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Plusnet DNS servers.. any limits on lookups?

7up
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Plusnet DNS servers.. any limits on lookups?

Hey PN,
I'm writing my own DNS server to use on my local LAN. Reason for this is that i need local lookups for my lan aswell as the internet.
So it needs to use an external DNS server for its lookups. Currently i've been using google for testing purposes but who knows what their policies are.and i have a hunch i may well get banned after extensive testing lol.
So I was wondering if i can use PN's DNS servers.. and is there a limit? - I'm basically using the same domains with each run of the program so the TTL gets completely ignored in the testing phase. So.. do your servers ban / refuse lookups of the same domains after X queries? - Do you have any objections to me using your DNS for testing my DNS server lookups?
Thanks,
7up
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12 REPLIES 12
Chris
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Re: Plusnet DNS servers.. any limits on lookups?

Sorry for no reply, I'm not actually sure of the answer. I'll fire off an email and let you know if/when I get a response.
Former Plusnet Staff member. Posts after 31st Jan 2020 are not on behalf of Plusnet.
bobpullen
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Re: Plusnet DNS servers.. any limits on lookups?

I'm not really sure I understand what you're trying to achieve here?
If you plan on running your own DNS server, then why have any dependency on ours?
If there are high volumes of DNS lookups from a fixed IP, then it may be frowned upon. I don't think what you're trying to do is going to cause you to get automatically throttled/locked out though. The customer here was generating more than half a million servfails a day.

Bob Pullen
Plusnet Product Team
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Estragon
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Re: Plusnet DNS servers.. any limits on lookups?

The thread just stops Bob :). Did he crack the problem do you know, or did the requests just stop after he committed suicide?
I have to admire his tenacity in trying to sort it, and the effort npr put into helping him.
7up
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Re: Plusnet DNS servers.. any limits on lookups?

Howdi bob  Wink
Quote from: Bob
I'm not really sure I understand what you're trying to achieve here?

Let me explain..
On my lan I have the apche webserver setup running several virtual hosts. Now in my hosts file i can set those up no problem but the moment i type in the short name (eg cosmo) from another computer, that no longer works as it doesn't have a hosts file setup and doing it manually.. well thats not ideal.
So I decided to write my own dns server that will perform DNS for my local lan but also provide resolution for the outside world - by sending it's own requests to another external DNS server - EG you or google.
I know google have the processing power but i've no idea what their policy is on TTL ignorance. Thats where you guys come in. At the moment I'm working on the code that handles multiple records in one reply (eh hostname, name server, ip). Now for testing i obviously need it to use a dns server that isn't going to get upset with my ignoring the TTL values from the last X number of requests.
Quote from: Bob
If you plan on running your own DNS server, then why have any dependency on ours?

It won't be once it's finished and working reliably - at that time i'll set it back to google and it will obey the TTL values. At the moment i just need to set it to use a server for testing that won't block it.
Quote from: Bob
If there are high volumes of DNS lookups from a fixed IP, then it may be frowned upon. I don't think what you're trying to do is going to cause you to get automatically throttled/locked out though. The customer here was generating more than half a million servfails a day.

Nothing like half a million coming from me. Maybe a few hundred.. but my main concern is that your server might not like my requests ignoring the previously advised TTL.
I know in an ideal world it would perform proper dns lookups via the main zones etc but i can't be faffed with all that.. especially when most routers just use their ISP.
Thanks for the pi idea but i'm not a big fan of non GUI programs that run via a command interface lol. Once my dns server is finished, it's going into a mini-itx fanless unit that will also host some other cool stuff  Smiley
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bobpullen
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Re: Plusnet DNS servers.. any limits on lookups?

Quote from: Estragon
The thread just stops Bob :). Did he crack the problem do you know, or did the requests just stop after he committed suicide?

He bought a couple of new cams I think.
Quote from: 7up
On my lan I have the apche webserver setup running several virtual hosts. Now in my hosts file i can set those up no problem but the moment i type in the short name (eg cosmo) from another computer, that no longer works as it doesn't have a hosts file setup and doing it manually.. well thats not ideal.

