Network Engineering Stack Exchange
Network Engineering Stack Exchange

Most Popular

more tags
1500 questions
7
votes
1 answer

Smallest IPv6 block advertised?

We've received a /48 allocation from ARIN, and want to advertise smaller blocks from different sites in our organization. I tried advertising a /56 from each site, but ISP is telling me they won't advertise anything smaller than a /48. So each…
Ron Trunk
  • 66,852
  • 5
  • 65
  • 126
7
votes
9 answers

Is fiber optic Digital or analog? optical signal is digital or analog?

Is fiber optic Digital or analog? optical signal is digital or analog? what kind of signal Fiber generate? I mean traditional phone system is analog, but Ethernet is digital, but what about Fiber Optic? please keep it simple.
mila sarosh
  • 131
  • 1
  • 1
  • 4
7
votes
3 answers

Is IP address Subnet Renumbering needed here?

We have a router with NAT enabled on our edge. The NAT inside is 10.0.0.0/24. Now, we're running out IP blocks and we wish to change this to 10.0.0.0/22. We can do this quickly on the NAT router. But for the host devices, do we need to replace…
Marc_A
  • 123
  • 1
  • 1
  • 5
7
votes
2 answers

Multiple WANs/Out-of-band (Cisco 1900)

I've got a Cisco 1900 router which connects to the Internet using a primary and a secondary WAN connection. When the primary connection is up, all traffic use this link. When the primary connection is down, I use the secondary connection to connect…
Marcus Jansson
  • 81
  • 3
7
votes
3 answers

Is the Nth ports on 127.0.0.1 and 127.0.0.2 same ?

I want to create ssh tunnels between 2 clients and 1 server. Can I use the same port numbers for both but binding one of them to 127.0.0.1:N and the other to 127.0.0.2:N ? Are these ports same or can I use them separately ?
Bünyamin Sarıgül
  • 203
  • 2
  • 7
7
votes
1 answer

Juniper SRX: Where do I look to see IKE debug messages?

Going through a JSEC book I noticed the following slide explains that there are 6 ike phase 1 messages that take place for a tunnel to establish. I am looking in the kmd log and traceoptions data but I do not see any information relating to the IKE…
tunnelsup
  • 828
  • 2
  • 8
  • 15
7
votes
2 answers

ISIS p2p on Ethernet media

I am looking for technical clarity on why someone should / shouldn’t use ISIS p2p topologies on Ethernet media. Ethernet is a broadcast medium , however if it’s configured as a p2p link with /31’s the broadcast domain is minimised , therefore as I…
DrBru
  • 1,609
  • 3
  • 16
  • 32
7
votes
2 answers

Configuring redundancy using floating static

I wanted to post my network layout, but I dont have the required reputation. So I have made up a network diagram below: ISP / \ / \ / \ HQ------Branch | | HQ-PC B-PC What I am trying to do is to…
bob
  • 71
  • 1
  • 3
7
votes
1 answer

Is there a better way to design a Out-of-Band Management Network?

I've been asked to assist in the design of a "OOB" management network, but I have a limited number of resources available. I have the following: 1 Cisco 3750-X stack pair w/ a C3KX-NM-1G network module in each. 8 Cisco 2960-24TC-L "aggregate"…
JDGray
  • 311
  • 3
  • 4
  • 11
7
votes
4 answers

Redirect inbound traffic to another router not running BGP

People, I've two routers on my ISP's core. First of them is a bit old Cisco gear, which is where I have eBGP sessions with my upstreams, IX and downstreams. The second is a MikroTik CCR, which act as DHCP Server, firewall, etc. for my customers. Due…
Tiago.SR
  • 193
  • 8
7
votes
5 answers

TCP timeout, how long does it last?

I have a question regarding TCP timeout. If we look at this picture http://www.dcs.bbk.ac.uk/~ptw/teaching/IWT/transport-layer/timeout.gif We can see that the timeout starts when the packet loss occur, but how long is the timeout? Is it until the…
BlommaN
  • 95
  • 1
  • 1
  • 4
7
votes
1 answer

TCP Handshake Not Happening

Not sure if this is a good stack exchange site to post this on but here goes nothing, The problem, As you can see from my Wireshark screenshot the TCP handshake is not happening. The remote is sending me the SYN message but I'm not responding to…
anders
  • 195
  • 6
7
votes
3 answers

Cisco 1800 drops link to ADVA

I'm having a problem getting a Cisco 1841 connected to an ADVA WAN box provided by TWTelecom. They've given me instructions to force the fasteternet0/0 100 full duplex on interface 0/0, which I have done. When I boot the cisco, there is link and…
user2015032
  • 71
  • 1
7
votes
5 answers

How to view BGP community attached to prefix in Cisco ASR routers?

Cisco ASR routers use IOS XE software. One can see the received IPv4 unicast prefixes from BGP neighbor before any inbound policies with sh bgp ipv4 unic neigh received routes command. Output of this command is following: Status…
Martin
  • 1,177
  • 6
  • 25
  • 47
7
votes
1 answer

What is the correct mask to use with 224.0.0.0?

What is the best mask to use to allow computers to use the multicast IP address 224.0.0.0? I've only seen IP addresses using the lower 8 bits, in my case I just see 22 and 251. So my firewall uses an entry as follow: -A INPUT -i eth1 -p udp -m udp…
Alexis Wilke
  • 216
  • 1
  • 2
  • 7
1 2 3
…
99 100