Dotaz: ako nastavit prava na vpn servery

[jany2]

Pouzivam ovpn server na ktory sa pripaja niekolko klientov. Klienti vyuzivaju sluzbu na servery a tym padom maju povoleny jeden port. Kedze nechcem aby sa klienti videli, tak na ovpn servery v server.conf som pouzil direktivu

client-to-client

Ak potrebujem robit nejake upravy u klienta, tak direktivu zaremujem # a reloadnem server. Vtedy sa klienti vidia a mozem robit upravy u klientov. Ja by som vsak potreboval aby sa jeden klient videl so vsetkymi, ale aby sa ostatny navzajom nevideli.

Zrejme to ide vyriesit aj cez firewall, ale nemam velke skusenosti s iptables, ako amater skor pouzivam ufw. Prip. ak by to bolo mozne nastavit v server.conf na ovpn servery, tak by to bolo mozno jednoduchsie.

Odpovědi

[NN]

Sice jsi to napsal naruby, ale nevadi. Mohlo by stacit vypnout client-to-client a manualne povolit forward pro klienta do celeho subnetu:

ufw allow proto any from 10.0.40.13 to 10.0.40.0/8

50c

[jany2]

jj jasne s tym # som to poplietol (je to opacne), ale bud som ***** alebo to nefunguje.
resetol som si ufw

sudo ufw disable
sudo ufw reset
sudo ufw allow 22
sudo ufw enable

a pridavam postupne pravidla.

sudo ufw allow 22500/tcp

port cez ktory sa pripajaju klienti na server

sudo ufw allow 1194/tcp

povolenie vpn

sudo ufw allow proto any from 10.8.0.153 to 10.8.0.0/24

toto si mi poradil, aby som mal z jednej IP 10.8.0.153 pristupnu celu vpn

sudo ufw deny proto any from 10.8.0.0/24

a celej vpn zakazem pristup vsade.

     Do                         Operácia    Od
     --                         --------    --
[ 1] 22                         ALLOW IN    Anywhere
[ 2] 22500/tcp                  ALLOW IN    Anywhere
[ 3] 1194/tcp                   ALLOW IN    Anywhere
[ 4] 10.8.0.0/24                ALLOW IN    10.8.0.153
[ 5] Anywhere                   DENY IN     10.8.0.0/24

Tato tabulka je vystup ufw. Rozumiem tomu tak, ze pravidlo 4 hovori, ze z IP 10.8.0.153 mam pristupnu siet 10.8.0.0/24 a pravidlo 5 hovori, ze cela 10.8.0.0/24 ma vsetko zakazane. Cize cela 10.8.0.0/24 ma povolene pravidlo 1,2,3 a dalej ma vsetko zakazane.
Ale ja sa aj teraz dokazem z akejkolvek 10.8.0.x pripojit na akykolvek 10.8.0.x cez port 80 (web)

[NN]

Mozna mas allow forward policy.. jak vypada iptables -L -n? V jakem modu routed/bridged bezi VPN?

[jany2]

iptables vypada takto

Chain INPUT (policy DROP)
target     prot opt source               destination         
ufw-before-logging-input  all  --  0.0.0.0/0            0.0.0.0/0           
ufw-before-input  all  --  0.0.0.0/0            0.0.0.0/0           
ufw-after-input  all  --  0.0.0.0/0            0.0.0.0/0           
ufw-after-logging-input  all  --  0.0.0.0/0            0.0.0.0/0           
ufw-reject-input  all  --  0.0.0.0/0            0.0.0.0/0           
ufw-track-input  all  --  0.0.0.0/0            0.0.0.0/0           

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         
ufw-before-logging-forward  all  --  0.0.0.0/0            0.0.0.0/0           
ufw-before-forward  all  --  0.0.0.0/0            0.0.0.0/0           
ufw-after-forward  all  --  0.0.0.0/0            0.0.0.0/0           
ufw-after-logging-forward  all  --  0.0.0.0/0            0.0.0.0/0           
ufw-reject-forward  all  --  0.0.0.0/0            0.0.0.0/0           
ufw-track-forward  all  --  0.0.0.0/0            0.0.0.0/0           

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination         
ufw-before-logging-output  all  --  0.0.0.0/0            0.0.0.0/0           
ufw-before-output  all  --  0.0.0.0/0            0.0.0.0/0           
ufw-after-output  all  --  0.0.0.0/0            0.0.0.0/0           
ufw-after-logging-output  all  --  0.0.0.0/0            0.0.0.0/0           
ufw-reject-output  all  --  0.0.0.0/0            0.0.0.0/0           
ufw-track-output  all  --  0.0.0.0/0            0.0.0.0/0           

Chain ufw-after-forward (1 references)
target     prot opt source               destination         

