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Archivio: openbsd@sikurezza.org Soggetto: Re: PF Help! Mittente: dario billo Data: 12 Apr 2003 19:12:35 -0000
Non va perchè dovrebbe "uscire e rientrare" :-) metti nel file hosts dei client interni l'indirizzo ed il relativo nome di ogni server. Il problema è dato dal fatto che la procedura di connessione non gli torna. Di solito è così: - il client richiede al dns l'ip del server http a cui si deve collegare - il dns restituisce al client l'ip - il client si collega nel tuo caso succede invece questo: - il client richiede al dns l'ip del server http a cui si deve collegare - il dns restituisce al client l'ip (x es 1.2.3.4) - il client prova a collegarsi all'ip, che poi altro non è che l'if esterna del tuo gw, e fa uscire la connessione attraverso il gw. In sostanza, le cose dovrebbero essere 2: 1 - O il dns ti restituisce l'ip interno alla rete (impossibile) 2 - O metti l'ip del server nel file hosts. Tale file viene letto (di solito) prima di un'interrrogazione a dns, quindi il tuo sys sa dove andare a trovare il server nella lan So che mi sono spiegato da cani, ma se lo fai risolvi il problema. Ciao agorin@tin.it wrote: >Chiedo lumi a goony, o a chiunque mi possa aiutare, relativamente a un problema >che non riesco a risolvere... > >In altre parole non ne vengo fuori. > >Ho installato un firewall PF - OPENBSD 3.2 ad un amico che ha dei siti web >"in casa". Ho recuperato in giro un po' di esempi e comandi e la cosa sembrava >funzionare >(non sono un esperto di PF ne' di networking)... C'è un unico grande problema: >non riesce a vedere i "propri" siti! Riesce a navigare (il natting funziona), >i siti interni vengono visti dall'esterno, ma non ha visibilità dei siti >interni! > >Non capisco il perchè... Ti allego lo script... Per favore, datemi una mano... > >Vi ringrazio già da ora ! > >P.S.: Al Webbit ci sarò sicuramente e seguiro i talk su OPENBSD (La prima >copia l'avevo acquiestata l'anno scorso durante la manifestazione!). > >Ecco il PF.CONF (gli indirizzi sono fittizzi): > ># ># Interface: ># lo0 - loopback ># rl0 - external to router (INTERNET) ># rl1 - internal to private network ># ># Filtering policy ordering: ># + Block everything unless there are permit (pass) rules ># - Permit all loopback packets to flow freely ># - Permit all internal network packets to flow freely ># - Permit individual type of service to flow freely to outside world: ># ftp ># smtp ># whois ># dns ># http/https ># pop3 ># traceroute ># ping ># dhclient ># + Since there are no permit(pass) rules at this stage, everything ># else is blocked! ># ># share and enjoy, ># ># hoang@muine.org ># July 9, 2002 ># > ># --------------------------------------------------------------------------- ># Declare interfaces ># --------------------------------------------------------------------------- >LoIf="lo0" >ExtIf="rl0" >IntIf="rl1" > ># --------------------------------------------------------------------------- ># Web server IP address (internal) ># --------------------------------------------------------------------------- >WWWIP="10.x.x.20/32" > ># --------------------------------------------------------------------------- ># Firewall IP address (external) ># --------------------------------------------------------------------------- >FRWL="80.x.x.1/32" > ># --------------------------------------------------------------------------- ># Clients (internal) ># --------------------------------------------------------------------------- >PC1="10.x.x.10/32" > ># --------------------------------------------------------------------------- ># --------------------------------------------------------------------------- ># Interface: all ># Resolve overlapping IP fragments. Fragments are cached and reassembled >by ># pf before a packet is received by its destinations. This will protect > ># machines with less secure stacks behind it from fragmentation attacks. ># --------------------------------------------------------------------------- >scrub in all > ># --------------------------------------------------------------------------- ># Natting and redirection rules. ># --------------------------------------------------------------------------- >nat on rl0 from 10.x.x.20/32 to any -> 80.x.x.2 >nat on rl0 from 10.x.x.0/8 to any -> 80.x.x.1 > >rdr on rl0 proto tcp from any to 80.x.x.2/32 port 80 -> 10.x.x.20 port >80 >rdr on rl0 proto tcp from any to 80.x.x.2/32 port 21 -> 10.x.x.20 port >21 > ># +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ># Interface: all ># Block all incoming and outgoing packets unless they're allowed