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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341 views

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

I currently manage ~600 devices in remote sites. We use a proprietary software to monitor these devices, and currently configure static IPs for every device. This requires us to have knowledge of ...
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1answer
123 views

resolving IP address to FQDN effectively [closed]

We use Netflow to control traffic, when i want to resolve the IP addresses from netflow's outside destinations list, i get local google cache server's IP address, never the web sites that users has ...
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1answer
69 views

Access load-balanced website when DNS lookup is restricted on server [closed]

The scenario is - I need to send push notification to Apple push server hosted at gateway.sandbox.push.apple.com. This Apple server is load balanced and the destination IP address can be anything in ...
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1answer
2k views

pfSense Web UI not showing Dynamic DNS IP address

I'm running pfSense 2.2.6-RELEASE and have configured two DynDNS providers: no-ip.biz and nsupdate.info. (I added the latter since no-ip.biz started nagging that I need to log in every 30 days and ...
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2answers
859 views

Preferred anycast paths for DNS with Quagga BGP

Background and goal Am setting up high availability DNS servers based on Unbound. Both DNS servers has in reality twelve BGP sessions against different routers but to make this easier only one router ...
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2answers
3k views

What is IP-over-DNS tunnelling?

What is IP-over-DNS tunnelling please? I have seen this term used in the context of a captive portal. The idea was to redirect clients to the local web server and to force the DNS (?). It was ...
1
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1answer
45 views

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

Glue servers, apparently appear in the parent of the domain. How can these be queried, when for the last few months ISPs have been blocking access to the nameserver ports due to DoS attacks with ...
4
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1answer
213 views

How are IPv4 Addresses provided uniquely to domains?

this question has been bothering me for sometime and I've yet to receive a clear answer (it bothers me whenever I go to sleep). I would like to receive expert answers on this matter. Who mainly ...
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0answers
72 views

University exercise - How to bridge wireless network [closed]

We are currently working on a university exercise and are stumped when it comes to replicating this network, what we are trying to achieve is wireless clients to obtain DHCP address's from a W2k12r2 ...
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2answers
8k views

SonicWALL TZ 300 DNS Forwarding

Clients set up with static IPs and static DNS entries pointed to my SonicWALL at 192.168.0.1 fail to resolve DNS lookup request. Client DNS -> 192.168.0.1 (DNS look ups fail) Client DNS -> Dynamic (...
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1answer
486 views

Load Balancing System For 2 Servers on Different Datacenters [closed]

I am using Ubuntu 15 and I need to implement simple/effective Load Balancer / Fail Over System as per the below requirements: a. It should balance the load between two different public IPs (two ...
1
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1answer
114 views

Understanding DNS cache poisoning

I try to understand how queries from end-users to the DNS server, can posion the cache of the DNS server. Example : I try to understand how can attackers that may take control over a computer , can ...
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2answers
1k views

What is route 66 in the context of DNS?

There is route53 which in the context of AWS is their DNS service. However, I've heard the term "route66" on different occasions in the context of DNS, but it never made sense to me. I tried ...
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1answer
130 views

Only DNS filter guest wireless network, but not main wireless network running through same port on switch

Ive got a setup where im using 5 x Ubquity UAP AC PROs as wireless access points. The rest of the wired network is connected straight from the smart switch (Netgear GS716T), via a patch panel, to a ...
1
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1answer
6k views

How to configure a DNS & web server and allowing them to serve two different subnets [closed]

I'm new to networking and I'm a little confused so could do with some help. I am currently using Cisco packet tracer and I am trying to configure a fictitious network. Initially I was just trying to ...
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1answer
175 views

Cisco 2851 Router DNS configuration questions [closed]

I'm using a Cisco 2851 Router and configuring through the Cisco Command-Line Interface and I'm trying to block certain https websites. Since I have heard that this router only has support for blocking ...
1
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1answer
61 views

Applying IP of a router in another router as a DNS server [closed]

There are 2 router let it be X and Y. For X I have registered on ddns and got a hostname for the router and applied that for remote management. In Y router I have applied the fixed public IP of router ...
3
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3answers
8k views

Why can't I do a reverse DNS lookup on this IP address? [closed]

I keep noticing that web pages I have open are exchanging messages with third party servers without my permission. This is somewhat annoying, and I would like to find out which pages they are so I ...
0
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1answer
94 views

Access hosted site from behind local network?

