Dotaz: Nastaveni routovani a FW

[polo23]

Ahoj, potreboval bych pomoct s nastavenim routovani s FW na serveru a klientske stanici. Zapojeni je nasledujici.

[client] -----openvpn----> [VPS server] -----> [internet]

O co mi jde... Chtel bych se na web server napr. seznam.cz pripojovat pres muj VPS server, na ktery jsem pripojeny pres openvpn. Jak client tak VPS server jsou Debian Squeeze.

Zatim dokazu pingnout z clienta pres openvpn na VPS server. Kdyz chci pingnout na seznam.cz tak se pakety dostanou pres openvpn na VPS server a odesilaji se na seznam.cz, ale nevraci se zpet (zjisteno tcpdumpem). Na VPS serveru mam docasne vypnuty FW

KONFIGURACE CLENTA

ip a

1: lo: LOOPBACK,UP,LOWER_UP mtu 16436 qdisc noqueue state UNKNOWN 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: BROADCAST,MULTICAST,UP,LOWER_UP mtu 1500 qdisc mq master br0 state UP qlen 1000
    link/ether 00:1c:25:95:20:bd brd ff:ff:ff:ff:ff:ff
    inet6 fe80::21c:25ff:fe95:20bd/64 scope link 
       valid_lft forever preferred_lft forever
3: wlan0: BROADCAST,MULTICAST mtu 1500 qdisc noop state DOWN qlen 1000
    link/ether 00:16:ea:bb:bd:54 brd ff:ff:ff:ff:ff:ff
4: br0: BROADCAST,MULTICAST,UP,LOWER_UP mtu 1500 qdisc noqueue state UP 
    link/ether 00:1c:25:95:20:bd brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.254/24 brd 192.168.1.255 scope global br0
    inet6 fe80::21c:25ff:fe95:20bd/64 scope link 
       valid_lft forever preferred_lft forever
10: tun0: POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 100
    link/none 
    inet 10.1.1.2 peer 10.1.1.1/32 scope global tun0

ip ro

default via 192.168.1.1 dev br0 
10.1.1.1 dev tun0  proto kernel  scope link  src 10.1.1.2 
77.75.72.3 via 10.1.1.2 dev tun0 
169.254.0.0/16 dev br0  scope link  metric 1000 
192.168.1.0/24 dev br0  proto kernel  scope link  src 192.168.1.254

iptables -L -n -v

Chain INPUT (policy ACCEPT 4567K packets, 5268M bytes)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 fail2ban-ssh  tcp  --  *      *       0.0.0.0/0            0.0.0.0/0           multiport dports 2345 

Chain FORWARD (policy ACCEPT 37614 packets, 38M bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain OUTPUT (policy ACCEPT 4335K packets, 3088M bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain fail2ban-ssh (1 references)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 RETURN     all  --  *      *       0.0.0.0/0            0.0.0.0/0

KONFIGURACE VPS SERVERU

ip a

1: lo: LOOPBACK,UP,LOWER_UP mtu 16436 qdisc noqueue state UNKNOWN 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: venet0: BROADCAST,POINTOPOINT,NOARP,UP,LOWER_UP mtu 1500 qdisc noqueue state UNKNOWN 
    link/void 
    inet 93.185.106.99/32 scope global venet0
3: tun0: POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 100
    link/[65534] 
    inet 10.1.1.1 peer 10.1.1.2/32 scope global tun0

ip ro

191.255.255.1 dev venet0  scope link 
10.1.1.2 dev tun0  proto kernel  scope link  src 10.1.1.1 
default via 191.255.255.1 dev venet0 

iptables -L -n -v

Chain INPUT (policy ACCEPT 1 packets, 100 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain fail2ban-ssh (0 references)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 RETURN     all  --  *      *       0.0.0.0/0            0.0.0.0/0  

Kdyz na clientu pustim ping 77.75.72.3 (seznam.cz)

Na VPS serveru ukazuje tcpdump nasledujici:

tcpdump -i tun0 icmp

tcpdump: WARNING: arptype 65534 not supported by libpcap - falling back to cooked socket
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on tun0, link-type LINUX_SLL (Linux cooked), capture size 96 bytes
21:04:30.568535 IP 10.1.1.2 > www.seznam.cz: ICMP echo request, id 22483, seq 9, length 64
21:04:31.576253 IP 10.1.1.2 > www.seznam.cz: ICMP echo request, id 22483, seq 10, length 64
21:04:32.583787 IP 10.1.1.2 > www.seznam.cz: ICMP echo request, id 22483, seq 11, length 64
21:04:33.591362 IP 10.1.1.2 > www.seznam.cz: ICMP echo request, id 22483, seq 12, length 64
21:04:34.599161 IP 10.1.1.2 > www.seznam.cz: ICMP echo request, id 22483, seq 13, length 64
21:04:35.607347 IP 10.1.1.2 > www.seznam.cz: ICMP echo request, id 22483, seq 14, length 64

Ping odchazi z klienta na seznam.cz, ale nevraci se zpet...

Odpovědi

[tomk]

Ahoj, NATuje nekdo ty packety se zdrojovou adresou 10.1.1.2 odchazejici rozhranim venet0 z VPS serveru? Pokud ne, tak s touhle adresou proste odejdou a bud je zahodi hned poskytovatel pripojeni, nebo seznam, v nejhorsim pripade na ne seznam i odpovi, ale sanci dorazit zpet na VPS server, nebo na domaci pocitac stejne nemaji.

Chtelo by to tedy na VPS pravidlo do tabulky nat, ktere udela SNAT pro takovehle packety.

Tomas

[polo23]

Cau, diky za nakopnuti, na NAT jsem uplne zapomnel...

Bohuzel jsem narazil na problem se kterym jsem se setkal uz drive a nevim jak ho poresit. Jde o pridani pravidla do FW.

/sbin/iptables -t nat -A POSTROUTING -o venet0 -j MASQUERADE
FATAL: Could not load /lib/modules/2.6.32/modules.dep: No such file or directory
iptables v1.4.2: can't initialize iptables table `nat': Table does not exist (do you need to insmod?)
Perhaps iptables or your kernel needs to be upgraded.

Nevim jak dostat svepomoci do systemu potrebne moduly, adresar /lib/modules je prazdny.

[tomk]

Pokud je to virtual typu OpenVZ u pipni.cz, nebo neco podobneho, tak tam ma maji jednotlive containery sdilene jadro s nosnym systemem. Modul pro NAT by tedy musel byt nahrany v jadre hostingoveho serveru. Obavam se, ze bude potreba se obratit na provozovatele hostingu.

Tomas

[polo23]

Jo presne, je to pipni.cz a asi to bude to OpenVZ. Diky za info.