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Questions tagged [dns]

The Domain Name System (DNS) translates Internet domain and host names to IP addresses.

138
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3answers
26k views

Did I just get DNS Hijacked?

I went online on my Macbook today and noticed my iTunes complaining that it couldn't connect to Apple, I tried logging out and in of my account but weirdly it said it couldn't log in; I didn't think ...
69
votes
5answers
14k views

What makes Let's Encrypt secure?

Let's Encrypt is an initiative from the Electronic Frontier Foundation (EFF), Mozilla, Cisco, Akamai, IdenTrust, and researchers at the University of Michigan that aims to automatically provide every ...
54
votes
3answers
13k views

Is my Windows 10 machine experiencing DNS poisoning? I keep getting Chinese IP addresses when connecting to a U.S. government domain

I've found that some .gov sites are being redirected to a Chinese IP. I have searched across Internet to see if this a known form of malware but I'm unable to find any info. I would like someone ...
53
votes
6answers
8k views

Why don't browser DNS caches mitigate DDOS attacks on DNS providers?

Why are the recent DDoS attack against DNS provider Dyn, and other similar attacks successful? Sure a DDoS attack can bring an entity down, and if that entity controls DNS servers then queries to ...
51
votes
5answers
44k views

How do I run proper HTTPS on an Internal Network?

This question has been asked several times, I'll link a few: https://superuser.com/questions/791015/https-over-private-network https://stackoverflow.com/questions/616055/https-certificate-for-...
38
votes
4answers
7k views

How could a public DNS server return bad results?

I live in a country which is under many sanctions. Both internal sanctions (government on people) and external sanctions (US on our people). In our country, YouTube, Twitter, Facebook and many other ...
37
votes
4answers
16k views

How can changing your DNS protect your online privacy?

Looking at a Unblock-US Features (a DNS provider) on their website it states the following: Stay out of the radar of prying eyes. With Unblock-us, you’ll have peace of mind knowing that your ...
36
votes
5answers
155k views

If I use a VPN, who will resolve my DNS requests?

Will they be resolved by my VPN provider, or by my original ISP (if left on "automatic" settings)? Would I have to manually configure a dns server, to make sure my requests will not be resolved by my ...
35
votes
8answers
45k views

How can I find subdomains of a site?

One of the things I need to do from time to time is to find subdomains of a site for example. Starting with example.com sub1.example.com other.example.com another.example.com I'm ...
30
votes
9answers
9k views

Can a HTTPS connection be compromised because of a rogue DNS server

If I'm visiting (just a desktop PC, client side) a site that has a valid HTTPS cert/connection, that can it be compromised if I'm using a rogue DNS server (not deliberately, I'm concerned about an ...
27
votes
2answers
63k views

DNS zone transfer attack

Can anyone explain what is DNS zone transfer attack or give any link, paper? I have already googled, but could not find anything meaningful.
27
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1answer
4k views

Why is it better to use ports 20 and 53 as source ports when portscanning?

I read that if a server is inside a DMZ behind a stateless firewall, it is a good idea to use ports 20 and 53 as source ports when conducting port scanning. Why is this a good idea? I guess the ...
25
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3answers
1k views

What are some risks of purchasing a “used” domain name

If you purchase an existing domain name that was already used by someone else what are the ways in which the domain could have been broken by the previous owner? Are such problems common and are there ...
25
votes
2answers
4k views

How does a website know the DNS server a client uses?

There are websites which claim to do "DNS leak tests". I don't care so much about DNS leaks but am curious, how does the website know which DNS server I am using? I guessed it would be a header sent ...
24
votes
2answers
7k views

How does DNSSec work? Are there known limitations or issues?

Based on information from this site, DNSSec is needed to protect us from a number of DNS and SSL / TLS hacks, including: DNS spoofing, especially on wifi or shared medium Registrars that abuse their ...
23
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6answers
5k views

Why do DDoS attacks cost a fortune to stop?

I have read so many stories that a major DDoS attack is causing companies thousands of dollars to mitigate. I have two questions: Is this because they try to keep the servers accessible to real site ...
22
votes
5answers
7k views

How secure is binding to localhost in order to prevent remote connections?

