ufw blocking apt and dns

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You need to add the following into iptables, as ufw just interfaces with it.

iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

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Fleshgrinder
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Fleshgrinder

Currently working at HelloFresh as staff engineer. See some of my projects over at GitHub.

Updated on September 18, 2022

Comments

  • Fleshgrinder
    Fleshgrinder over 1 year

    I installed ufw on my Debian system like the following:

    # aptitude install ufw
    # ufw limit 22
    # ufw allow 80
    # ufw allow 443
    # ufw enable
    # ufw status verbose
    Status: active
    Logging: on (low)
    Default: deny (incoming), allow (outgoing)
    New profiles: skip
    
    To                         Action      From
    --                         ------      ----
    20                         LIMIT       Anywhere
    80                         ALLOW       Anywhere
    443                        ALLOW       Anywhere
    

    A simple ping google.com fails, also any aptitude install will fail. I searched serverfault for answers. One solution was to allow port 53 for DNS - didn't help. Or ufw allow out 1024:65535/udp together with port 53 - didn't help.

    What worked was to allow my DNS server like ufw allow from [DNS IP]; but that's no solution if you ask me.

    apt-get and aptitude are all blocked by ufw. Couldn't find anything on how to allow installing new things. A ufw log entry example:

    Aug 12 17:31:08 host kernel: [535454.665168] [UFW BLOCK] IN=eth0 OUT= MAC=00:00:00:00:00:00:00:00:00:00:00:00:00:00 SRC=0.0.0.0 DST=0.0.0.0 LEN=60 TOS=0x00 PREC=0x00 TTL=52 ID=0 DF PROTO=TCP SPT=80 DPT=41343 WINDOW=14480 RES=0x00 ACK SYN URGP=0

    Any ideas?

    • Fleshgrinder
      Fleshgrinder almost 12 years
      Is it voted down because the person who voted my question down doesn't know the answer?
    • tacotuesday
      tacotuesday almost 12 years
      I'd look for something like this, since it just interfaces with iptables: iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
    • Fleshgrinder
      Fleshgrinder over 11 years
      @nojak Post it as an answer and I accept it as the correct one. This works like a charm!
    • tacotuesday
      tacotuesday over 11 years
      Glad to hear it!
    • rugk
      rugk about 7 years
      As for DNS, also see UFW is blocking DNS. It might help.
  • Razick
    Razick about 10 years
    This is the first answer after hours of searching to fix the issue. Thanks.