Multi Master/Primary Authoritative DNSSEC DNS Nameserver With Synced/Replicated COMMON Dir/Vol For BIND

Terik Erik Ashfolk aterik at outlook.com
Fri Sep 27 21:53:48 UTC 2024


According to the page
https://blog.apnic.net/2021/08/25/multi-signer-dnssec-models/
in MODEL 2.
I added an improved image as attachment.
<img alt="ZSK-signing" src="cid:ImportZSK-PublishDSofKSK.jpg" />
MULTI-ZSK-SIGNING IS ONE OF THE SOLUTION, and appears to be 
suitable for my case.

So, multi-signing with ZSKs from multiple nameservers would have 
worked,
when nameservers were using separate "zones" & "keys" folder,

I needed to sign n1's zone file with n2's ZSK & with n3's ZSK.
I needed to sign n2's zone file with n1's ZSK & with n3's ZSK.
I needed to sign n3's zone file with n1's ZSK & with n2's ZSK.

Because 3 nameservers are using SYNCED/REPLICATED shared 
directories & files,
so each ZSK & KSK are available to other nameservers.

for "key-directory"
n1 using "/mnt/vol/v1/etc/bind/n1/keys"
n2 using "/mnt/vol/v1/etc/bind/n2/keys"
n3 using "/mnt/vol/v1/etc/bind/n3/keys"

and shared common directory for BIND keys is
"/mnt/vol/v1/etc/bind/keys"

and shared directory is
"/mnt/vol/v1"

is there an option in BIND, that can monitor+enable additional ZSK 
signing from new ZSK key from other namerservers for same domain ?
if not, please add this as new feature in BIND.

if BIND itself cannot do the monitoring + multi-ZSK-signing now, 
then, HOW can i monitor the ".../bind/n1/keys" (or 
".../bind/n2/keys" or ".../bind//n3/keys" or ".../bind/keys" ) 
sub-dirs under shared-directory and find that BIND has began to use 
a new ZSK key ?

or HOW can i get a signal from BIND in each nameserver ? that, BIND 
has began to use a new ZSK key ?

so-that, i can trigger/run another script in each nameserver (which 
added new ZSK key) to begin signing my domain's zone file in other 
2 nameservers with the new ZSK.

example : if n1 added a new ZSK for "example.com" domain, then a 
"new-zsk-key-monitoring-script.sh" script will create 2 files
"signal-n2-ExampleCom-MZS-zskNUMBER.txt"
"signal-n3-ExampleCom-MZS-zskNUMBER.txt"
in the shared-bind-directory : "/mnt/vol/v1/etc/bind/keys".
Then "monitor-for-signal-file.sh" script running in n2 & n3, will 
get that signal, & run "multi-ZSK-sign-script.sh" to mulit ZSK signing.


Thanks in advance.

Erik.

Erik T Ashfolk.




