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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8 views

How are nameservers selected by hosts? [closed]

When I access my gateway's web interface, there are two sections for primary and secondary DNS servers. It is my understanding that these were selected by (and probably belong to) my ISP. My question ...
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11 views

Can't connect VM's brouser to Internet in GNS3 [closed]

I have a problem with connection Windows VM to internet in GNS3 I've configured nat and dhcp on cisco router. VM can ping 8.8.8.8, but can't "ping google.com". Dns on router is enabled, and router ...
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8 views

Use MX records to forward all mail to specific server [closed]

I have two domains, lets call them example.com and example.de I need to have all emails sent to an (any) example.de address being forwarded to the example.com email server. Is it enough to place an ...
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13 views

Making our DNS resolving / recursion more resilient and more private [closed]

We want to make our DNS resolving more resilient, independent and less susceptible to spying by tech giants/ISPs by setting up our own DNS recursor. The DNS infrastructure is known to be one of the ...
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0answers
25 views

what enables cloudflare to disable direct ip access? [closed]

When I visit a website that has Cloudflare, using the website's ip address, I get this message: Error 1003 Direct IP access not allowed What happened? You've requested an IP address that is part ...
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1answer
63 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 ...
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1answer
52 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-...
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2answers
68 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 ...
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1answer
209 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 ...
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1answer
83 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 ...
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1answer
55 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 ...
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1answer
34 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 ...
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1answer
60 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 ...
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3answers
48 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 ...
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0answers
395 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 ...
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0answers
198 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 ...
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1answer
160 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 ...
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3answers
762 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 ...
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1answer
49 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....
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1answer
60 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 ...
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1answer
88 views

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

I have searched a lot but I didn't get the reason that even after giving the IP address it never shows the DNS. If it doesn't give the DNS then why it is said to be reverse IP lookup?
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1answer
283 views

Access internal webserver with domainname points to external IP

We have a webserver on our LAN. Externally, we can use the public domainname (let's say business.com) to access the website. Internally, we need to use the local IP. We also want to use the public ...
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140 views

Different DNS resolution for same domain name [closed]

I am getting different DNS resolution for www.google.com. When I am using Google Public DNS i.e 8.8.8.8 then by using nslookup then it is giving IP address of Non-authoritative answer: Name: www....
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1answer
433 views

Can I ping a specific site without DNS server information? [closed]

If I clear DNS cache and remove DNS server information, how can I ping to a specific site?
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2answers
2k views

How to force users on my LAN to use a specific DNS server using ARP poisoning?

I'm attempting to force all hosts on my LAN to use a specific DNS server to filter certain material, however I'm running into problems. I've had problems in the past trying to configure my router's ...
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1answer
33 views

TZ205W DNS Issue

I have a firewall that is setup but need to have all users inside the network to use a preset dns server. While I know that I can set up this in the DHCP it does not stop a user from changing it in ...
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2answers
81 views

How can a public DNS server know the hostname of a machine on a private network [closed]

Example: a home LAN a simple SOHO router (both DHCP and DNS server at 192.168.1.1) 2 client machines (192.168.1.2 and 192.168.1.3) Is it possible for the Google public DNS server located at 8.8.8.8 (...
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1answer
84 views

Iterative queries of a default DNS server

I have just started to study networks and I have a confusion about what happens when a default DNS server does iterative queries to other DNS servers to resolve a name in an IP address. I am very ...
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3answers
243 views

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

My understanding is that when my computer wants to resolve a host name, it will ask the DHCP-assigned DNS servers first. If those don’t know, it goes and asks the ‘root servers’ who then defer to ...
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1answer
50 views

SRV Record for Service X [closed]

I've got a quite common question, which I can't find an answer for. Is it possible to create a SRV Record for any possible service I'm running? For example: I want webinterface.example.com to ...
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1answer
36 views

Is it possible to convert a public IP and port to a DNS? [closed]

Must be said, I'm a complete ignorant on these matters. Is there a way or service so I can take and IP address and its port and make it a DNS? Is it possible or am I doomed?. Thank you.
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1answer
65 views

WHOIS request with nodejs package failing [closed]