Chain ufw-after-input (1 references)
target     prot opt source               destination         
ufw-skip-to-policy-input  udp  --  0.0.0.0/0            0.0.0.0/0            udp dpt:137
ufw-skip-to-policy-input  udp  --  0.0.0.0/0            0.0.0.0/0            udp dpt:138
ufw-skip-to-policy-input  tcp  --  0.0.0.0/0            0.0.0.0/0            tcp dpt:139
ufw-skip-to-policy-input  tcp  --  0.0.0.0/0            0.0.0.0/0            tcp dpt:445
ufw-skip-to-policy-input  udp  --  0.0.0.0/0            0.0.0.0/0            udp dpt:67
ufw-skip-to-policy-input  udp  --  0.0.0.0/0            0.0.0.0/0            udp dpt:68
ufw-skip-to-policy-input  all  --  0.0.0.0/0            0.0.0.0/0            ADDRTYPE match dst-type BROADCAST

Chain ufw-after-logging-forward (1 references)
target     prot opt source               destination         

Chain ufw-after-logging-input (1 references)
target     prot opt source               destination         
LOG        all  --  0.0.0.0/0            0.0.0.0/0            limit: avg 3/min burst 10 LOG flags 0 level 4 prefix "[UFW BLOCK] "

Chain ufw-after-logging-output (1 references)
target     prot opt source               destination         

Chain ufw-after-output (1 references)
target     prot opt source               destination         

Chain ufw-before-forward (1 references)
target     prot opt source               destination         
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0            ctstate RELATED,ESTABLISHED
ACCEPT     icmp --  0.0.0.0/0            0.0.0.0/0            icmptype 3
ACCEPT     icmp --  0.0.0.0/0            0.0.0.0/0            icmptype 4
ACCEPT     icmp --  0.0.0.0/0            0.0.0.0/0            icmptype 11
ACCEPT     icmp --  0.0.0.0/0            0.0.0.0/0            icmptype 12
ACCEPT     icmp --  0.0.0.0/0            0.0.0.0/0            icmptype 8
ufw-user-forward  all  --  0.0.0.0/0            0.0.0.0/0           

Chain ufw-before-input (1 references)
target     prot opt source               destination         
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0           
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0            ctstate RELATED,ESTABLISHED
ufw-logging-deny  all  --  0.0.0.0/0            0.0.0.0/0            ctstate INVALID
DROP       all  --  0.0.0.0/0            0.0.0.0/0            ctstate INVALID
ACCEPT     icmp --  0.0.0.0/0            0.0.0.0/0            icmptype 3
ACCEPT     icmp --  0.0.0.0/0            0.0.0.0/0            icmptype 4
ACCEPT     icmp --  0.0.0.0/0            0.0.0.0/0            icmptype 11
ACCEPT     icmp --  0.0.0.0/0            0.0.0.0/0            icmptype 12
ACCEPT     icmp --  0.0.0.0/0            0.0.0.0/0            icmptype 8
ACCEPT     udp  --  0.0.0.0/0            0.0.0.0/0            udp spt:67 dpt:68
ufw-not-local  all  --  0.0.0.0/0            0.0.0.0/0           
ACCEPT     udp  --  0.0.0.0/0            224.0.0.251          udp dpt:5353
ACCEPT     udp  --  0.0.0.0/0            239.255.255.250      udp dpt:1900
ufw-user-input  all  --  0.0.0.0/0            0.0.0.0/0           

Chain ufw-before-logging-forward (1 references)
target     prot opt source               destination         

Chain ufw-before-logging-input (1 references)
target     prot opt source               destination         

Chain ufw-before-logging-output (1 references)
target     prot opt source               destination         

Chain ufw-before-output (1 references)
target     prot opt source               destination         
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0           
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0            ctstate RELATED,ESTABLISHED
ufw-user-output  all  --  0.0.0.0/0            0.0.0.0/0           

Chain ufw-logging-allow (0 references)
target     prot opt source               destination         
LOG        all  --  0.0.0.0/0            0.0.0.0/0            limit: avg 3/min burst 10 LOG flags 0 level 4 prefix "[UFW ALLOW] "

Chain ufw-logging-deny (2 references)
target     prot opt source               destination         
RETURN     all  --  0.0.0.0/0            0.0.0.0/0            ctstate INVALID limit: avg 3/min burst 10
LOG        all  --  0.0.0.0/0            0.0.0.0/0            limit: avg 3/min burst 10 LOG flags 0 level 4 prefix "[UFW BLOCK] "

Chain ufw-not-local (1 references)
target     prot opt source               destination         
RETURN     all  --  0.0.0.0/0            0.0.0.0/0            ADDRTYPE match dst-type LOCAL
RETURN     all  --  0.0.0.0/0            0.0.0.0/0            ADDRTYPE match dst-type MULTICAST
RETURN     all  --  0.0.0.0/0            0.0.0.0/0            ADDRTYPE match dst-type BROADCAST
ufw-logging-deny  all  --  0.0.0.0/0            0.0.0.0/0            limit: avg 3/min burst 10
DROP       all  --  0.0.0.0/0            0.0.0.0/0           

Chain ufw-reject-forward (1 references)
target     prot opt source               destination         

Chain ufw-reject-input (1 references)
target     prot opt source               destination         

