Only -? works.

It seems that something in the Bitcoin protocol for version 0.12.0+ has changed in such a way that the dnsseeder only gets a single addr (AdvertiseLocal) from a node it connects to.

I have forced dnsseed to connect to specific nodes with version 0.11.2, 0.12.0 and 0.12.1 and dnsseed only got multiple addr from 0.11.2 while 0.12.0/0.12.1 simply closed the connection after sending one node.

This is the output while connecting to a 0.11.2 node

Starting seeder...done
Starting 96 crawler threads...done
[16-05-31 18:18:19] 0/1 available (0 tried in 1464711499s, 0 new, 1 active), 0 banned; 0 DNS requests, 4 db queries
5.196.75.28:8333      : SEND version
5.196.75.28:8333      : RECV version
5.196.75.28:8333      : SEND verack
5.196.75.28:8333      : done processing version
5.196.75.28:8333      : RECV verack
5.196.75.28:8333      : version 70002
5.196.75.28:8333      : SEND getaddr
5.196.75.28:8333      : done processing verack
5.196.75.28:8333      : RECV ping
5.196.75.28:8333      : done processing ping
5.196.75.28:8333      : RECV addr
5.196.75.28:8333      : got 1000 addresses
5.196.75.28:8333      : got address 37.233.101.132:8333
5.196.75.28:8333      : added address 37.233.101.132:8333 (#0)
[...]2000 lines removed [...]
5.196.75.28:8333      : got address 104.200.151.89:8333
5.196.75.28:8333      : added address 104.200.151.89:8333 (#129)
5.196.75.28:8333      : done processing addr
5.196.75.28:8333: GOOD!!!

And this is the output while connecting to a 0.12.x node

Starting seeder...done
Starting 96 crawler threads...done
[16-05-31 18:28:10] 0/1 available (0 tried in 1464712090s, 0 new, 1 active), 0 banned; 0 DNS requests, 4 db queries
95.170.95.133:8333    : SEND version
95.170.95.133:8333    : RECV version
95.170.95.133:8333    : SEND verack
95.170.95.133:8333    : done processing version
95.170.95.133:8333    : RECV verack
95.170.95.133:8333    : version 70012
95.170.95.133:8333    : SEND getaddr
95.170.95.133:8333    : done processing verack
95.170.95.133:8333    : RECV ping
95.170.95.133:8333    : done processing ping
95.170.95.133:8333    : RECV addr
95.170.95.133:8333    : got 1 addresses
95.170.95.133:8333    : got address 95.170.95.133:8333
95.170.95.133:8333    : added address 95.170.95.133:8333 (#1)
95.170.95.133:8333    : done processing addr
95.170.95.133:8333: GOOD!!!

As you can see it only gets one entry: the one it has connected to (AdvertiseLocal).

I can't find any indication under what license this is published. Please clarify.

After How much time seeder marks the new node active and available? Where do i find code to change these settings?

Thanks for your help.

Any way to get this thing to use newline \n instead of a bunch of whitespace?

Starting 4 DNS threads for dnsseed.pigeoncoin.org on vps.pigeoncoin.org (port 53).......done
Starting seeder...done
Starting 96 crawler threads...done
                                                                                                                   [18-03-27 01:12:50] 0/85 available (                                                                                 [18-03-27 01:12:51] 0/125 available (0 tried in 1522113171s, 125 new,                                                  [18-03-27 01:12:52] 0/125 available (0 tried in 1522113172s, 125 new, 0 active), 0 banned; 0 DNS reque                                                                                                                                        [18-03-27 01:12                                                                                                        [18-03-27 01:12:55] 0/125 available (0 tried in                                                                         [18-03-27 01:12:56] 0/125 available (0 tried in 1522113176s, 61 new, 64 active                                         [18-03-27 01:12:57] 0/125 available (0 tried in 1522113177s, 45 new, 80 active), 0 banned; 0 DNS requests, 0 d                                                                                                                                 [18-03-27 01:12:59] 0/                                                                                                 [18-03-27 01:13:00] 0/125 available (0 tried in 152211                                                                 [18-03-27 01:13:01] 0/125 available (0 tried in 1522113181s, 0 new, 125 active), 0 ban                                 [18-03-27 01:13:02] 0/125 available (0 tried in 1522113182s, 0 new, 125 active), 0 banned; 0 DNS requests, 0 db querie                                                                                                                        [18-03-27 01:13:04] 0/125 avail                                                                                        [18-03-27 01:13:05] 0/125 available (0 tried in 1522113185s, 0 new, 125 active), 0 banned; 0 DNS requests, 0 db queries^C

Why is it that I can only get less than 3,000 nodes every two hours when crawling against a seed node at a time? Sometimes even just 5000 nodes in one night.

