reverse dns is totally broken (debian)

Discussion in 'HOWTO-Related Questions' started by adam, Aug 28, 2006.

  1. adam

    adam New Member

    I used the debian perfect setup and had it running for a week with no problems. (with bind9 installed)

    I've been trying to test the webmail system from vhcs2 and am unsure when the problem arouse. First tests, I was sending out email from the my system to the outside world just fine. Then i signed up at and set up my nameservers there instead of using my server.

    The email stopped working , i coudlnt send out to the world only internally.

    i soon discovered that the dns is not working and i can't downloading anything or use ping etc. I've got no idea what i've broken or how to get it back, ive spent all day looking for info on it.

    my /etc/hosts config looks correct and my /etc/resolv.conf is exactly as the it was in the guide.

    can anyone please help?
  2. adam

    adam New Member

    I disabled the firewall but I don't know why that has stopped it from working. does anyone know what I might have done in shorewall to stop dns lookup from happening?
  3. adam

    adam New Member

    ok, after searching the firewall log i see it's rejecting my packets on numerous ports..

    first it was UDP, SPT=32780, DPT = 53

    and when i enabled those ports in the rules I could ping.

    But now when i try apt-get it now can't resolve and it says it's blocking on

    UDP, SPT=32781, DPT = 53

    can anyone tell me whats going on here and why this was a problem yesterday and not last week?
  4. falko

    falko Super Moderator ISPConfig Developer

    What's in your mail log?
    What's in /etc/resolv.conf? What's the output of
    iptables -L
  5. adam

    adam New Member

    the mail log says its unable to resolve the ip address.

    in my shorewall firewall rules i have
    accept net fw icmp 8
    accept fw net icmp
    accept net fw tcp www,https,smtp,pop3,pop3s,imap2,imaps,submission
    accept net fw udp https
    iptables -L shows
    Chain INPUT
    tcp -- anywhere anywhere tcp dpt:smtp
    tcp -- anywhere anywhere tcp dpt:imap2
    tcp -- anywhere anywhere tcp dpt:pop3
    tcp -- anywhere anywhere tcp dpt:wwall
    all-- anywhere anywhere

    which is repeated again and then the same is show under Chain OUTPUT

    i mean, obviously I have to have something open in my firewall because resolving appears to be blocked as soon as i enable shorewall.
  6. falko

    falko Super Moderator ISPConfig Developer

    What are the exact messages from your mail log? What's in /etc/resolv.conf?
  7. adam

    adam New Member

    the resovl.conf reads exactly as stated in your guide.

    the exact message is no longer in the log because i've reinstalled the system and not put a firewall back on yet.

    The DNS is fine, when i took off the firewall completely I didn't get any problems with it anymore. it seems that shorewall was blocking it, yet im completely unsure as to why because its set up the same way as all the other linux distros ive got.

    like i said above, if i added ports to it as described in the firewall log then things worked until it complained about a different port.

    you can close this thread if you wish because at the moment I cannot test it further because i have scrapped it. When i come to putting on the firewall again I will see if its an issue.

    right now im still wasting my life on this smtp problem. the joys of linux *sigh* :D

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