later. ># +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >block in log all >block out log all > ># --------------------------------------------------------------------------- ># Interface: $LoIf ># Allow loopback to flow freely. ># --------------------------------------------------------------------------- >pass in quick on $LoIf all >pass out quick on $LoIf all ># --------------------------------------------------------------------------- > ># --------------------------------------------------------------------------- ># Interface: $IntIf ># Allow internal traffic to flow freely. ># --------------------------------------------------------------------------- >pass in quick on $IntIf all >pass out quick on $IntIf all ># --------------------------------------------------------------------------- > ># --------------------------------------------------------------------------- ># Interface: $ExtIf ># Allow _internal_ and fw initiated connections from hosts behind NAT to > ># outside world. ># --------------------------------------------------------------------------- ># [passive ftp client to outside world step 1] >pass out quick on $ExtIf proto tcp from any to any port = 21 flags S keep >state ># [telnet to outside world] >pass out quick on $ExtIf proto tcp from any to any port = 23 flags S keep >state ># [smtp to outside world] >pass out quick on $ExtIf proto tcp from any to any port = 25 flags S keep >state ># [whois to outside world] >pass out quick on $ExtIf proto tcp from any to any port = 43 flags S keep >state ># [domain to outside world] >pass out quick on $ExtIf proto tcp from any to any port = 53 flags S keep >state >pass out quick on $ExtIf proto udp from any to any port = 53 keep state > ># [http to outside world] >pass out quick on $ExtIf proto tcp from any to any port = 80 flags S keep >state ># [pop3 to outside world] >pass out quick on $ExtIf proto tcp from any to any port = 110 flags S keep >state ># [https to outside world] >pass out quick on $ExtIf proto tcp from any to any port = 443 flags S keep >state ># [passive ftp to outside world step 2 where the FTP server decides which >port ># for ftp data back] >pass out quick on $ExtIf proto tcp from any to any port > 1023 flags S keep >state ># [traceroute to outside world 1st stage: probing...man traceroute(8)] >pass out quick on $ExtIf proto udp from any to any port 33434 >< 33525 keep >state ># [ping to outside world] >pass out quick on $ExtIf proto icmp from any to any keep state ># [dialpad and probably others require opening high udp ports] >pass out quick on $ExtIf proto udp from any to any keep state ># --------------------------------------------------------------------------- ># Allow _external_ initiated connections from outside world to hosts behind ># NAT and fw. ># --------------------------------------------------------------------------- ># [bootpc to fw] >pass in quick on $ExtIf proto udp from any to any port = 68 keep state ># [traceroute to internal host 2nd stage: receiving error code of icmp-type >3 ># (destination unreachable) and icmp-type 11 (time exceeded)] >pass in quick on $ExtIf inet proto icmp from any to any icmp-type 3 keep >state >pass in quick on $ExtIf inet proto icmp from any to any icmp-type 11 keep >state ># [active ftp] >pass in quick on $ExtIf proto tcp from any to $ExtIf port > 49151 flags >S keep state > ># +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ># Interface: $ExtIf ># Since there are no permit(pass) rules at this stage, everything else is > ># blocked as last matching rules apply. ># +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > ># +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ># Andrea: ># +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ># ># Impostazioni WWW: ># >pass in quick on $ExtIf inet proto tcp from any to $WWWIP port=80 keep state > >pass out quick on $ExtIf inet proto tcp from $WWWIP port=80 to any keep >state ># ># Impostazioni FTP: ># >pass in quick on $ExtIf inet proto tcp from any to $WWWIP port=21 keep state >pass out quick on $ExtIf inet proto tcp from $WWWIP port=21 to any keep >state ># ># Impostazioni SSH lato Internet: ># >pass in quick on $ExtIf inet proto tcp from any to $FRWL port=22 keep state >pass out quick on $ExtIf inet proto tcp from $FRWL port=22 to any keep state ># ># +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > >________________________________________________________ >http://www.sikurezza.org - Italian Security Mailing List > > > > > ________________________________________________________ http://www.sikurezza.org - Italian Security Mailing List
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