<p><code>seed.bitcoin.sipa.be</code> and the other DNS seeders listed <a href="https://github.com/bitcoin/bitcoin/blob/aa624b61c928295c27ffbb4d27be582f5aa31b56/src/chainparams.cpp#L127" rel="nofollow noreferrer">here</a> will return a list of IP addresses when given a DNS query. Bitcoin Core then takes all of those IP addresses and adds them to its internal address manager. It will then attempt connecting to the addresses stored in its address manager which, after the first start, will consist of more than just the nodes returned by the DNS seeders.</p>

CC BY-SA 3.0
2017-10-11T12:49:08.367Z
Thanks. So this means that even if DNS seed returns  a few invalid IP adresses it's not a problem because Bitcoin Core takes all IP adresses and finds the working ones.
JPX
CC BY-SA 3.0
2017-10-11T14:17:12.170Z
Yes. And there are multiple DNS seeders so it will get nodes from other DNS seeders too.
Ava Chow
CC BY-SA 3.0
2017-10-15T13:20:08.397Z
If you define `addnode=seed.xxxxxx.com` or type `addnode seed.xxxxxx.com add` does Bitcoin Core add all IP addresses or just one IP address to it's address manager?
JPX
CC BY-SA 3.0
2017-10-15T15:16:34.837Z
You cannot add DNS seeders via the command line or the RPC commands. `addnode` will add the one node that you enter to the address manager and then attempt to connect to it. There are no "all IP addresses" for it to even add; you are only giving it one IP address.
Ava Chow
CC BY-SA 3.0
2017-10-10T20:36:44.073Z
2017-10-10T20:36:44.073Z
Ava Chow
<p>The bitcoin client will first try to scan for previous known IPs, once that fails, it will indeed fall back on DNS seeds.</p>

<p>It will resolve <code>seed.bitcoin.sipa.be</code> to a list of IP adresses and it will pick one of them.</p>

CC BY-SA 3.0
2017-10-10T20:32:50.193Z
What if there is multiple DNS seeds? Will client pick one IP address from each DNS seed?
JPX
CC BY-SA 3.0
2017-10-10T19:43:55.653Z
2017-10-10T19:43:55.653Z
Jan Janssen
<p>Command</p>

<blockquote>
  <p>nslookup seed.bitcoin.sipa.be</p>
</blockquote>

<p>gives a list of 40 nodes.</p>

<p>1) Does Bitcoin wallet take all nodes from that list?</p>

<p>or</p>

<p>2) Does Bitcoin wallet behave like normal application that resolves seed.bitcoin.sipa.be and take only one IP address to connect.</p>

<client><seed><dns>
How Bitcoin client handles DNS seeds?
JPX
# How Bitcoin client handles DNS seeds?

(Asked by: username_0 on 2017-10-10)

Command

> nslookup seed.bitcoin.sipa.be

gives a list of 40 nodes.

1) Does Bitcoin wallet take all nodes from that list?

or

2) Does Bitcoin wallet behave like normal application that resolves seed.bitcoin.sipa.be and take only one IP address to connect.

**Tags:** client, seed, dns


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## 2 answers

### Answer by username_1 on 2017-10-10. Score: 0 | Accepted answer

`seed.bitcoin.sipa.be` and the other DNS seeders listed [here](https://github.com/bitcoin/bitcoin/blob/aa624b61c928295c27ffbb4d27be582f5aa31b56/src/chainparams.cpp#L127) will return a list of IP addresses when given a DNS query. Bitcoin Core then takes all of those IP addresses and adds them to its internal address manager. It will then attempt connecting to the addresses stored in its address manager which, after the first start, will consist of more than just the nodes returned by the DNS seeders.

> **Comments:**
> **username_0**: Thanks. So this means that even if DNS seed returns  a few invalid IP adresses it's not a problem because Bitcoin Core takes all IP adresses and finds the working ones.  
> **username_1**: Yes. And there are multiple DNS seeders so it will get nodes from other DNS seeders too.  
> **username_0**: If you define `addnode=seed.xxxxxx.com` or type `addnode seed.xxxxxx.com add` does Bitcoin Core add all IP addresses or just one IP address to it's address manager?  
> **username_1**: You cannot add DNS seeders via the command line or the RPC commands. `addnode` will add the one node that you enter to the address manager and then attempt to connect to it. There are no "all IP addresses" for it to even add; you are only giving it one IP address.  

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### Answer by username_2 on 2017-10-10. Score: 0

The bitcoin client will first try to scan for previous known IPs, once that fails, it will indeed fall back on DNS seeds.

It will resolve `seed.bitcoin.sipa.be` to a list of IP adresses and it will pick one of them.

> **Comments:**
> **username_0**: What if there is multiple DNS seeds? Will client pick one IP address from each DNS seed?  

---

