Questions tagged [dns]

This tag should only be used when it's about configuration of DNS on an on topic network device. Any general DNS service related questions are off topic.

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ERR_ADDRESS_UNREACHABLE error intermittently [closed]

I have a website (greatsistema.com) for internal company use that we use from several locations. Intermittently at 1-2 branches (different locations) the site goes down with a ...
Silver Lora's user avatar
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1 answer
134 views

Is DNS address included in ARP address table?

I have DNS server address 8.8.8.8 . Is it supposed to be included in my ARP table when i execute arp -a?
Χρίστος Κουστένης's user avatar
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1 answer
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How to prevent a user from using YouTube while connected to my network [closed]

i need to restrick specific user from using youtube and other socialmedia during job time
Kapala's user avatar
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1 answer
397 views

Why does pfSense require a DNS access list entry when all interfaces are selected?

Netgate 4100 v23.05-RELEASE The DNS Resolver was only working on LAN 1 but not LAN 3 (physical nics, not vlans). I added an access list rule as suggested here to grant LAN 3 access and now ...
user2864874's user avatar
1 vote
1 answer
322 views

DDNS for Palo Alto Behind NAT Internet

We would like to configure SDWAN for our branch site that only has broadband internet. In order to do that we need to know from which public IP does the PAN use to initiate the SDWAN. Because the ...
Eternity Neet's user avatar
1 vote
1 answer
498 views

What does 'CPE' stand for, and what is it?

In reading up on NextDNS, I came across the add-cpe-id option to dnsmasq: --add-cpe-id= Add an arbitrary identifying string to DNS queries which are forwarded upstream. NextDNS uses this for your '...
OJFord's user avatar
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3 answers
132 views

DNS Servers and Host Names

I was studying how to set up DNS on a Cisco router, and I got confused on this piece that stated: "Next step is to configure your DNS server with the host names of your local network, this way ...
Gyd-4nc3's user avatar
1 vote
1 answer
38 views

How does a Root or Authorative DNS server reply to the correct Anycast server? [closed]

Let us say there are 2 recursive Anycast DNS servers, A and B, with IP 200.0.0.0. A needs to look up 'example.com' and queries Root server C. However, in the routing table of the BGP router where C is ...
Akitirija's user avatar
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1 answer
139 views

Using an internal domain name across a site-to-site VPN [closed]

I've searched around and can't quite find an answer to how I can share a domain name between a site-to-site VPN. Here is a rough sketch of my network: Is it possible to have mulquin.net as the local ...
Jacob Mulquin's user avatar
2 votes
2 answers
109 views

How ARP works [Specific Case]?

After reading about ARP and NAT I'm really confused about putting them to work together. Let's suppose we have a router A with a public IP of IP(A). Plus, 2 devices behind that router B and C, each ...
Ori's user avatar
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1 vote
1 answer
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Why do we need DNS? [closed]

The case for DNS usually goes like this: People like names. Computers like numbers. So we let people use domain names and use DSN to convert them to IP numbers and everybody is happy. But IP numbers, ...
sourcream's user avatar
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1 answer
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where is the local resolver? [closed]

I'm looking into dns cache poisoning and I was confused as to where the local resolver was located. From what I understand the local resolver is located in a DNS server where we perform lookups when ...
a_confused_student's user avatar
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3 answers
937 views

What if I run tracert command while there is no connection to the DNS server?

What happens if I run the tracert x.x.x.x command while there is no connection to the DNS server?
Denys_newbie's user avatar
1 vote
1 answer
171 views

Configure AAA on a router - Extended ACLs

How do I write a named extended ACL which will allow for traffic between a DNS from a LAN (IP address) to a DNS server at (IP address), ping from a host PC (IP address) to any destination and allow ...
maggiejmyers1973's user avatar
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1 answer
48 views

How to force routing to https website without the IP

I am attempting to limit a group of Chromebooks to access one particular site for student testing. The issue is that the website is secure but the ssl cert is attached to the url not the ip. The ip of ...
Dorman D Kehr's user avatar
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2 answers
130 views

Do domains frequently change their IP addresses

I have the domain of some organization that requests my site too much. I want to restrict their access - but how? We only have the domain of the requester sfasu.edu . The QA of our team is using tool ...
Hairi's user avatar
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0 answers
196 views

Cisco DHCP using dynamic updates

I would like to use a configuration on a Cisco router that allows for clients to resolve the names of other clients without the use of mDNS. I have following configuration: roTST01#show running-config ...
Mario Jost's user avatar
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2 answers
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Packet Tracer - PING from CLI of router to website

I am currently sending a PING from a Router2 of the Network shown bellow. By using the CLI commands I'm trying to do it in 2 different ways: PING + IP 192.168.1.9. As a result, it succeeds. PING + ...
icatalan's user avatar
1 vote
2 answers
125 views

How do machines setup a route in a network?