On 9/26/24 7:26 PM, TErik Ashfolk wrote:
> Hello BIND Community.
> 
> Looking forward to your suggestions, advises on setup DNSSEC 
> enabled zones on multiple master/primary authoritative DNS server 
> (Nameserver) with synced/replicated common shared directories/volume.
> 
> 
> Please skip the section(s) that you dont need to read/scan,
> 
> & goto the QUESTIONS , the last section.
> 
> 
> OBJECTIVES (END-RESULT):
> 
> Trying to achieve HA (High-Availability <https://en.wikipedia.org/ 
> wiki/High_availability>), so-that, as long as 1 master/primary is 
> up/running, then my domains are still available to world, and 
> allowing users to obtain DNSSEC verified domain-name to IP-address 
> resolving, etc from BIND DNS server services.
> 
> 
> 
> RESOURCES:
> 
> • Servers : rented 3 servers on 3 locations from different server 
> providers.
> 
> • Domain : I have multiple domains from domain providers 
> (registrar) . Here i will use "example.com"
> 
> • Each server has 1 IPv4-address, 1 IPv6-address.
> 
> • Domain provider's "Use your own Nameserver" is pointed to 3 
> hostnames in 3 nameservers : n1.example.com ( 192.10.2.11 , 
> 2001:db8:1::1 ) , n2.example.com ( 198.51.100.12 , 
> 2001:db8:2::2 ) , n3.example.com ( 203.0.113.13 , 2001:db8:3::3 ) 
> IP-addresses.
> 
> • Each IP-adrs has it's RDNS setup done, to correspond & match with 
> nameserver's hostname.
> 
> • Using Debian GNU/Linux 12 (bookworm) OS in each server. ( Server 
> operator can use any other OS, its their choice/preference. ) ( By 
> the way, Debian GNU/Linux is base of Ubuntu Linux, kind of similar 
> to: RedHat Enterprise GNU/Linux is base of Fedora Linux. )
> 
> • Using ISC BIND9 (9.18.0 , specifically now : 9.18.28) DNS server 
> software, in each server. ( Server operator can use any other DNS 
> server, its their choice/preference. )
> 
> 
> ABOUT FILE/DIRECTORY REPLICATION:
> 
> • For directories & files replication/sync purpose, using Gluster 
> software (1 <https://en.wikipedia.org/wiki/Gluster>,2 <https:// 
> docs.gluster.org/en/latest/>,3 <https://serverfault.com/ 
> a/1165339/217110>,4 <https://www.howtoforge.com/how-to-install- 
> glusterfs-on-debian-12/>). ( There are many other choices for 
> server operators:Multi-Master Replicaiton <https:// 
> en.wikipedia.org/wiki/Multi-master_replication>,List <https:// 
> en.wikipedia.org/wiki/List_of_cluster_management_software>), its 
> their own choice what suits best/works for their need/purpose.
> 
> • When any file/directory changes ( i.e: in "n1" server ) , then 
> the replication/sync software that is installed/monitoring , will 
> nearly immediately or within few seconds, begin to make same 
> changes to same file/dir in server-operator's other servers ( n2 , 
> n3 ), that are member of replication/sync volume/directory. These 
> replication software uses time-server to have accurate time. 
> Whichever edit/creation/deletion/modification is done last, that 
> takes priority & duplicated/replicated/synced.
> 
> 
> 
> SHARED/COMMON STORAGE/VOLUME/DIRECTORY:
> 
> • I created a large file ("data-s1.img"), ~ 300 MB in size, inside 
> root-partition , at "/storage/s1/data-s1.img" . Formatted with XFS 
> filesystem creation/make tools . Attached large-file into a loop 
> block device . Mounted it in "/data/s1" directory . Created a 
> systemd service "mount-storage.service" in Debian to do previous 
> steps one after another, so-that it can succeed in mounting during 
> boot , (as "/etc/fstab" was not suitable for this purpose) . Others 
> can create/use a 2nd partition in same storage drive (i.e: "/dev/ 
> sda2") or add another storage drive (i.e: "/dev/sdb") in server . 
> Others can use a script (or "/etc/fstab") during boot to mount, etc.
> 
> • after above steps, replication software (Gluster) was used to 
> create replication volume "v1" inside the storage-mount-point ("/ 
> data/s1") , so it became "/data/s1/v1" . i configured gluster to 
> enable SSL/TLS based secure connection for replication process. 
> Gluster also needs user to mount the volume as "glusterfs" type 
> mount-point to monitor data r/w & replicate, & its done in : "/mnt/ 
> vol/v1" mount-point of volume "v1" . Followed stepshere <https:// 
> serverfault.com/a/1165339/217110>(& changed file/dir names).
> 