Let's say we're running a service that's bound to localhost (127.0.0.1), and the goal is to only allow local clients (i.e. from the same machine only) What techniques might be used to break this ...
21
votes
5answers
14k views

Do you detect/react to DNS tunnelling?

I've just seen a talk about tunnelling TCP/IP over DNS requests, because port 53 UDP is usually open and unfiltered. What techniques exist to detect and block such tunnels, and have you ever seen that ...
20
votes
4answers
7k views

What stops someone from just redirecting a HTTPS connection to a HTTP version of the site?

Let's say someone does an ARP spoofing or DNS poisoning attack to redirect traffic to their own web server. If the real site has an SSL/TLS certificate, would that stop the hacker from redirecting let'...
19
votes
5answers
6k views

Does DNS allow third parties to register subdomains?

I have one of those questions that rely on the rule sets for DNS lookup. Let us say Person A owns the site https://www.example.com. A different person, Person B, not associated with A, attempts to ...
18
votes
4answers
809 views

Global Blackout is a myth?

In order to shut the Internet down, anonymous claimed that putting-down the 13 root DNS servers of the Internet and therefore disabling the HTTP Internet, the most widely used function of the Web, ...
18
votes
3answers
10k views

DNS Amplification DDOS attack

During the weekend I made some tests to simulate an DNS Amplification DDOS attack. sending about 90Mb/s traffic I was able to generate about x.x Gb/s amplified traffic which sent our datacenter ...
18
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7answers
3k views

Can I trust DNS servers?

If I use my own VPN and use third party DNS - can I trust it? For example, is there any possibilities that an attacker can track the requests by contacting the DNS-hosting (assume that attacker have ...
18
votes
4answers
5k views

Does Tor Hidden Service Protocol provide more threat protection than a standard HTTPS session?

DuckDuckGo is a search engine that has a Tor Exit Enclave and hidden service. This site is focused on the safe, secure searching of its users. Since DNS is not used in Tor, it appears that HTTPS is ...
17
votes
7answers
2k views

Would it be possible to overload a large part of the internet, and if so then how?

Last week a news article went viral about a Dutch web hosting/data center company that was allegedly using a DNS amplification attack to DDoS an anti-spam company, because they blacklisting the former....
17
votes
1answer
1k views

Why don't browsers check CAA records to help ensure a certificate is valid?

If I understand correctly, Certification Authority Authorization DNS records are used to specify which certificate authorities are allowed to issue certificates for a given domain. If that record ...
17
votes
4answers
8k views

DNSSec (Comcast) vs DNSCurve (OpenDNS)

I was previously using OpenDNS on my internal network. I found out today that Comcast has switched over to DNSSec: Comcast DNSSec. I've done a little research on DNSSec and its benefits. I ...
17
votes
4answers
57k views

Pros/cons of using a private DNS vs. a public DNS

I was wondering why a company should use a private DNS. In comparison with a public DNS, which advantages does a private one have, and which issues can a public DNS create for a company? I'm new at ...
16
votes
3answers
11k views

How can someone sinkhole domains?

The Wikipedia article about CryptoLocker says: In late-October 2013, security vendor Kaspersky Labs reported that with the help of a researcher, it had created a DNS sinkhole to block some of the ...
16
votes
2answers
27k views

Is there any disadvantage in using OpenNIC for DNS resolution?

What are the advantages/disadvantages of OpenNIC vs ISP for DNS resolution with regards to security and privacy?
16
votes
1answer
1k views

Do any DNS registrars support multi factor authentication?

I am looking for a DNS registrar that supports strong multi-factor authentication. Does any DNS registrar support multi-factor? Is this a legitimate need?
15
votes
5answers
4k views

Can I avoid DNS spoofing by typing the IP address?

The question is in the title. I have been reading about DNS spoofing. What if I were to save the IP addresses of websites I consider sensitive and then just enter the IP address when I am using a ...
15
votes
3answers
2k views

External websites in logs [duplicate]

I have a website, let's call it www.good.com. I've been getting a lot of requests to www.good.com under completely different URLs than www.good.com. I suspect this traffic is also causing some site ...
15
votes
2answers
5k views

How bad is the leaking of Internal IP addresses through external DNS

If an external DNS server is leaking internal IP addresses are there any significant security threats associated with this information leakage? Apart from most the obvious - gaining an understanding ...
14
votes
2answers
3k views

How can I stop someone from displaying my website on his domain?