So I have been reading a bit about networking, and I am a bit confused about what exactly happens after domain name resolutions. Lets say I do a get request to "some.website.com". First, my ...
EHM's user avatar
  • 113
-1 votes
1 answer
236 views

Why can't I access Whitehouse.Gov with the IP address or the Aliases? [closed]

I'm studying the basics of networking at the moment, and I was testing out what I had learned when I discovered that I could not access WhiteHouse.gov via the IP address. After using dig on WhiteHouse....
Guy4444's user avatar
0 votes
1 answer
28 views

What is the significance of configure TTL value while creating A record and AAAA Record in External DNS [closed]

Is Time to live (TTL) value has any impact on DNS querry . Because in our external DNS we generally set TTL value to 1 hours and some times 5 minutes while creating A records and AAAA records in ...
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1 answer
284 views

Why DNS services Like google public DNS and Cloudflare 1.1.1.1 has ipv6 versions?

I understand the need for ipv6 as we ran out of ipv4 but dns resolvers like google and cloudflare already have ipv4 addresses for resolving dns and i don't see compatibility as a reason either because ...
Pooya Estakhri's user avatar
0 votes
1 answer
2k views

How is traceroute able to display hostnames?

When performing a traceroute, what function on the ISP gateway is advertising the hostname? When we traceroute to Google.com for instance; Tracing route to google.com [216.58.213.14] over a maximum of ...
Graham Warrender's user avatar
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2 answers
44 views

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

When I read thisarticle: there is a term: Load-balancer is the piece of hardware that listens on a particular IP address and forwards the requests to other servers. Major sites will typically use ...
26334_zeal's user avatar
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1 answer
46 views

DNS request on google.com. with QTYPE = 0xff returns no entries [closed]

Ive written my own DNS request client but I'm having some interesting behavior. If I send the request with the QTYPE section = 0xff, I get a valid response however with no entries. My Request: 0x70 ...
SwimMaster's user avatar
0 votes
1 answer
187 views

How do I know when an AAAA record is required? [closed]

I'm trying to wrap my head around DNS. My biggest issue right now is understanding when an AAAA record is required. Recently, I was asked by a colleague to point a subdomain from Server A to Server B....
abcdef's user avatar
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0 votes
1 answer
22 views

Will DNS TTL impact Browser’s HTTP Cache? [closed]

Browsers are known to cache HTTP resources to save bandwidth and improve performance. I’m not 100% sure about how HTTP cache works in web browsers but I can see sometimes that an object with “cache-...
wgq23ggee's user avatar
  • 211
0 votes
1 answer
326 views

What is the purpose of Cisco's `ip domain round-robin` feature?

While configuring one of Cisco's routers and reading documentation I've found an interesting feature: ip domain round-robin. Documentation says, that this options makes dns server rotate entries ...
PF4Public's user avatar
  • 103
0 votes
2 answers
1k views

Can Cisco Config cause Unidentified Network

I have a Cisco C9300-24P layer 2 switch with a dozen computers and 2 servers on the same VLAN, all statically set with no default gateway as there is no router and all offline from the internet. The ...
JukEboX's user avatar
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0 votes
2 answers
60 views

If you have multiple domains pointing to the same IP address, can you see which domain a packet was sent to? [closed]

If you have multiple domains pointing to the same IP address, can you see which domain a packet was sent to?
Simon Shkolnik's user avatar
0 votes
2 answers
228 views

Best way to make a network failsafe?

I have a Debian based machine with 2 completely different network interfaces from 2 different ISPs acting as a backup for my server connection. These have two different IPs (Let's say IP1 and ...
roee klinger's user avatar
0 votes
2 answers
2k views

Why can i ping domain from Pfsense diagnostics but not from my desktop?

I'm setting up Pfsense to replace our existing firewall with. Currently the setup is pretty straight forward. I have internet connected to my wan port connected a switch to the lan port connected ...
CodeNinja's user avatar
  • 219
1 vote
0 answers
249 views

If a server has both IPv4 and IPv6 addresses, how does the DNS determine which to return? See the following example [closed]

These Pings were done at different times of the same day: C:\Users\LPress>ping www.ucla.edu Pinging gateway.lb.it.ucla.edu [164.67.228.152] with 32 bytes of data: C:\Users\LPress>ping www.ucla.edu ...
Larry Press's user avatar
0 votes
2 answers
70 views

How can I use 1 static public IP address for multiple private networks in totally different physcical locations?

