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10 votes
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How are IPv4 Addresses provided uniquely to domains?

Who mainly provides IP addresses to domains? As in, who commands, "www.google.com, 103.233.38.93 is yours; www.stackexchange.com I will assign 104.16.115.182 to you; etc." Normally IP addresses are ...
Peter Green's user avatar
  • 13.3k
8 votes

Why is DNS an application layer protocol?

Protocols at the Physical, Data-Link, Network, or Transport layers do not use names. Only applications need to use names, so DNS is an application-layer protocol because it allows the application to ...
Ron Maupin's user avatar
  • 99.8k
8 votes
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Why is DNS an application layer protocol?

DNS is a application layer protocol, because DNS query and answer is the application level communications. Application layer only understand the query and answer section in the DNS packet. so ...
abdul_razak's user avatar
7 votes
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What is IP-over-DNS tunnelling?

Ron is right with his comment. IP-over-DNS tunneling (or more common name DNS tunneling) is a kind of attack, that allows to bypass usual network protection and send/receive data over DNS protocol, ...
Fuki's user avatar
  • 344
6 votes

Can I see what happens when I run a DNS query?

As others have already answered, most usually a host sends a recursive query to a nominated resolver, often a local server or router, often belonging to an ISP or Google's well-known (distributed) 8.8....
jonathanjo's user avatar
  • 16.3k
5 votes

Why is DNS an application layer protocol?

I think that DNS is an application layer protocol because if for example i want to create a TCP connection i need the destination ip address in layer 4, Am i correct? IP is a layer 3 protocol. ...
manish ma's user avatar
  • 1,624
5 votes

It's not showing the DNS why it is called reverse IP lookup?

Reverse DNS is a term for looking up the DNS PTR record for an IP address - essentially resolving it 'backwards' to a host name (in contrast to 'forward' resolving a host name to an IP address using ...
Zac67's user avatar
  • 84.8k
5 votes
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What are some high-traffic websites that operate with a global anycast IP address?

A couple of examples are: api.twitter.com one.one.one.one dns.google There are always exceptions however - you'll notice that within China, the IP for say api.twitter.com is different for reasons ...
Benjamin Dale's user avatar
5 votes

What's the meaning of requests in Load-balancer?

That seems to use the term 'request' both for DNS queries and for HTTP requests, which makes it a bit confusing. Most load balancers however are able to balance all kinds of application protocols, ...
Teun Vink's user avatar
  • 17.4k
4 votes

How are packets routed based on IP and how are those routes acquired?

Routers learn about routes in three ways: Directly connected networks Manually configured static routes Dynamically through routing protocols A router, receiving a packet on an interface will look ...
Ron Maupin's user avatar
  • 99.8k
4 votes
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Nameserver availability within single ASN

Multi-ASN in this case is more of a proxy for a high degree of network resilience. The basic idea is that primary and secondary servers should be deployed in such a way that the loss of even multiple ...
rnxrx's user avatar
  • 6,114
4 votes

Can I see what happens when I run a DNS query?

A normal DNS client just queries the (DHCP or statically) assigned DNS servers. Only DNS servers usually query root servers, doing a recursive query. You can use a packet capture of your choice and ...
Zac67's user avatar
  • 84.8k
4 votes
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How do I find the IP of the DNS server that respond for a specific domain name?

The authoritative name server should be in the domain's NS record. In Windows, this can be looked up nslookup -type=ns somedomain.com In Linux, something like dig somedomain.com NS +noall +answer ...
Zac67's user avatar
  • 84.8k
4 votes
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If you have multiple domains pointing to the same IP address, can you see which domain a packet was sent to?

Application-layer protocols such as HTTP generally have this capability. At the network layer, no, you can't tell.
Jeff Wheeler's user avatar
  • 5,478
4 votes
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Why DNS services Like google public DNS and Cloudflare 1.1.1.1 has ipv6 versions?

The plan for IPv6 is to ultimately replace IPv4 in entirety. In the long run, it doesn't make sense to run two full stacks in parallel. Also, some providers serve their clients using IPv4 private ...
Zac67's user avatar
  • 84.8k
4 votes
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What does 'CPE' stand for, and what is it?