The DNS seeder runs and reports changes coming in on amount of DNS requests as well as having a lot of nodes found (.dump file checked and validated that it found good nodes) but it doesn't answer the requests properly.

Seems to me ignoreTill's intention is to ignore a node until some timepoint in the future. This expression appears to .. have the condition inverted, and only ignore nodes with ignoreTill in the past, and not ignore them if ignoreTill is in the future..

Is it just a question of creating a unique instance at some domain e.g. testnetseeder.mydomain.com or does the testnet need some special configuration to work correctly?

Fresh Lbuntu 17.10 install in Virtual box. No error on compilation.

I run
sudo ./dnsseed -h dnsseed -n localhost -m test. -p 53
...
Starting 4 DNS threads for dnsseed on localhost (port 53).......done
...

but
nslookup dnsseed localhost
;; connection timed out; no server could be reached

I span up a new DigitalOcean VM running Ubuntu 23.10. Installed all requirements:

sudo apt-get install build-essential libboost-all-dev libssl-dev

My gcc version:

$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-linux-gnu/13/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none:amdgcn-amdhsa
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 13.2.0-4ubuntu3' --with-bugurl=file:///usr/share/doc/gcc-13/README.Bugs --enable-languages=c,ada,c++,go,d,fortran,objc,obj-c++,m2 --prefix=/usr --with-gcc-major-version-only --program-suffix=-13 --program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id --libexecdir=/usr/libexec --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --enable-bootstrap --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-vtable-verify --enable-plugin --enable-default-pie --with-system-zlib --enable-libphobos-checking=release --with-target-system-zlib=auto --enable-objc-gc=auto --enable-multiarch --disable-werror --enable-cet --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic --enable-offload-targets=nvptx-none=/build/gcc-13-XYspKM/gcc-13-13.2.0/debian/tmp-nvptx/usr,amdgcn-amdhsa=/build/gcc-13-XYspKM/gcc-13-13.2.0/debian/tmp-gcn/usr --enable-offload-defaulted --without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu --with-build-config=bootstrap-lto-lean --enable-link-serialization=2
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 13.2.0 (Ubuntu 13.2.0-4ubuntu3) 
root@dnsseeder-main:~/litecoin-seeder# ls
Makefile  bitcoin.cpp  bitcoin.o   compat.h  db.h     dns.h  main.cpp     netbase.h     protocol.h   strlcpy.h  uint256.h  util.h
README    bitcoin.h    combine.pl  db.cpp    dns.cpp  dns.o  netbase.cpp  protocol.cpp  serialize.h  test.pl    util.cpp
root@dnsseeder-main:~/litecoin-seeder# nano netbase.h
root@dnsseeder-main:~/litecoin-seeder# g++ -v
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-linux-gnu/13/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none:amdgcn-amdhsa
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 13.2.0-4ubuntu3' --with-bugurl=file:///usr/share/doc/gcc-13/README.Bugs --enable-languages=c,ada,c++,go,d,fortran,objc,obj-c++,m2 --prefix=/usr --with-gcc-major-version-only --program-suffix=-13 --program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id --libexecdir=/usr/libexec --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --enable-bootstrap --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-vtable-verify --enable-plugin --enable-default-pie --with-system-zlib --enable-libphobos-checking=release --with-target-system-zlib=auto --enable-objc-gc=auto --enable-multiarch --disable-werror --enable-cet --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic --enable-offload-targets=nvptx-none=/build/gcc-13-XYspKM/gcc-13-13.2.0/debian/tmp-nvptx/usr,amdgcn-amdhsa=/build/gcc-13-XYspKM/gcc-13-13.2.0/debian/tmp-gcn/usr --enable-offload-defaulted --without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu --with-build-config=bootstrap-lto-lean --enable-link-serialization=2
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 13.2.0 (Ubuntu 13.2.0-4ubuntu3)