Fair enough.
Quote from: 7up
I know google have the processing power but i've no idea what their policy is on TTL ignorance. Thats where you guys come in. At the moment I'm working on the code that handles multiple records in one reply (eh hostname, name server, ip). Now for testing i obviously need it to use a dns server that isn't going to get upset with my ignoring the TTL values from the last X number of requests.

I honestly can't see a few hundred requests causing any noticeable problems, irrespective of the TTL adherence.
Quote from: Estragon
I know in an ideal world it would perform proper dns lookups via the main zones etc but i can't be faffed with all that.. especially when most routers just use their ISP.

Quote from: 7up
So I decided to write my own dns server...

Writing something bespoke yourself strikes me as more of a 'faff' than using an out of the box resolver; having said that, I'll admit to it not really being my forté Wink

Bob Pullen
Plusnet Product Team
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7up
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Re: Plusnet DNS servers.. any limits on lookups?

Quote from: Bob
Quote from: Estragon
I know in an ideal world it would perform proper dns lookups via the main zones etc but i can't be faffed with all that.. especially when most routers just use their ISP.

Quote from: 7up
So I decided to write my own dns server...

Correct text, wrong username quoted LOL  Cheesy
Quote from: Bob
Writing something bespoke yourself strikes me as more of a 'faff' than using an out of the box resolver; having said that, I'll admit to it not really being my forté Wink

Yes and no. Yes it's faff because it means writing code, debugging, researching etc... No because I can use my own features that I want such as a blacklist etc. With a little one growing fast and kids these days being tech hungry I figured my own dns could block the nastys / give restricted access to approved sites. It also means I can set it up to use a database rather than zone files which have to be reloaded everytime a record is changed. If its using a database instead then yes it has the read time (negligible really) but record changes will take instant effect without restarts of the service.
Plus there aren't many DB DNS servers out there for windows.. so i figured it would be a nice addition to my CV too  Wink
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pwatson
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Re: Plusnet DNS servers.. any limits on lookups?

Sounds like an ideal use for a Raspberry Pi...
I'm puzzled by your decision to use a database - How will you deal with time to live?
7up
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Re: Plusnet DNS servers.. any limits on lookups?

Quote from: pwatson
Sounds like an ideal use for a Raspberry Pi...

Yes maybe.. but you have to remember that it's someone elses code, may / not have the features wanted...
Quote from: pwatson
I'm puzzled by your decision to use a database - How will you deal with time to live?

In what way? - TTL for my local LAN names or external lookups? - External lookups will just be recorded in the DB with their TTL and the lookup time so that the dns server knows whether it can perform a fresh lookup or not. Or am I misunderstanding your question?
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npr
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Re: Plusnet DNS servers.. any limits on lookups?

Quote from: 7up

Yes maybe.. but you have to remember that it's someone elses code, may / not have the features wanted...

What features do you need, there's some very good and free DNS software out there.
7up
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Re: Plusnet DNS servers.. any limits on lookups?

Whitelist / blacklist (with redirects - error pages), timed / scheduled white/black list, database backend (no zone files), runs as a windows service (with a seperate admin program), free, supports LAN network names aswell as external domains and that is just for a start.
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MJN
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Re: Plusnet DNS servers.. any limits on lookups?

Quote from: 7up
Now for testing i obviously need it to use a dns server that isn't going to get upset with my ignoring the TTL values from the last X number of requests.

TTL values specify the maximum length of time that you should cache a record for not the minimum. Indeed, there is no obligation to cache records at all.
With only hundreds of queries being made any 3rd party DNS server is not going to even notice given they will be routinely dealing with 1000's of queries per second without breaking a sweat.
7up
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Re: Plusnet DNS servers.. any limits on lookups?

Quote from: MJN
Quote from: 7up
Now for testing i obviously need it to use a dns server that isn't going to get upset with my ignoring the TTL values from the last X number of requests.

TTL values specify the maximum length of time that you should cache a record for not the minimum. Indeed, there is no obligation to cache records at all.

Actually you have a point since PNs dns is only caching not authoritive their TTL won't really matter. Completely missed that one. Thanks MJN Wink
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