I just discovered that someone is pointing their domain name to the server I use for a website, which results in traffic to their domain displaying the content of my website. How can I stop this ...
14
votes
3answers
1k views

Why is RFC4255 (SSHFP) not used for https?

I had this idea a few hours ago, but of course it already exists and there is even an RFC... Why don't we publish the fingerprint for the SSL/TLS certificate via DNS? We need DNSSEC to make sure the ...
14
votes
1answer
3k views

Is my modem compromised?

My modem automatically changes its DNS server from Norton DNS server to AdClick server. How do I prevent this from happen again? Is it possible to have protection from these for modem? How do I check ...
14
votes
3answers
16k views

Is it safe to have a DNS record pointing to 127.0.0.1?

My development server is on my local machine (127.0.0.1). I have created an A record in my DNS settings that points dev.mydomain.com to 127.0.0.1 so that I can use this domain name for accessing my ...
14
votes
1answer
1k views

Attackers of Google DNS hijacking

As we know Google DNS server (8.8.8.8) in 14th and 15th March was hijacked in Sao Paulo. And subsequent to this event, BGPmon.org announced an alert. Now, In a course assignment, we are asked to find ...
13
votes
2answers
3k views

How does dnsleaktest.com find my DNS provider

Can't see how they find this over the web. I'm on Windows, its in my network config. It changes when I use a VPN provider, but not when I use a local socks proxy connected to a remote server over ...
13
votes
2answers
782 views

How was The Pirate Bay datacenter kept hidden?

How were The Pirate Bay's servers kept hidden for so long? You would think that it would be easy finding the servers that so many DNS servers are pointing to. Tracing the chain to the main datacenter ...
13
votes
2answers
2k views

Why do browsers or operating systems not have default DNSSEC validation?

Many resolvers (including TLDs and Root TLDs) support DNSSEC, also Google's OpenDNS servers support it. Yet it isn't checked on the client side by default. Why is this?
13
votes
2answers
2k views

DNSSEC signing algorithms

Virtualmin supports a flurry of algorithms for DNSSEC: RSASHA1, RSASHA256, RSAMD5, DSA, DH, HMAC-MD5(???), NSEC3RSASHA1, NSEC3DSA. If I understand correctly, there's Proof of Concept available for ...
12
votes
4answers
8k views

Is NTP vulnerable to DNS poisoning or spoofing attacks?

Scenario: Attacker somehow compromises the DNS lookup for the NTP server used by the victim (a web application) Victim sends DNS request for e.g. ntp.pool.org, which is responded to by attacker to ...
12
votes
3answers
593 views

Should the average user care about DNS security?

Denise is an average user who goes with the default settings of her OS and home router. She knows that her browser and email client use DNS and she's worried because I told her that the DNS protocol ...
12
votes
3answers
1k views

What are locked domain names technically?

I just learned about domain name locking at registrar level. I’m having problem to understand what it is, all I found is it’s a protection against domain name takeover through transfer. Now, I also ...
12
votes
2answers
415 views

Using Single Domain Name to Identify Multiple Servers Improves Security? (Google's use of 1e100.net)

Since 2009, Google has been using a single domain name to identify its servers across multiple products: Following standard industry practice, we make sure each IP address has a corresponding ...
11
votes
1answer
1k views

Should OS information be in DNS?

We are having an internal discussion about system naming conventions and there is a disagreement about including the type of OS a system is running in the DNS host record. One suggestion was to ...
11
votes
1answer
22k views

DNS Spoofing vs DNS Cache Poisoning

What is the difference between DNS Spoofing and DNS Cache Poisoning ??? It seems like there are little differences between two attacks, with an exception that DNS server is actually might cache the "...
11
votes
2answers
4k views

How does DigitalOcean DNS verify the owner of a domain?

Say you purchase a domain on Namecheap, but want to host DNS on DigitalOcean. DigitalOcean, says to simply tell your registrar to use DO's nameservers, then set up your DNS for that domain on DO. ...