And trying to build fails with error:

$ make
g++ -std=c++11 -pthread -O3 -g0 -Wall -Wno-unused -Wno-sign-compare -Wno-reorder -Wno-comment -c -o dns.o dns.cpp
g++ -std=c++11 -pthread -O3 -g0 -Wall -Wno-unused -Wno-sign-compare -Wno-reorder -Wno-comment -c -o bitcoin.o bitcoin.cpp
g++ -std=c++11 -pthread -O3 -g0 -Wall -Wno-unused -Wno-sign-compare -Wno-reorder -Wno-comment -c -o netbase.o netbase.cpp
In file included from netbase.cpp:13:
strlcpy.h:27:15: error: ‘size_t strlcpy(char*, const char*, size_t)’ redeclared inline without ‘gnu_inline’ attribute
   27 | inline size_t strlcpy(char *dst, const char *src, size_t siz)
      |               ^~~~~~~
In file included from /usr/include/features.h:502,
                 from /usr/include/x86_64-linux-gnu/c++/13/bits/os_defines.h:39,
                 from /usr/include/x86_64-linux-gnu/c++/13/bits/c++config.h:679,
                 from /usr/include/c++/13/bits/requires_hosted.h:31,
                 from /usr/include/c++/13/string:38,
                 from netbase.h:7,
                 from netbase.cpp:6:
/usr/include/x86_64-linux-gnu/bits/string_fortified.h:150:1: note: ‘size_t strlcpy(char*, const char*, size_t)’ previously defined here
  150 | __NTH (strlcpy (char *__restrict __dest, const char *__restrict __src,
      | ^~~~~
strlcpy.h:62:15: error: ‘size_t strlcat(char*, const char*, size_t)’ redeclared inline without ‘gnu_inline’ attribute
   62 | inline size_t strlcat(char *dst, const char *src, size_t siz)
      |               ^~~~~~~
/usr/include/x86_64-linux-gnu/bits/string_fortified.h:167:1: note: ‘size_t strlcat(char*, const char*, size_t)’ previously defined here
  167 | __NTH (strlcat (char *__restrict __dest, const char *__restrict __src,
      | ^~~~~
make: *** [Makefile:8: netbase.o] Error 1

Is it possible to compile the code on a Raspberry Pi 4? I get the following build errors

g++ -pthread -O2 -o dnsseed dns.o bitcoin.o netbase.o protocol.o db.o main.o util.o -lcrypto
/usr/bin/ld: main.o: in function ThreadStats': main.cpp:(.text+0x584): undefined reference to __atomic_load_8'
/usr/bin/ld: main.o: in function GetIPList': main.cpp:(.text+0xe7c): undefined reference to __atomic_fetch_add_8'
/usr/bin/ld: main.o: in function main': main.cpp:(.text.startup+0x47c): undefined reference to __atomic_store_8'
collect2: error: ld returned 1 exit status
make: *** [Makefile:5: dnsseed] Error 1

thank you
Michel

If a sufficient amount of AAAA records is associated with a DNS request, a buffer overflow will occur in write_record_aaaa; up to 11 bytes beyond the end of the output buffer can be overwritten.

Append this to dns.cpp:

const uint8_t addresses[19][20] = {
{ 0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x0B, 0x04, 0x00, 0x00, 0x00, 0x04,  },
{ 0x04, 0x00, 0x00, 0x00, 0x48, 0x00, 0x00, 0x24, 0x03, 0x00, 0x48, 0x00, 0x00, 0x1E, 0x03, 0x00, 0x00, 0x00, 0x31, 0xFF,  },
{ 0x04, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x00, 0xF6, 0xB7, 0xFF, 0xFF, 0xE1, 0xFF, 0xFF, 0xFC, 0x00, 0x00, 0xFF,  },
{ 0x06, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x00, 0x00, 0x20, 0x01, 0x00, 0x00, 0xFA, 0xFF, 0x00, 0x00, 0xFF, 0xFF,  },
{ 0x04, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x00, 0xF6, 0xB7, 0xFF, 0xFF, 0xE1, 0xFF, 0xFF, 0xFC, 0x00, 0x00, 0xFF,  },
{ 0x06, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x00, 0x00, 0x20, 0x01, 0x00, 0x00, 0xFA, 0xFF, 0x00, 0x00, 0xFF, 0xFF,  },
{ 0x04, 0x00, 0x00, 0x00, 0x03, 0xFF, 0x00, 0x00, 0x00, 0x02, 0x3A, 0xFF, 0xFF, 0x24, 0x03, 0x00, 0x00, 0x00, 0x00, 0xFF,  },
{ 0x06, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x0B, 0x04, 0x00, 0xFF, 0x08, 0x00,  },
{ 0x06, 0x00, 0x00, 0x00, 0x03, 0xFF, 0x00, 0x00, 0x30, 0x22, 0x3A, 0xFF, 0xFF, 0x24, 0x03, 0x00, 0x00, 0x00, 0x00, 0xFF,  },
{ 0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x80, 0x0B, 0x04, 0x00, 0x00, 0x00, 0x00,  },
{ 0x06, 0x00, 0x00, 0x00, 0x48, 0x00, 0x00, 0x24, 0x03, 0x00, 0x48, 0x00, 0x00, 0x24, 0x03, 0x00, 0x00, 0x00, 0x00, 0xFF,  },
{ 0x06, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x00, 0x00, 0x20, 0x01, 0x00, 0x00, 0xFA, 0xFF, 0x00, 0x00, 0xFF, 0xFF,  },
{ 0x06, 0x00, 0x00, 0x00, 0x03, 0xFF, 0x00, 0x00, 0x00, 0x02, 0x3A, 0xFF, 0xFF, 0x24, 0x03, 0x00, 0x00, 0x00, 0x00, 0xFF,  },
{ 0x04, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x0B, 0x04, 0x00, 0xFF, 0x08, 0x00,  },
{ 0x06, 0x00, 0x00, 0x00, 0x03, 0xFF, 0x00, 0x00, 0x30, 0x22, 0x3A, 0xFF, 0xFF, 0x24, 0x03, 0x00, 0x00, 0x00, 0x00, 0xFF,  },
{ 0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x80, 0x0B, 0x04, 0x00, 0x00, 0x00, 0x00,  },
{ 0x04, 0x00, 0x00, 0x00, 0x48, 0x00, 0x00, 0x24, 0x03, 0x00, 0x48, 0x00, 0x00, 0x24, 0x03, 0x00, 0x00, 0x00, 0x00, 0xFF,  },
{ 0x06, 0x00, 0x00, 0x00, 0x13, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x0B, 0x04, 0x00, 0x00, 0x00, 0x00,  },
{ 0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0xCF, 0x9A, 0x9A, 0x9A, 0x9A, 0x9A, 0x9A, 0x9A, 0x9A, 0x9A, 0x9A, 0x9A, 0x9A, 0x9A,  } };

int cb(void *opt, char *requested_hostname, addr_t *addr, int max, int ipv4, int ipv6) {
    uint32_t num = 0;
    while ( num < max && num < 19 ) {
        memcpy(&addr[num], addresses[num], 20);
        num++;
    }
    return num;
}

int main(void)
{
    const uint8_t in[] = {0x1B, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x23, 0x00,
                          0x7A, 0x08, 0x00, 0x00, 0xFF, 0x00, 0xFF};
    uint8_t out[BUFLEN];
    dns_opt_t opt;
    opt.port = 0;
    opt.datattl = 0;
    opt.nsttl = 0;
    opt.host = "";
    opt.ns = "";
    opt.mbox = "";
    opt.cb = cb;
    opt.nRequests = 0;
    dnshandle(&opt, in, sizeof(in), out);
    return 0;
}

$ g++ dns.cpp && ./a.out
*** stack smashing detected ***: <unknown> terminated
Aborted (core dumped)

Brought up by @TheBlueMatt recently. Not sure what's involved for adding support.

Can I use this software and bind9 in one server together?

Can you only support IPV4 discovery, can you add IPV6 recognition?