So, I know that DNS is important in the running of CDN services. DNS allows the routing client traffic to the physically nearest CDN server. Question is, how can I do the same thing without any DNS ...
lpydawa's user avatar
  • 265
-1 votes
1 answer
253 views

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

I have a strange issue, I am able to ping my company's internal address (ex: hq.mycomapny.com) when I am on my Home network (WI-FI or Enthernet) and NOT connected to the VPN. When I do a ping on the ...
as134_user3693277's user avatar
2 votes
1 answer
1k views

Cisco IOS: DNS Servers via DHCP

Simple question: I have following switch configuration: interface Vlan1 ip address dhcp end ip domain-lookup I receive and IP and DNS servers along with it from our DHCP server. At least Windows ...
Mario Jost's user avatar
  • 1,709
-1 votes
1 answer
102 views

What special reserved domain could I use for virtual organization private network? [closed]

Suppose we have a inner-facing network that spans several geographical jurisdiction - this network can only accessed from our offices with special HSM installed, and we want to enable domain-name-...
DannyNiu's user avatar
  • 173
2 votes
2 answers
178 views

What are some high-traffic websites that operate with a global anycast IP address?

I've been trying to find an example of an anycast IP address used by a hugely popular service or a website. According to my queries at https://www.whatsmydns.net/ , none of the large sites that are ...
ahmet alp balkan's user avatar
1 vote
1 answer
1k views

DNS expire-entry-timer has negative affect on ASA using FQDN ACL

I have a Cisco ASA using FQDN egress ACLs for a host that changes IP addresses every 10 mins (Apple APNS IP address pool). As soon as the TTL expires for the addresses, my internal server requests a ...
Pobbel's user avatar
  • 11
0 votes
1 answer
380 views

LAN to WAN IPv4 address mapped to LAN server through NAT Rules or other

I need to set a rule that allows me to connect BOTH from OUTSIDE the LAN (from the "internet" to the Internal server at IPv4 address 10.64.0.50 via port 22, by running ssh://1.2.3.4 -p 22; AND From ...
Digiman Brunnell's user avatar
2 votes
1 answer
1k views

How does a DNS response reach a client behind a NAT?

How does a DNS response reach a client behind a NAT? I'm talking about DNS queries using UDP for transport with a server that is not in the same network as the client. Does the NAT correlate the ...
Philippe's user avatar
  • 125
1 vote
1 answer
48 views

Why does www DNS record propagate faster than @? [closed]

I've recently had to move a DNS ownership from one DigitalOcean account to another. During this process I've noticed that the www A DNS record propagates a lot faster than the @ A DNS record. Why ...
personjerry's user avatar
0 votes
1 answer
208 views

Dynamic DNS and VPN [closed]

I have a few PCs/services that I want to access remotely, which are inside a VPN and gets assigned local IP addresses using DHCP. How can I setup dynamic DNS to access the PCs on their internal VPN ...
Sonja Brits's user avatar
-1 votes
3 answers
902 views

ACL for DNS clarification

I do not understand why the second ACL is needed if all I want is to ensure all networks use a certain DNS server (for example 192.0.2.1) access-list 112 permit udp any host 192.0.2.1 eq domain ...
Novice Programmer's user avatar
1 vote
0 answers
861 views

DNS not resolving through VPN [closed]

Looking for some help with our Office's VPN that I can't seem to solve... I am trying to remote desktop to the Work PC from Home PC via the DC ASA 5506-x VPN. I can only connect to the Work PC with ...
Jeff's user avatar
  • 11
1 vote
0 answers
537 views

Cisco IP SLA HTTP request with frontdoor VRF

I am trying to use a IP SLA for HTTP on my Cisco ISR 4321 router to check if a website is reachable. The challenge is that I need to do that in a frontdoor VRF. I have configured ip name-server vrf ...
Daniel's user avatar
  • 1,071
0 votes
1 answer
2k views

How is a lost DNS query handled [closed]

If a DNS query gets lost along the way to its destination, is nothing done about it? In my networking class, my lecturer said that DNS runs on UDP. I verified this in Wireshark by doing nslookup for a ...
Kuni_Leqa's user avatar
2 votes
4 answers
3k views

connect a cisco router to the internet through a cable modem

The router gets an External IP address via DHCP from the Cable modem Clients inside the network get an IP address from Router's DHCP server I can ping that the external IP address from a client inside ...
Dario's user avatar
  • 21
1 vote
1 answer
97 views

How do I find the IP of the DNS server that respond for a specific domain name?

So as the title says I want to get the IP of the DNS server that respond when I'm trying to reach a specific domain, using bash commands. If I understood it right, when I'm trying to reach www....
Zest's user avatar
  • 13
1 vote
1 answer
88 views

Quanta switch not resolving addresses

I've got this brand new Quanta T3048. I've configured the VLANs we need but it came to my attention that the switch won't resolve any address even though I've set it (according to the configuration ...
excessive's user avatar
  • 117