Debian – ufw blocking apt and dns

aptitudedebiandomain-name-systemfirewallufw

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?

Best Answer

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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