidth on each vlan. I…
cgasp
  • 2,008
  • 4
  • 21
  • 37
14
votes
2 answers

Stateful vs Stateless IPv6?

What's the difference here? Are stateful IPv6 entries retained in the DHCPv6 server?
stets
  • 1,010
  • 3
  • 9
  • 17
14
votes
5 answers

In a multi-tenant environment what should be done to make your switchports silent on Cisco and Juniper switches?

For example preventing it from sending arp, stp, etc and to reveal as little as possible about the rest of the network. Example use case would be connecting to a peering exchange.
SimonJGreen
  • 1,675
  • 13
  • 29
14
votes
3 answers

how to block ssh tunneling traffic?

if someone were to set up an ssh tunnel to/from work or home, is there a way to prevent future SSH tunneling traffic? I understand that websense can block traffic, but users who use ssh tunneling can bypass websense or other similar products because…
user1609
  • 385
  • 1
  • 4
  • 10
14
votes
3 answers

BGP signalled MPLS issues

I am having an issue getting a VPLS up using an ME3600x with 15.3(2) and BGP signalling. @yelfathi and @packettalk have pointed me down the correct route but not sure how to resolve it. I have 2 ME3600 switches using RSVP as PE and 2 MX80 routers as…
NetDonkey
  • 141
  • 1
  • 6
14
votes
7 answers

Is a DHCP offer packet a broadcast or unicast?

DHCP OFFER is a layer3 broadcast because the server doesn't know the client's IP, but the server knows the client's MAC address. So why does it send the OFFER as L2 broadcast? If anyone ask me about this - how should I answer? Can I say its layer3…
ashok
  • 605
  • 4
  • 7
  • 14
14
votes
3 answers

What is the meaning of RSSI?

When using mobile 3G routers, you see in the output of the "show cellullar 0 all" command. What is the significance of this value? Is this interpretation the same when talking about 2G or 3G? Ex: 2G connection, RSSI -75 3G connection, RSSI…
Bulki
  • 2,383
  • 7
  • 25
  • 44
14
votes
3 answers

Why we get high fluctuation on bandwidth measurement Cacti graph?

We were on redundancy test of Etherchannel and Routing on our network. During this intervention we made some measurement. Our monitoring tool is Cacti for graph. The equipment monitored is a 4500-X on VSS. Each link is on a different physical…
cgasp
  • 2,008
  • 4
  • 21
  • 37
14
votes
1 answer

BGP "no synchronization" command not showing up in running-config

I noticed in the running config I don't see the no synchronization command under the BGP section. Is this a default command so I won't see it unless I change it? Hardware / software Cisco 1921 c1900-universalk9-mz.SPA.151-4.M5
evolvd
  • 754
  • 2
  • 11
  • 19
14
votes
0 answers

PIM-SM with BSR over SSG5 VPN tunnel

I've created a lab to troubleshoot an issue I'm having with PIM-SM and BSR. There are two sites connected via two Juniper SSG5s (6.3.0r17) with just enough configuration to focus on the problem at hand (configs below). The sending site has an…
user1038451
  • 379
  • 1
  • 2
  • 9
14
votes
2 answers

How NAT / PortForwarding / TCP/IP works?

I recently read an article entitled how NAT works. Some things still remain unclear to me. I would be thankful if someone could explain. Below is the part of the article regarding DynamicNAT that is most confusing: A computer on the stub domain…
user2449761
  • 243
  • 2
  • 5
14
votes
1 answer

Troubleshooting low Metro Ethernet TCP throughput

Background We rented a few layer 2 leased lines, i.e. you have one big pipe at the datacenter and the remote sites have smaller pipes. Inside the layer 2 network you can do whatever you like. Probably they use 802.1ad to give each customer their…
Marki
  • 1,211
  • 2
  • 15
  • 29
14
votes
3 answers

How broadcasting works on different networks?

I was reading DHCP ( RFC 2131 ), I have basic knowledge about Relay Agent and Broadcasting. But for Understanding DHCP in depth, I felt like I have to know Broadcasting and Relay Agent ( RFC 1542 ) in details. But could not find any RFC (RFC919,922…
dillip_beta
  • 449
  • 1
  • 5
  • 13
13
votes
3 answers

Management network. Best practises: big VLAN or routed interfaces

We are going to deploy a campus network with approximately 50 switches (Core, Agg, Access). Some of them will be L2 (20), and others will be L3 (30). We are thinking about how to manage these devices: A big VLAN across all switches. Easy to deploy,…
Эдуард Буремный
  • 831
  • 2
  • 12
  • 16
13
votes
6 answers

Finding Non-Cisco End Device IP Addresses Connected to Cisco Switch

I have Cisco catalyst switch, with many VLANs and address ranges. How do I find IP addresses connected to the switch that are not Cisco devices?
John
  • 812
  • 3
  • 10
  • 25
1 2 3
…
99 100