CPE usually stands for customer premises equipment - a router or modem that is supplied by a provider. The opposite is central office equipment COE. A CPE ID is used to uniquely identify a customer-...
Zac67's user avatar
  • 84.8k
3 votes
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Router decision making w.r.t web browsers

You're mixing up various layers of the Internet Protocol Suite (or OSI model if you like). Routers do not interact with browers directly. Routers interact with hosts, which have IP addresses. As far ...
Teun Vink's user avatar
  • 17.4k
3 votes
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Host IPv6-only website and allow access to IPv4-only clients

IPv4 and IPv6 are separate protocols. So if you want IPv4 only clients to be able to access your IPv6 only server you will need some kind of gateway/proxy service that can provide an IPv4 address to ...
Peter Green's user avatar
  • 13.3k
3 votes
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Who generates all the DNS requests when I plug my public IP router to the network?

Many (really, really many) bots scan all Internet public IP all time, and try to exploit any weakness found in many way. Specifically, DNS is often used to perform DDOS attack by amplification, see ...
JFL's user avatar
  • 19.7k
3 votes

How WANs work and why it is it bad to run DNS and DHCP on a router?

WAN is a very subjective term. Routers have interfaces. Some types of router interfaces are more likely to be used as or called WAN interfaces. For example, PPP, HDLC, Frame relay, etc. are rarely ...
Ron Maupin's user avatar
  • 99.8k
3 votes

Connecting to remote device via hostname that gets its IP from DHCP

If your DHCP and DNS servers both implement DDNS (that's Dynamic [updates] to DNS, I know ISC's Open Source servers do this, and I'm sure there are several others), you can have the DHCP server update ...
MAP's user avatar
  • 366
3 votes

How do you check glue records if your ISP blocks access to the root servers?

Change your ISP. Blocking access to root DNS servers with "DoS prevention" is not something a serious ISP would practice (unless you live in a country with government regulations in place). ...
NetworkMeister's user avatar
3 votes
Accepted

Why only 13 adresses for the DNS root zone

"Each IPv4 address" meaning "each IPv4 DNS root server entry". The article is quite clear on this. 512 bytes of (minimum) UDP payload divided by 32 bytes equals 16. They left 96 bytes for future ...
Zac67's user avatar
  • 84.8k
3 votes
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How does a DNS response reach a client behind a NAT?

The type of translation you are referring to is a Dynamic PAT. This type of translation is often unidirectional. Which is to say, traffic only flows in the outbound direction. But a more accurate way ...
Eddie's user avatar
  • 15k
3 votes
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Cisco IOS: DNS Servers via DHCP

There are some options the client can request when IOS XE (and vanilla IOS, too) is a DHCP client. I dont' have a Catalyst 9k at hand to test, but some of it might be in there, too This is from a ...
Marc 'netztier' Luethi's user avatar
3 votes

Able to ping Domain internal address on home network, why?

You are pinging to public resolve name. Therefore you are getting reply. You cannot ping directly to internal network. If you are getting reply from unexpected Ip address there will be many reasons. ...
infra's user avatar
  • 3,128
3 votes

How do machines setup a route in a network?

How does my computer and x.x.x.x know how to talk to each other? If I use a human messengers analogy, I would tell a person to go get me a package, and I would give him the address of the location and ...
Ron Maupin's user avatar
  • 99.8k
3 votes

Why do we need DNS?

You can do calculations on IP addresses, not on domain names. This allows you to do subnetting, aggregation, route comparison, and many more things. These functions are needed to do route selection, ...
Teun Vink's user avatar
  • 17.4k
2 votes
Accepted

What is route 66 in the context of DNS?

I believe you are referring to port numbers. TCP and UDP (layer-4 protocols) use addresses, commonly called port numbers. Both TCP and UDP use port 53 for DNS. If you want to know which port numbers ...
Ron Maupin's user avatar
  • 99.8k
2 votes

Copying bytes from Wireshark

TCPReplay can be used to replay UDP traffic from a filtered and exported packet capure. Note that it will not work with multiple TCP streams due to issues with the sequence numbers. You may also be ...
James Shewey's user avatar

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