RK - 2021/22 - LDN9 Sistem DNS v GNS3 - resitev Starc Aljaz¶
- Adapted from: rkvaje.lrk.si
Setup¶
Za laufanje BIND strezika bomo uporabljali Alpine ter matjazp/ubuntu-bind Docker image-a, ki jih v GNS3 uvozis z slednjim postopkom:
- zazeni GNS3
- toolbar -> Edit -> Preferences (slika 1)
- Na levi v sidebar-u izberi meni "Docker containers" (slika 2)
- Alpine
- Ubuntu-bind
- Izberi "new" za dodajanje novega template-a
- Izberi opcijo "New image: ter vpisi
ghcr.io/matjazp/ubuntu-bind:latest - vse ostale opcije pusti privzete in dodaj template (slika 5)
Networking scheme¶
| Ime naprave | Tip naprave |
|---|---|
| SW1 | Ethernet switch (builtin) |
| CLIENT1 | Alpine (docker) |
| DNS1 | matjazp/ubuntu-bind (docker) |
| DNS2 | matjazp/ubuntu-bind (docker) |
Networking config¶
Vsaki napravi v omrezju nastavimo lokalni IPv4 naslov, da bodo lahko med seboj komunicirale.
DNS1 - zone¶
Own domain¶
Dodamo zone db file import na konec datoteke named.conf.local.
cat << EOF >> /etc/bind/named.conf.local
zone "starc.rk" {
type master;
file "/etc/bind/db.rk.starc";
};
EOF
Definiramo zone db config (DNS record-e)
cat << EOF > /etc/bind/db.rk.starc
; starc.rk
\$TTL 604800
starc.rk. IN SOA ns1.starc.rk. hostmaster.starc.rk. (
1 ; Serial
604800 ; Refresh
86400 ; Retry
2419200 ; Expire
604800 ) ; Negative Cache TTL
starc.rk. IN NS ns1.starc.rk.
ns1 IN A 192.168.1.1
ns2 IN A 192.168.1.2
www IN CNAME ns1
EOF
Pricakovan output
Pricakovan output
; <<>> DiG 9.16.15-Ubuntu <<>> ns1.starc.rk @localhost
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 61062
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
; COOKIE: bd4731d203abd769010000006281894b1a3dca4204c62136 (good)
;; QUESTION SECTION:
;ns1.starc.rk. IN A
;; ANSWER SECTION:
ns1.starc.rk. 604800 IN A 192.168.1.1
;; Query time: 3 msec
;; SERVER: ::1#53(::1)
;; WHEN: Sun May 15 23:14:19 UTC 2022
;; MSG SIZE rcvd: 85
Za nas je pomembno, da dobimo veljaven odgovor, ki nam pove, da ns1.starc.rk je ekvivalenten ipv4 192.168.1.1.
Reverse DNS¶
Reverse-dns bomo nastavili za cono 1.168.192.in-addr.arpa
cat << EOF > /etc/bind/db.1.168.192.in-addr.arpa
; 1.168.192.in-addr.arpa
\$TTL 604800
1.168.192.in-addr.arpa. IN SOA ns1.starc.rk. hostmaster.starc.rk. (
1 ; Serial
604800 ; Refresh
86400 ; Retry
2419200 ; Expire
604800 ) ; Negative Cache TTL
1.168.192.in-addr.arpa. IN NS ns1.starc.rk.
1 IN PTR ns1.starc.rk.
2 IN PTR ns2.starc.rk.
EOF
Append-amo zone db file import v named.conf.local file
cat << EOF >> /etc/bind/named.conf.local
zone "1.168.192.in-addr.arpa" {
type master;
file "/etc/bind/db.1.168.192.in-addr.arpa";
};
EOF
named-checkzone 1.168.192.in-addr.arpa /etc/bind/db.1.168.192.in-addr.arpa
service named restart
dig 1.1.168.192.in-addr.arpa @localhost PTR
Client1 use local DNS¶
Secondary DNS server¶
Nastavimo permission-e za /etc/bind folder, da bo lahko uporabnik, ki ga bind server uporablja (da lahko pozneje v koraku Reverse DNS prenese in zapise datoteko, ko jo prenese iz DNS1).
Own domain¶
Vstavimo konfiguracijo za slave-server
cat << EOF >> /etc/bind/named.conf.local
zone "starc.rk" {
type slave;
file "/etc/bind/db.rk.starc-slave";
masterfile-format text;
masters {
192.168.1.1;
};
};
EOF
Zajem prometa
Pred naslednjim korakom zaženemo zajem prometa na povezavi SW <> DNS2 in spremljamo dogajanje.
Zajem prometa shranimo v datoteko dns-transfer.pcapng
Startamo zajem prometa, restartamo named service na DNS2 ter oddamo zahtevo za refresh za cono starc.rk na DNS2.
Pocakamo da se prenos konca in zajem prometa shranimo v export-file imenovan dns-transfer.pcapng.
Reverse DNS¶
Na DNS2 samo definiramo slave-config, saj bo zapis cone (tak kot smo ga zapisali na DNS1) v poznejsem koraku samodejno prenesen iz DNS1 na DNS2.
cat << EOF >> /etc/bind/named.conf.local
zone "1.168.192.in-addr.arpa" {
type slave;
file "/etc/bind/db.1.168.192.in-addr.arpa-slave";
masterfile-format text;
masters {
192.168.1.1;
};
};
EOF
Sedaj pocakaj par sekund, saj ukaz rndc refresh doda zahtevo za prenos z queue in zato Ko je prenos izveden, v terminalu prikazemo vsebino datoteke /etc/bind/db.1.168.192.in-addr.arpa-slave ter zajamemo screenshot terminala v datoteko imenovano db.1.168.192.in-addr.arpa-slave.png
Pricakovan izpis je enak vsebini datoteke v prvem koraku v Reverse DNS sekciji.
Wrapping up¶
Koncno smo koncali nalogo. Datoteki dns-transfer.pcapng ter db.1.168.192.in-addr.arpa-slave.png za-zipp-aj v datoteko VPISNA_STEVILKA.zip (kjer je VPISNA_STEVILKA tvoja lastna vpisna stevilka).
Zip file oddaj na eucilnico.