34 votes
Accepted

How discoverable are IPv6 addresses and AAAA names by potential attackers?

Malicious bots don't guess IPv4 addresses anymore. They simply try them all. On modern systems this can take as little as a few hours. With IPv6, this is not really possible any longer, as you've ...
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25 votes
Accepted

NTP Service Auto-Discovery

You can specify an NTP server via DHCP, or Group Policy, or DNS SRV records. DHCP: GPO: SRV Record: If your client is unable to leverage any of those mechanisms... you can also pretty safely ...
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  • 54.8k
23 votes
Accepted

What is '_autodiscover._tcp' in DNS settings?

SRV DNS records allow the use of DNS for publishing services and service discovery. Their main use is to allow services to run easily on non-standard ports and to reduce the configuration burden when ...
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  • 70.6k
8 votes

How discoverable are IPv6 addresses and AAAA names by potential attackers?

I've found that MANY bots these days are not guessing, with IPv4 or IPv6. Security through obscurity is not security at all. Obscurity simply delays / reduces the number of attacks for a while, and ...
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6 votes

How to setup auto-configure email for Android Mail app on your server?

I wrote up autoconfig (Thunderbird/Mozilla standard) + autodiscover (Microsoft standard) and RFC 6186 as an Ansible 'role' - but with plenty of text to explain what's going on. Summary: Setup RFC 6186 ...
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6 votes

How discoverable are IPv6 addresses and AAAA names by potential attackers?

Regarding AAAA records: DNS is traditionally unencrypted. While there is a family of standards (DNSSEC) for signing DNS, the encryption of DNS records has had a far more haphazard deployment process, ...
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  • 406
5 votes

What is '_autodiscover._tcp' in DNS settings?

It is likely related to your Exchange server. Autodiscover for Exchange.
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4 votes

Does Outlook continue to auto-discover account settings for already configured accounts? Can it be prevented?

I know, very old thread, but I stumbled on it. Outlook will try among other things a Root Domain query. Many Websites that have secure certificates will have a wildcard on the certificate. So ...
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  • 41
3 votes
Accepted

Bypass Autodiscover step

Not ideal, but a workaround is via registry on the client computers. (of course you may set this trough Group Policy) In keys : HKEY_CURRENT_USER\Software\Microsoft\Office\x.0\Outlook\AutoDiscover ...
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  • 1,931
3 votes
Accepted

Outlook still connects to on-premise Exchange after migration

Most likely, you still have an AD record that points clients to your on-premise Exchange during Autodiscovery. The steps to resolve this can be found in the excellent article Outlook still trying to ...
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2 votes
Accepted

Discover webserver on a network

Make sure you set the hostname for the computer. Assuming that every network you connect to runs its own DNS/dhcp then when its gets a dhcp address it should (in a normal setup) register its hostname ...
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  • 146
2 votes

Discover webserver on a network

You could use nmap to scan the network. If for example your web server runs on tcp:80 and your subnet is 192.168.1.0, then you can try : nmap 192.168.1.0/24 -p 80 on my network I get Starting ...
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  • 71
2 votes
Accepted

Exchange 2010: EXPR section missing from Autodiscover for some users

To the best of my knowledge (meaning I tried lots and lots of things) I'm pretty sure in my case the issue was that the "broken" users had MAPIBlockOutlookRpcHttp set to true. Setting that to false ...
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2 votes

Outlook Autodiscover Protocol Updated? (or broken?)

I'm not aware of "outlook autodiscovery" working at all without the "proper" DNS TXT and SRV records in your domain. But these are non-standard and may differ depending on how you, your ISP, or your ...
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2 votes

How do I Clear the Windows Mail Autodiscover Cache?

Toclear the Logs is just like this: In the from folder %localappdata%\Microsoft\Outlook\ you will find files "numbers_ Autodiscover.xml" Delete all those files and restart Outlook Source: https://...
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2 votes
Accepted

Zabbix network discovery of puppet managed network

The most flexible and powerful approach will be to use the Zabbix API to create hosts and link them to appropriate templates from Puppet. One project that handles that is https://github.com/voxpupuli/...
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  • 2,304
2 votes

How to reliably keep a list of servers in a company network

DNS. Every network should have name services, sometimes bundled or integrated as DNS, DHCP, and IPAM (DDI).
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2 votes

How to solve issues with Exchange's Autodiscover (xml) and any peculiar clients like Windows Communication Apps [HxTsr.exe] with complex DNS config?

Tips Do create an extra test account. Use https://testconnectivity.microsoft.com/tests/Eas/input as sanity check. This test https://testconnectivity.microsoft.com/tests/O365Eas/input is smarter, but ...
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  • 131
1 vote

autodiscover for 2 completly different domains

How did you add the domain maruna.com to your email addresses? By Email Address Policy or alternative UPN suffix? Do you get any internal/external hostnames related with the domain maruna.com if you ...
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  • 1,323
1 vote
Accepted

For FreeIPA autodiscovery to work, what SRV records must exist on the DNS server?

If your authoritative DNS server is not FreeIPA, you can run the following command on your IPA server to generate the necessary DNS records, which you can then go and put into your authoritative DNS ...
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  • 3,395
1 vote
Accepted

Consul as service discovery and configuration server in on premises local network

Consul is not a good fit for your use case, because it expects to have a quorum of nodes available for consensus. It is also, like all distributed consensus systems, a finicky balky piece of sh... ...
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  • 94.5k
1 vote

Office 365 Outlook Autodiscover using a reverse proxy - bad approach?

Office 365 and Exchange Online environment has a different character from the Exchange on-Premises environment. In Exchange on-Premises environment, the organization uses a dedicated Public facing ...
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  • 759
1 vote

Outlook still connects to on-premise Exchange after migration

Note that Outlook, even when it uses AutoDiscover, may not properly update a profile to point to the new mailbox in O365. Older versions of Outlook (prior to OL2016) store values in a profile for on-...
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  • 11
1 vote
Accepted

Having an issue with Outlook out of office that seems to be caused by autodiscover

I'm having an issue where users can set the out of office for outlook, but response only go internally but not externally. Does the externally here mean the same domain' user with external Outlook ...
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  • 366
1 vote

Having an issue with Outlook out of office that seems to be caused by autodiscover

The DNS entry for Autodiscover is completely unnecessary unless you have internal clients who are using Outlook but are NOT on the domain. When a client is on the domain and is able to see the ...
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  • 2,854
1 vote
Accepted

Exchange 2013 Internal and External URLs with multiple servers and certificates

Using a wildcard certificate will be problematic in your situation, as internal and external names are in separate domains. Rather than a Wildcard certificate, request a SAN (Subject Alternative Name) ...
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  • 955
1 vote
Accepted

How should I test all 300 of my AcceptedDomains for Autodiscover issues?

Here is the script I came up with. I still need a way to easily just get all the active primary SMTP addresses, but this is a start. #This script tests the naked domain and autodiscover record for ...
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1 vote

Exchange 404 not found /autodiscover/autodiscover.xml

First of all this error is not critical, more just for informative purposes. In order to fix this you should understand why this error occurs. Exchange does monitoring of its own. The Endpoint /...
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  • 181
1 vote
Accepted

AutoDiscover not working yet everything is configured correctly

This is likely due to the numeric certificate installed on the server. It is not valid for the name "autodiscover.waqaskhattak.com". If you try to access https://autodiscover.waqaskhattak.com/...
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  • 1,931
1 vote

Email Autodiscovery Not Being Probed By Android

I'm not aware of "outlook Autodiscovery" working properly without having hints in the domain DNS. I assume you are talking about an "Exchange Server", but can you be a bit more specific about which "...
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