I'm trying to do a bulk whois lookup of around 7000 domains. I use the node js package whois. This worked while I tested with individual domains. After I made a bulk request for batch of 50 domins, ...
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1answer
172 views

rate-limit dns queries on HP procurve 8212zl

I had ast week the situation that a user accidentally got our DNS server to its knees by sending over 270K DNS queries to our dnsmasq. I was looking for a reliable method to prevent this Happening in ...
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1answer
502 views

Tracert getting timeout on second packet consistenly

I'm on a vpn and tracing to virtualmachines that live in the VPN Server. I've been experiencing slow queries, when they should be fast. below is what the trace is returning. I'm curious as to why the ...
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0answers
24 views

Should static IPs be set on the DNS/DHCP server, the host, or both? [closed]

Assuming a pretty regular business setup, when assigning static IPs for servers to use, should they be assigned on the DNS/DHCP server? Should they be configured individually on the hosts? Or should ...
3
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1answer
300 views

ASA as a local DNS resolver

I have an site to site VPN access configured by ASAs. My remote site needs to connect to the domain through the tunnel which will required DNS located on the main site. I would like to use DNS server ...
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3answers
6k views

Why is DNS an application layer protocol?

The main role of DNS is to translate Domain Names to their corresponding IP adresses, so why is necessary to be an application layer protocol? I think that DNS is an application layer protocol ...
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1answer
986 views

2 different servers listening to same port and same public IP [closed]

I am running 2 VMs that they both are listening to ports 80/443. I have just one public IP and several subdomains that are pointing to my public IP. I would like to somehow be able to access both VMs ...
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2answers
5k views

fortigate 50e conditional forwarding

my first post here, any help is appreciated. I have a fortigate 50E with a bunch of PCs connected to it which form my internal network. One of the PCs is running a web app (Confluence to be precise). ...
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1answer
167 views

Juniper SSG Split DNS not working over tunnel

I am trying to get the DNS Proxy feature working in an SSG5 (Side B). The other side of the VPN is an SSG140 (Side A). The DNS server is on Side A. foo.com should send DNS queries to 192.168.1.2 (...
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1answer
286 views

Why only 13 adresses for the DNS root zone [closed]

I know about anycasting and I know about the UDP limitation. Now, I was reading this article and it says the following (emphasis mine): Each IPv4 address requires 32 bytes. Accordingly, the ...
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1answer
134 views

Nameserver availability within single ASN [closed]

I've heard someone say today that a highly available domain name should be configured using nameservers located in different ASNs. I've however taken a look at the namesservers for google.com and all ...
0
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1answer
110 views

Can't resolve hosts after adding manually setup DNS servers on windows machine [closed]

I have setup as shown in this picture. I configured a bind9 dns server on ubuntu (192.168.242.11) When I set this as the DNS server for the Test Machine, it can resolve hosts perfectly well. When I ...
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1answer
41 views

Find IP's owner instead of carrier [closed]

I have a list of IP addresses and I want to find out their owner. In many cases dig returns the name of their carrier for example AT&T. Is there a way to overcome this and find the company at ...
3
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1answer
381 views

Who generates all the DNS requests when I plug my public IP router to the network?

When I plug my router with a public IP address on it into the network, I get discovered after few hours to days and become 'flooded' with DNS requests from many sources. Who generates these requests? ...
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1answer
1k views

External DNS intermittent issue on anyconnect remote vpn

I have a anyconnect remote vpn profile where I am having the problem with intermittent issue with external dns. I can not open any external weblink and cant ping it with name but accessing them with ...
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1answer
2k views

DNS Caching Server on Cisco Router - How to set Forwarder timeout and retries?

I have configured a Cisco 1921 router to act as a DNS Caching Server by using the following configuration snippet: ip dns view default ip dns server ip domain retry 1 ip domain timeout 1 ip domain ...
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1answer
366 views

Per VLAN DNS Host Override Using Same Name

Is there a way to setup PFSense so that each VLAN get's a different DNS Host Override for the same domain. As in, if I have 2 VLAN's and a client on each one goes to internalsite.com, it will ...
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1answer
45 views

Router decision making w.r.t web browsers

Two different websites have been opened from two different browsers(for instance chrome and firefox) on the same IP Device(PC) connected to the same router. When the response comes from far end, it's ...
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2answers
3k views

Host IPv6-only website and allow access to IPv4-only clients

Lets say site.example.com runs only with AAAA records, and I wish to access that site from IPv4-only network, and I don't want to do tunneling neither other protocols that masquerades IPv4 over IPv6 ...