Score:1

ufw log: lots of block action from intranet

us flag

For my "homelab/linux playground" server (lubunut 20.04) I enabled ufw to limit access to ssh for now to intranet. I looked at the ufw logs and see that I'm getting a lot of similar blocking entries like these:

SRC=192.168.0.52 DST=224.0.0.251 LEN=32 TOS=0x00 PREC=0xC0 TTL=1 ID=0 DF PROTO=2 
SRC=192.168.0.1 DST=224.0.0.1 LEN=32 TOS=0x00 PREC=0xC0 TTL=1 ID=54096 PROTO=2 

I clipped the mac addresses and dates in these entries. What is important is that 0.1 is my gateway, ISP provided modem/router, while 0.52 is a rpi running pihole so my dhcp and dns server.

My question is what exactly is being blocked here? And how can I make it not appear in the logs as it clutters the log from any "real danger"?

hr flag
Related: [What could be the cause for these strange UFW block entries in my syslog?](https://askubuntu.com/questions/278964/what-could-be-the-cause-for-these-strange-ufw-block-entries-in-my-syslog)
Score:0
us flag

According to the link from steeldriver DST=224.0.0.251 is multicast DNS which makes sense as it comes from my dns server. The other one comes from the router and seems to be a common issue with "rented ISP routers".

In that thread there is another link and supposedly simply adding a deny rule explicitly for these 2 will remove them from being logged. eg TIL: explicit deny rules are not logged by ufw.

sudo ufw deny from 192.168.0.1 to 224.0.0.1
sudo ufw deny from 192.168.0.52 to 224.0.0.251
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