I have a Windows server 2012 R2 machine running RRAS and DHCP. It has two ethernet interfaces: one for incoming internet traffic, and one for the local network. This server also forwards various ...
2
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2answers
61 views

Why does host+curl take longer than host alone and curl alone? [closed]

I tried to test the speed of my website, so I used time curl "http://google.com" The result ended with real 0m15.589s user 0m0.012s sys 0m0.000s I tried to see what took so long, so I timed ...
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2answers
52 views

Packets: How are they affected with DNS configurations? [closed]

Sorry if this is a very basic question. I'm trying to learn as much as I can about how packets are sent across the different layers on Protocol Stack. One confusion I have is with DNS protocol. When ...
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2answers
562 views

Why do I capture all DNS queries from everyone in the network when I port forward port 53 to my computer?

I'm seeing some things in Wireshark I can't explain. My setup is as follows: A router with a single global IP doing NAT for the devices behind it. I am also behind it with my computer. I port forward ...
4
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1answer
141 views

Copying bytes from Wireshark

Should it be possible for someone to export the binary payload (say from a UDP packet) captured from Wireshark and later send this stream as a "valid" UDP packet? Longer story: I've captured a DNS ...
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3answers
485 views

What exactly is a domain in context of DNS? [closed]

I am trying to understand the DNS. Say I have a domain named mydomain.com. And let's say that we have the following FQDNs: sub0.mydomain.com sub00.sub0.mydomain.com sub01.sub0.mydomain.com sub000....
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1answer
2k views

Where is dns root server located? [closed]

I have some question regarding DNS root server. Where is it located ? In USA ? In europe ? Which company spends money to maintain dns root server ? What about fail-safety ? If root dns fails where ...
2
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1answer
341 views

Fortigate - Redirecting subdomains only?

I'm trying to figure out a way to have our Fortigate 60C redirect certain subdomains but not block complete access to the domain. E.G. I want to block update.microsoft.com but I don't want microsoft....
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2answers
1k views

Choosing between BGP (AS Number) and Dynamic DNS

I have a client that provides an online API service that requires 100% uptime but has been facing connectivity challenges from ISPs. They started out with one ISP (ISP-A), who of course when there ...
3
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3answers
3k views

DNS Resolution:<Backwards IP Address>.in-addr.arpa [closed]

Can somebody please explain whats going on here? localuser@localhost:~$ host 127.0.0.1 1.0.0.127.in-addr.arpa domain name pointer localhost. What's up with the IP address being resolved ...
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2answers
76 views

StackExchange.com IP from Google DNS doesn't work, BUT IP from Whois Database works

There is a strange issue in my office building. According to Google DNS 8.8.8.8, StackExchange.com and StackOverflow.com IP address is 198.252.206.16. Outside of the building's internet connection, ...
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1answer
611 views

Is NAT loopback the only reason I can't view my own website from within my LAN? [closed]

I am new to this so apologies if this is the wrong place for such a question. I'm testing out a simple "hello world" website hosted at home. As we have not been assigned a static IP address by our ...
4
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3answers
467 views

Cannot access certain web page. Ping succeded traceroute didn't

This is my first question on forums at all. I work as a network support engineer and I have a little issue at work and I would really appreciate advice from you. Cannot access the url www.reach2.org ...
0
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1answer
646 views

internal dns for dmz server? [closed]

I have a windows server that's on the domain which has been put in a DMZ. All traffic from the internal network is allowed into the DMZ, but everything initiated from the DMZ heading in is blocked. I'...
1
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1answer
297 views

Explanation of different parts in DNS message format

I am studying about DNS servers, but have not clear idea about some parts of DNS message which are pointed in following figure: One of the things I am not clear about is Questions. Can there be ...
2
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1answer
2k views

Ping domain name using sourced interface

Problem: I want to be able to ping a domain name, sourcing from a particular interface on a Cisco router. Scenario: I have Router-A, an it has a management address of 1.1.1.1. I can only connect to ...
4
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1answer
691 views

Why do some AAAA records behave strangely on existing A records?