> • the files+dirs under "/mnt/vol/v1/" is replicated/synced in each 
> server, available/accessible in each server, in same location, has 
> exact same contents.
> 
> • Created "/mnt/vol/v1/etc/bind" directory for BIND aka named aka 
> DNS server aka nameserver software usage. Applied : chgrp bind / 
> mnt/vol/v1/etc/bind
> 
> • Moved the "zones" dir+files from "/etc/bind", from "n1" server 
> into the "/mnt/vol/v1/etc/bind/n1/" directory, & done similar for 
> "n2" & "n3" servers . Moved the "keys" dir+files from "/etc/bind", 
> from "n1" into the "/mnt/vol/v1/etc/bind/n1" directory, & done 
> similar for "n2" & "n3".
> 
> • so, "/mnt/vol/v1/etc/bind/keys" & "/mnt/vol/v1/etc/bind/zones" 
> folders/directories are COMMON for all servers: "n1", "n2", "n3".
> 
> • "n1" using "/mnt/vol/v1/etc/bind/n1/keys" dir & “/mnt/vol/v1/etc/ 
> bind/n1/zones” dir, so i created symlink inside to point+goto the 
> replicated/synced mount-point, command : ln -s "/mnt/vol/v1/etc/ 
> bind/n1/keys" "/etc/bind/keys" ; ln -s "/mnt/vol/v1/etc/bind/n1/ 
> zones" "/etc/bind/zones" ;
> 
> • "n2" using "/mnt/vol/v1/etc/bind/n2/keys" dir & “/mnt/vol/v1/etc/ 
> bind/n2/zones” dir . & created symlinks as shown above.
> 
> • "n3" using "/mnt/vol/v1/etc/bind/n3/keys" dir & "/mnt/vol/v1/etc/ 
> bind/n3/zones" dir. & created symlinks as shown above.
> 
> • Added permissions in AppArmor "/etc/apparmor.d/local/ 
> usr.sbin.named" file, for BIND/named, so that BIND/named can use 
> "v1" replicated-volume "/mnt/vol/v1" BIND directories : /mnt/vol/ 
> v1/etc/bind  , /mnt/vol/v1/etc/bind/zones , /mnt/vol/v1/etc/bind/ 
> keys , /mnt/vol/v1/etc/bind/n1/zones , /mnt/vol/v1/etc/bind/n1/ 
> keys in n1 server ( and i have done similar for n2 & n3 )  . Then 
> applied changes with command : apparmor_parser -r /etc/apparmor.d/ 
> usr.sbin.named
> 
> • Also applied or re-checked if the ownership-&-permission (O&P) 
> convention used+recommended by BIND/named for directories & files, 
> are applied/done on the dirs+files inside the "/mnt/vol/v1/etc/ 
> bind, etc.
> 
> 
> 
> DNSSEC & DNS:
> 
> • Each nameserver has BIND DNS server named daemon software . Each 
> BIND need to be Authoritative for my domains ("example.com" , 
> "example2.com", etc) & response back to any DNS servers/clients 
> query for my domains & for my subnet's reverse-zone . And each BIND 
> DNS server also need to serve/perform as a recursive DNS resolver 
> for any queries made into "localhost" ( 127.0.0.1 , ::1 ).
> 
> • Followed various related steps as-much-possible from "DNSSEC 
> Howto for BIND 9.9+ <https://wiki.debian.org/ 
> DNSSEC%20Howto%20for%20BIND%209%2E9%2B>” , ISCBIND docs for 9.18.28 
> <https://downloads.isc.org/isc/bind9/9.18.28/doc/arm/html/> ( that 
> i'm using now while writing this msg ) , etc . Debian OS will 
> update BIND in distro’s repo, & then my/op's servers will be 
> updated to that version . For next/latest version, goto ISC BIND 
> download pagehere <https://www.isc.org/download/>, search for "PDF" 
> word, select/click on the HTML / PDF doc version that you want to 
> read/follow.
> 
> • As each nameserver has different IP-addresses, so i've kept the 
> "named.conf", "named.conf.local", "named.conf.options" files in 
> the /etc/bind of server itself, for faster loading .
> 
> • The "named.conf" file has BIND ACLs, and include directives . 
> This file has same content in each server . Has “ acl LocalHostR 
> { 127.0.0.1; ::1; } ; LocalHostRv4 { 127.0.0.1; } ; LocalHostRv6 
> { ::1; } ; acl BlockedNets { 0.0.0.0/8 ; 192.0.2.0/24 ; 
> 224.0.0.0/3 ; 10.0.0.0/8 ; 172.16.0.0/12 ; 192.168.0.0/16 ; } ; acl 
> N1-IPv4 { 192.10.2.11; } ; acl N1-IPv6 {2001:db8:1::11; }; ” , etc, 
> (remove quote symbols) . ( i added more IPv4 & IPv6 in 
> BlockedNetslater ).
> 
> • The "named.conf.local" file has forward zones & reverse zones 
> declarations : each zone has "type primary;" directive/option set , 
> each zone has "file" directive with file located in replicated 
> volume location . Each local zones & each local reverse-zone for 
> IP-address) have "allow-query { LocalHostR; };" . My each domain's 
> zone (i.e: "zone "example.com" { ... };") declarations, & reverse- 
> zone for my own subnet, has "allow-query { any; };" .
> 
> •My domain “example.com”zone declaration in “named.local.conf” 
> file : “ zone "n1.example.com" { type master ; file "/mnt/vol/v1/ 