./dnsseed -p 5353 -h seed.testnet.bitcoin.sprovoost.nl -n ec2-18-195-105-234.eu-central-1.compute.amazonaws.com -m [email protected] --testnet
Supporting whitelisted filters: 0x1,0x5,0x9,0xd
Using testnet.
Loading dnsseed.dat...done
Starting 4 DNS threads for seed.testnet.bitcoin.sprovoost.nl on ec2-18-195-105-234.eu-central-1.compute.amazonaws.com (port 5353).......done
Starting seeder...done
Starting 96 crawler threads...done
[18-01-21 21:19:44] 759/6834 available (6388 tried in 999s, 1 new, 445 active), 35701 banned; 26 DNS requests, 7 db queriesterminate called after throwing an instance of 'std::ios_base::failure[abi:cxx11]'
  what():  CAutoFile::write : write failed: iostream error
Aborted (core dumped)

dnsstats.log

Hi,

I'm looking to use DNSseeder script ... without DNS. I don't have any DNS server.

I want to start crawling the network, by connecting it to 'localhost', a locally running Full Node. Possible ? How?

Thanks,

My fork of bitcoin-seeder is no longer working, but ti did initially. Upon troubleshooting I can see that it is not listening on IPv4, only IPv6. As my VPS only runs IPv4 I'm pretty sure this is why it's stopped working.

Is there a way to force it to only listen on IPv4?

[root@160398 ~]# netstat -nlp |grep 53
udp6 0 0 :::53 :::* 150/./dnsseed

Hi

I have a private network and want to use the dns application to resolve known hosts. How do i tell it to only search my network?

I have three full nodes talking to eachother. Does the dns app run on a fullnode? How does it know to search starting from one of my addresses?

thanks!

Best
Dave

I set up a sipa seeder and it is grabbing peers from a different coin that uses a different p2p port. Any recommendations for solving this?

Due to data-center operators (example: Hetzer) blocks/shutdowns of dns seeders (@schildback @jonasschnelli) because of alleged netscanning which can be against the datacenter TOC, support for crawling through TOR would be nice.

ThreadDumper saves the database to dnsseed.dat every 3200 seconds (~1 hour). It would be nice if it also saved upon graceful exit.

I am trying to understand why the seeder is only returning one IP in my case while there are hundreds of nodes connected to it. Is there any additional debug that can be enabled to find more info? I uncommented all the printf's but im still not getting clear into on why more active peers aren't being identified and returned in the DNS query. Thx.

More info: https://bitcointalk.org/index.php?topic=3515046.new#new

i want to run a dns seeder for bitcoin. i have registered a domain. How to setup nameservers pointing to dns seeder?

I currently have nameservers setup correctly with godaddy. I have added vps host ip address to register as a nameserver.

Type | Name | Value | TTL | Actions
-- | -- | -- | -- | --
A | @ | x.x.xxxx.x | 1 Hour | Edit
A | dnsseed | x.x.xxxx.x | 1 Hour | Edit
A | vps | x.x.xxxx.x | 1 Hour | Edit
NS | @ | ns59.domaincontrol.com | 1 Hour |  
NS | @ | ns60.domaincontrol.com | 1 Hour |  
NS | dnsseed | vps | 1 Hour

and i run

./dnsseed -h dnsseed.example.com -n vps.example.com
but when i check it, the dns seeder is NOT listening on port 53.
I run with ubuntu LTS 16 and i am running both daemon and dnseeder on the same machine.

This also not working

dig dnsseed.mydomain.com

$ dig dnsseed.example.org

; <<>> DiG 9.8.3-P1 <<>> dnsseed.example.org
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 3808
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0

What is wrong here?
I have opened port 53 TCP/UDP

Tor v3 and I2P addresses are too large for DNS seeding, and it would be unnecessary in the first place (also because it is not possible/practical to access DNS over these networks).

However, it could still be useful to collect them for other purposes. For example, in the Bitcoin Core release process we use the text output of a DNS seeder as input for generating the hardcoded list of seeds. We are going to need some kind of crawler that supports these addresses.

Hi, what license is this seeder? Can I use this freely as open source or I have to pay someone?

Hi!
Does the DNS return the list of IPs given by the below function?
void CAddrDb::GetIPs_(set& ips, uint64_t requestedFlags, int max, const bool* nets);
thankyou

It currently starts the seeder.

In db.cpp GetIPs_ there is a very strange code :
if (max > goodIdFiltered.size() / 2) max = goodIdFiltered.size() / 2; if (max < 1) max = 1;
Why do we return half of the good nodes ?

Seeder does not listen on ipv4 address, it works on ipv6 only.