I noticed the following odd behavior with AAAA records when querying existing A records. By base domains I mean domain names without subdomains. So when an A record exist and an AAAA record does not ...
0
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1answer
66 views

Host Can't be Resolved Anymore

We are using an application running on a local server, which is linked to a domain-name via a DMZ in a router. Of course, the link between the ISP IP address and the domain name is established as well....
0
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1answer
78 views

Who will do DNS lookup?

I am reading about computer networks. I saw some simple HTTP socket programs(In c gcc). I saw a strange thins on those programs they are using URL directly without any DNS lookup. How this thing works?...
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1answer
67 views

DNS analytics solutions? [closed]

Something like http://netfee.ustc.edu.cn/dns/ Showing top DNS queries and top clients etc. I am not seeing any open source projects doing exactly the same thing, https://www.nanog.org/meetings/...
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2answers
102 views

bind9 selective failure to resolve with particular default route [closed]

I've been running my own name servers (bind9) for many years in Linux boxes, and I have several in my office served by Verizon FiOS. This morning I discovered that I could no longer resolve anything ...
0
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2answers
67 views

Domain hosting IP address [closed]

Can I have a domain hosted with two different IP addresses? I recently was trying to get my domain hosting company to allocate two different IP addresses to my domain and I was told this was not ...
2
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1answer
2k views

Why does a NS record need a domain name, not an IP address? [closed]

I'm a beginning learner of DNS. Some days ago I built a authoritative name server. Writing zone files, I had wondered why the right side of a NS record is specified not in an IP address but in a ...
0
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1answer
78 views

How does Dynamic DNS know when to update IP address in the Dynamic DNS provider? [closed]

When exactly does a Dynamic DNS client update IP on the Dynamic DNS provider? Is it possible that for some short period of time (after the IP from the ISP has changed) the DNS hostname would not be ...
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2answers
175 views

How to use DDNS with scada systems that does not support domain names [closed]

We have a SCADA system that needed to pool stations via fixed IP addresses. Our station does not assign fixed IP, so we would like to use DDNS to resolve this issue. However the SCADA system does not ...
1
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1answer
880 views

DNS: retry and TTL values [closed]

I read some explanations on the Internet on the topic and also BIND and DNS 4th Edition chapters 4.2 (Setting Up Zone Data) and 8.4 (Changing TTLs). Still I have some doubts. A brief refresh first of ...
2
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1answer
409 views

Serve a different server IP to clients based on locations

I am looking for a way to server clients a different IP based on location. I'm a Casper administrator (Mac management using software by JAMF Software) and manage over 75 distribution servers globally....
2
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1answer
689 views

DF bit always set for DNS query response

When I tried packet capture with wireshark, I observed that the Don't fragment bit is always set for 1. all TCP packets and 2. DNS query response. I understood why it is so in case 1, here Now, my ...
3
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2answers
248 views

Is Reverse DNS part of the DNS protocol? [closed]

Is reverse DNS part of the DNS protocol, i.e. part of the official DNS specification? Is reverse DNS managed by standard DNS servers and a type of request that DNS servers understand and respond to, ...
1
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1answer
5k views

Configure DNS Table on Sonic Wall TZ205

I just installed a TZ-205 on our company network and I can not seem to find where I would add to a DNS table. On our Linksys LRT224 there is a option to add a domain name and an associated IP. Does ...
4
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2answers
785 views

DNS/domain not working on cisco pix 515e

I was able to pick up a pix515e for my home network, I've got it running Version 8.0(4)28 and Device manager version 6.1(3) which I think are the latest that it will support with its 64Ram/16Flash. ...
2
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1answer
10k views

Why does my router not reply to ARP requests? [closed]

I am trying to test the ability for an embedded system to create DNS requests and process their replies, but I'm having problems getting those replies. Physically, my embedded system (192.168.1.50) ...