Tag Archives: iptables

Filtering/sanitizing IP addresses lists on command line

Sometimes You have to obtain via command line on a list of IP addresses and you need to be sure it will not contain any IP addresses assigned to the machine You’re working on – especially, when You’re planning to use this list during automated modification of firewall rules.

Seeing strange UDP connections to

Today the CSF firewall on one of our servers controlled by DirectAdmin started showing blocked outgoing UDP connections to on ports 25, 80 and 443. kernel: Firewall: *UDP_OUT Blocked* IN= OUT=eth0 SRC=X.X.X.X \ DST= LEN=1421 TOS=0x00 PREC=0x00 TTL=64 ID=12594 \ DF PROTO=UDP SPT=39792 DPT=80 LEN=1401 kernel: Firewall: *UDP_OUT Blocked* IN= OUT=eth0 SRC=X.X.X.X \ DST= Read the full article…

ConfigServer Security & Firewall (CSF) issue with natting to a remote PPTP server

One of my networks is protected by CSF, running on the router, and I noticed, I’m not able to connect from this network to a remote PPTP server (in this case it’s Poptop), while connecting from other networks, to the same PPTP server, is possible without problems. [me]—-[router with CSF]—-[Internet]—-[Poptop server] Of course the solution Read the full article…