Chain ufw-reject-output (1 references)
target     prot opt source               destination         

Chain ufw-skip-to-policy-forward (0 references)
target     prot opt source               destination         
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0           

Chain ufw-skip-to-policy-input (7 references)
target     prot opt source               destination         
DROP       all  --  0.0.0.0/0            0.0.0.0/0           

Chain ufw-skip-to-policy-output (0 references)
target     prot opt source               destination         
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0           

Chain ufw-track-forward (1 references)
target     prot opt source               destination         
ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0            ctstate NEW
ACCEPT     udp  --  0.0.0.0/0            0.0.0.0/0            ctstate NEW

Chain ufw-track-input (1 references)
target     prot opt source               destination         

Chain ufw-track-output (1 references)
target     prot opt source               destination         
ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0            ctstate NEW
ACCEPT     udp  --  0.0.0.0/0            0.0.0.0/0            ctstate NEW

Chain ufw-user-forward (1 references)
target     prot opt source               destination         

Chain ufw-user-input (1 references)
target     prot opt source               destination         
ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0            tcp dpt:22
ACCEPT     udp  --  0.0.0.0/0            0.0.0.0/0            udp dpt:22
ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0            tcp dpt:22500
ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0            tcp dpt:1194
ACCEPT     all  --  10.8.0.153           10.8.0.0/24         
DROP       all  --  10.8.0.0/24          0.0.0.0/0           

Chain ufw-user-limit (0 references)
target     prot opt source               destination         
LOG        all  --  0.0.0.0/0            0.0.0.0/0            limit: avg 3/min burst 5 LOG flags 0 level 4 prefix "[UFW LIMIT BLOCK] "
REJECT     all  --  0.0.0.0/0            0.0.0.0/0            reject-with icmp-port-unreachable

Chain ufw-user-limit-accept (0 references)
target     prot opt source               destination         
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0           

Chain ufw-user-logging-forward (0 references)
target     prot opt source               destination         

Chain ufw-user-logging-input (0 references)
target     prot opt source               destination         

Chain ufw-user-logging-output (0 references)
target     prot opt source               destination         

Chain ufw-user-output (1 references)
target     prot opt source               destination         

VPN bezi v bridge (v /etc/sysctl.conf mam zakomentovany #net.ipv4.ip_forward=1 pretoze vpn ma na severy koncit, nema smerovat klientov skrz)

[NN]

Wait what? K cemu ta VPN slouzi, kdyz a klienti nekomunikuji ani dal ani mezi sebou?

[jany2]

Komunikuju s jednou aplikaciou na servery

[NN]

Rekl bych, ze to nefunguje proto, ze pravidla se zapsala to inputu, ale pakety se vraci na tap. Takze vzhledem k politice forward by jsi potreboval neco jako:

iptables -A FORWARD -i tap0 -s 10.0.x.x -o tap0 -d 10.0.x.x./24 -j ACCEPT
iptables -A FORWARD -i tap0 -o tap0 -j DROP

Jak se to zapisuje v ufw nevim. Jak se to bude chovat na bridged rozhrani si nejsem jisty. ;)

[jany2]

Mozno je to na smiech, ale ja som si vytvoril v ufw pravidla takto

[ 1] 22                         ALLOW IN    Anywhere
[ 2] 22500/tcp                  ALLOW IN    Anywhere
[ 3] 21                         DENY IN     10.8.0.0/24
[ 4] 21/tcp                     ALLOW IN    Anywhere
[ 5] 80                         DENY IN     10.8.0.0/24
[ 6] 80/tcp                     ALLOW IN    Anywhere
[ 7] 10000                      DENY IN     10.8.0.0/24
[ 8] 10000/tcp                  ALLOW IN    Anywhere
[ 9] 9981                       DENY IN     10.8.0.0/24
[10] 9981/tcp                   ALLOW IN    Anywhere
[11] 9091                       DENY IN     10.8.0.0/24
[12] 9091/tcp                   ALLOW IN    Anywhere
[13] 443                        DENY IN     10.8.0.0/24
[14] 443                        ALLOW IN    Anywhere

A je to myslene takto: port 22500 je povoleny pre vsetkych. Port 21 (ftp) ma zakazany vpn subnet 10.8.0.0/24 a ostatny ho maju povoleny, port 80 deto atd .... Tym som chcel zabranit, aby vpn klienti mali pristup k sluzbam, ktore su v LAN sieti (pristup maju len na port 22500 a 22 (na 22 nic nezmozu)). Takto to funguje dobre. Mozno sa to da aj jednoduchsie, ale neprisiel som na to.
Navrtal si mi do hlavy chrobaka, ze jedno pravidlo nastavit tak, aby jedna ip vo vpn mala pristup k celej vpn 10.8.0.0/24 ale nejak to nefunguje. Pomoze mi len edit /etc/openvpn/server.conf a odkomentovat client to client, vtedy sa ale vidia vsetci klienti (to mi az tak nevadi, ale mam robotu navyse odkomentovavavt to a reloadovat openvpn)