Questions tagged [ipv4]
For questions about Internet Protocol version 4 (IPv4); as specified in RFC791.
IPv4 Address Space Planning Best Practices
A recent question from Craig Constantine pertained to IPv6, but many people are not on the leading edge with IPv6 yet and are still responsible for new or improved IPv4 deployments. I would like to ...
Finding the IP of a MAC Address
Is there a way to derive the IP of a device from their MAC address on a Cisco device? Assume you are not on a local segment where ping sweeping / arp are possible, instead you are remote and there ...
Circular BGP propagation
This one is a difficult to describe, it's hypothetical because I'm learning about routing and right now I'm focused on BGP. Let's say my ASN is 65000, and I announce 192.0.2.0/24. My peer, AS 65001 ...
UDP Message Length Field and Pseudo Header
I'm learning some tcp/ip basics, and am having trouble understanding the Message Length field in UDP. In my book, it says that the Message Length represents the UDP header and data in octets, and ...
VLAN and subnet relationship
Many have pointed out that a VLAN can hold one or more subnets. If your default gateway for this subnet is on a router or a L3 switch then how could there be more than one default gateway in a VLAN ...
Difference between Subnet and VLAN?
You often hear the terms Subnet and VLAN used interchangeably. With the ubiquitous nature of IP these days, when are the two not considered roughly the same from a high-level, understanding that ...
What is the use of wild card masks vs normal masks
I've always wondered what the use of wild card masks was. When I learned about them in college I wondered what the use was, we saw that you could separate subnets by for instance even and uneven IPs. ...
How can I formulate the communication latency in TCP/IP?
I have difficulty in deriving a mathematical model/equation to estimate the round trip latency between two nodes communicating using TCP/IP. The nodes are exchanging data based on HTTP protocol. In ...
How would a router with /32 WAN subnet mask communicate with the rest of the Internet?
I'm studying networking and one of the most basic things I've been told countless times is that computers can't communicate outside of their own subnet. On the other hand, by looking at some ADSL ...
IP prefixes by state (geolocation) [closed]
I've been given a task of creating several filters to block outside traffic by geolocation. In the list of the places that need to be blocked there are several countries (e.g. China and India) and 5 ...
Why don't iperf, scamper and path MTU discovery packet captures agree on the path's MTU?
Let's do some path MTU discovery between two Debian hosts separated by a Debian router that runs Shorewall-generated iptables rules. Each of the two hosts uses a single Ethernet link while the router ...
Migration from IPv4 to IPv6 strategies
As everyone is aware we are out of IPv4 addresses and soon (if not already) we shall be moving on to IPv6. What are some good strategies and practices to migrate a complete IPv4 network onto IPv6?