If ThreadDumper wakes up to save to disk periodically, it may miss nodes that are otherwise good and won't save them to disk. This is because it basically is getting nodes to save to disk from CAddrDb from its two lists: ourId and unkId.

However, when the crawler threads run, they "take" IPs to check from the CAddrDb class. These nodes are temporarily "popped" off the internal lists ourId and/or unkId (only to be returned later once a good/bad result is determined by the crawler).

So if ThreadDumper wakes up while any crawlers are actively checking nodes.. those nodes won't get saved to disk. :'(

The variable "clientVersion" is compared with REQUIRE_VERSION(which is a protocol version) in the function IsGood,

if (clientVersion && clientVersion < REQUIRE_VERSION) return false;

while it is compared with 31900(which seems to be a client version v0.3.19) in the function GetBanTime.

if (clientVersion && clientVersion < 31900) { return 604800; }

I'm confused. What on earth should "clientVersion" be compared with? Client version or protocol version?
This is the output of bitcoin-cli.

$ bitcoin-cli getnetworkinfo
{
  "version": 170100,
  "subversion": "/Satoshi:0.17.1/",
  "protocolversion": 70015,
......
}

Looking forward reply. Thanks!

pthread_create(&threadDns, NULL, ThreadDNS, dnsThread[i])
may run many times?

Do anyone know where that value came from in Bitcoin source?

I get this error in debian 8

make

gcc -pthread -std=c99 -O3 -g0 -march=native dns.c -Wall -c -o dns.o
g++ -std=c++11 -pthread -O3 -g0 -march=native -Wall -Wno-unused -Wno-sign-compare -Wno-reorder -Wno-comment -c -o bitcoin.o bitcoin.cpp
g++ -std=c++11 -pthread -O3 -g0 -march=native -Wall -Wno-unused -Wno-sign-compare -Wno-reorder -Wno-comment -c -o netbase.o netbase.cpp
In file included from /usr/include/boost/mpl/aux_/na_assert.hpp:23:0,
from /usr/local/include/boost/mpl/arg.hpp:25,
from /usr/local/include/boost/mpl/placeholders.hpp:24,
from /usr/local/include/boost/iterator/iterator_categories.hpp:17,
from /usr/local/include/boost/iterator/iterator_adaptor.hpp:14,
from /usr/local/include/boost/iterator/transform_iterator.hpp:12,
from /usr/include/boost/algorithm/string/case_conv.hpp:17,
from netbase.cpp:14:
/usr/local/include/boost/mpl/assert.hpp:28:41: fatal error: boost/mpl/aux_/config/gpu.hpp: No such file or directory
#include <boost/mpl/aux_/config/gpu.hpp>
^
compilation terminated.
Makefile:8: recipe for target 'netbase.o' failed
make: *** [netbase.o] Error 1

A small number of Bitcoin Wallet for Android users are facing the problem that all three seed dns domains do not resolve. I file this issue to coordinate a debugging effort between the affected users and the operators of the seeds.

Bitcoin Wallet is using bitcoinj which uses standard Java API "InetAddress.getAllByName(seed)" for resolving. These three names are tried:

seed.bitcoin.sipa.be
dnsseed.bluematt.me
dnsseed.bitcoin.dashjr.org

If the issue surfaces, all three names cannot be resolved. Message in the log:

[PeerGroup STARTING] DnsDiscovery - Failed to look up DNS seeds from seed.bitcoin.sipa.be: java.net.UnknownHostException: Unable to resolve host "seed.bitcoin.sipa.be": No address associated with hostname

The affected users claim that at the same time there are not issues with other domains or any internet connectivity issues. They an reproduce the issue by moving back and forth an affected network.

Needless to say, DNS requests do not directly go to the seed dns servers but are relayed via the default DNS server if the network (usually set via DHCP). Its very well possible that an intermediate dns server modifies the request in a way the seeders do not understand. In the past, there was one such issue when certain DNS servers randomly camelcased the domain name in the request and the seeders were using case sensitive checks (violating the spec).

Since bitcoinj currently does not persist any peers across restarts or even parse address messages, failure to resolve any peer leads to being disconnected from the P2P network.

One app that might be helpful to debug issues on the Android side is DNS Lookup: https://play.google.com/store/apps/details?id=com.kodholken.dnslookup