> etc/bind/zones/db.example.com" ; allow-query { any; } ; serial- 
> update-method unixtime ; key-directory "/mnt/vol/v1/etc/bind/n1/ 
> keys" ; dnssec-policy opPolicy ; inline-signing yes ; notify 
> no ; }; ” (remove quote symbols) . We allowed query from anyone . 
> By the way, i also have a sub-domain zone declared in 
> “named.local.conf” file as zone : “ zone "ns.example.com" { … }; 
> ” , nearly same as “example.com”.
> 
> • The "named.conf.options" file has “dnssec-policy 
> "opPolicy" { ... };”  , "options { ... };" , "logging { ... };" 
> sections/declarations . Logging uses the server's "/var/log/named" 
> dir ( into "Update_Debug.log" , "Security.log" , "BIND.log" files ).
> 
> • The “options { … };” in “named.conf.options” file :  “ options 
> { recursion yes ; allow-recursion { LocalHostR; } ; allow-query- 
> cache { LocalHostR; } ;allow-query-cache-on { LocalHostR; } ; 
> allow-query { LocalHostR; } ; allow-recursion-on { LocalHostR; } ; 
> empty-zones-enable yes ; blackhole { BlockedNets; } ; allow- 
> transfer { none; } ; auth-nxdomain no ; listen-on { N1-IPv4; 
> LocalHostRv4; } ; listen-on-v6 { N1-IPv6; LocalHostRv6; }; rate- 
> limit { ... }; }; ” (remove quote symbols). We restricted recursion 
> by allowing only LocalHostR, not external, not BlockedNets.
> 
> • DNS server, for non-dnssec part of DNS related queries & 
> responses for domain(s), IPv4-adrs, IPv6-adrs, etc (forward lookup/ 
> resolve , subnet IP-adrs reverse resolve/lookup ) WORKING FINE , 
> from n1 & n2 & n3 . Authoritative mode is working for my domains . 
> And "localhost" inside server can also provide website-name/domain- 
> name To IP-address resolve response, to the the local software/ 
> daemons/clients that are running inside server.
> 
> • To ENABLE DNSSEC : i add "dnssec-validation auto;" inside 
> "options" inside "named.conf.options" file , i add "key-directory 
> "/mnt/vol/v1/etc/bind/n1/keys" ; inline-signing yes;" in "zone 
> "example.com" { ... };" in "named.conf.local" file, etc , ( changed 
> the "n1" into "n2" for "n2" server, & similarly in n3. )
> 
> • For "dnssec-policy" directive about KSK & ZSK cert+key creation, 
> usage period, signing, validity, verification, etc , i'm using 
> shorter TTL period, etc , so-that dnssec/dns config lines can be 
> changed+applied quickly during DNSSEC setup phase : dnssec-policy 
> "opPolicy" {  ksk lifetime P88D algorithm RSASHA256 ;  zsk lifetime 
> 22D algorithm RSASHA256 ; dnskey-ttl PT10M ;  publish-safety 
> P2D ;  retire-safety P3D ;  purge-keys P3D ; signatures-refresh 
> P5D ;  signatures-validity P10D ;  signatures-validity-dnskey 
> P11D ; max-zone-ttl PT30M ;  zone-propagation-delay PT1H ;  parent- 
> ds-ttl PT1H ;  parent-propagation-delay PT1H ; nsec3param 
> iterations 0 optout yes salt-length 0 ;  };
> 
> 
> Now finally into the
> 
> QUESTIONS:
> 
> • How can i create 1 KSK key ( in "n1" server first ), for a 
> (single) domain ("example.com") and get the DS code from KSK key 
> and add that 1 DS in domain-provider ( to send to the TLD ), & 
> configure other 2 nameservers ( n2 , n3 ) to use that 1 DS record 
> from TLD & use that same/common 1 KSK file from the synced/ 
> replicated directory, while "type master;" is set for my domain/ 
> zone in each nameserver ?
> 
> ( Using 3 KSK & their 3 DS in domain-provider did not work, created 
> error indicators in DNSViz & in "DNSSEC-Annalyzer.VerisignLabs” 
> test sites, when each nameserver used separate directories, files, etc.
> 
> • if i specify same/COMMON (replicated) dir "/mnt/vol/v1/etc/bind/ 
> keys" & "/mnt/vol/v1/etc/bind/zones/zonename" inside 3 nameserver's 
> “named.conf.local” file domains/zones , Can BIND DNS server add 
> their own RRSIG response/lines for DNS records (into same zone 
> file) without removing earlier or other nameserver's RRSIG lines 
> (unless related ZSK key/period expired) ?
> 
> • How do i disable/clean/move/backup earlier DNSSEC keys/usages, & 
> setup DNSSEC completely as anew . ( Our zone TTLs are short 7m to 
> 1h , (during setup/test phase) , So within 7m to an hour, all 
> older-records should be discarded from caches. )
> 
> 
> Thanks in advance for helpful responses.
> 
> Erik.
> 
> Erik T Ashfolk.
> 
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