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
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