IT Security & Network Engineering Knowledge Base

Practical documentation and technical guides on network security, firewalls, Linux systems, monitoring, and automation.
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Check Point – Ive pushed the Wrong Policy

Issue There may be a time where you install the wrong policy onto a Check Point Firewall. This can block your connections, and screw which traffic is allowed through the firewall. Resolution These steps will show you how to remove and reinstall the correct policy via the CLI on the manager (SCS), 1. First of … Read more

PIX to Check Point Sample VPN Configuration

Below provide sample configurations required for building a site to site VPN between a Cisco PIX and a Check Point Firewall.   PIX Configuration (config)#isakmp enable outside (config)#isakmp policy 10 (config-isakmp-policy)# encryption aes-256 (config-isakmp-policy)# hash sha (config-isakmp-policy)# authentication pre-share (config-isakmp-policy)# group 1 (config-isakmp-policy)# lifetime 86400 (config)#isakmp key shabba address 1.1.1.1 netmask 255.255.255.255 no-xauth (config)#access-list ED … Read more

Check Point – Moving Files using SCP

Method 1 Even though this maybe more of an article for the Linux area, the only reason I came across this is trying to move the output of a upgrade_export from my SPLAT box, so hence it being under Firewalls – Check Point. If you keep getting prompted with a password box when trying to … Read more

Linux – Unable to send email using Postfix

Below outlines the issue and resoultion when trying to send email using Postfix. Issue When trying to send an email on my linux platform I get the following error message in my mail.log ?? The IP you’re using to send mail is not authorized 550-5.7.1 to send email directly to our servers.      Please use the … Read more

Check Point – Stealth / Drop Rule

Stealth Rule The first rule in the rule base which prevents access to the firewall itself. Implicit Drop / Clean Up Rule This is added by the firewall at the bottom of the rule base. Its role is to drop any traffic that hasn’t been matched to any of the previous rules.

Check Point – Debugging NAT

In order to debug NAT on a checkpoint we need to obtain information via the following, Set the debugging buffer to 2 KB Enable 2 debugging flags Output your data Then to reset the debugging flags. The commands are, fw ctl debug -buf 2048fw ctl debug xlate srcfw ctl kdebug -f >& /tmp/kdebug.outfw ctl debug … Read more

Check Point – Acronyms

FWM    Firewall Management e.g. the SmartCenter ICA     Internal CA, normally SmartCenter SIC     Secure Internal Communication SCS    Smart Centre Server VTI     Virtual Tunnel Interface (VPNs) MDG    Multi Domain GUI (Provider-1) MDS    Multi Domain Server, Manager or Container (Provider-1) CMA    Customer Management Add-on (Provider-1) – “Smart Center Server” MLM    Multi Customer Log Module (Provider-1) CLM     Customer Log … Read more

UNIX – TCP/IP Stack Modifications

Solaris Prevent DoS /usr/sbin/ndd -set /dev/tcp tcp_conn_req_max_q 1024/usr/sbin/ndd -set /dev/tcp tcp_conn_req_max_q0 2048/usr/sbin/ndd -set /dev/tcp tcp_time_wait_interval 60000/usr/sbin/ndd -set /dev/ip ip_respond_to_echo_broadcast 0/usr/sbin/ndd -set /dev/ip ip_forward_directed_broadcasts 0 Disable redirects /usr/sbin/ndd -set /dev/ip ip_ignore_redirect 1/usr/sbin/ndd -set /dev/ip ip_send_redirects 0 Disable Source routing /usr/sbin/ndd -set /dev/ip ip_forward_src_routed 0 Linux Kernal 2.2 Prevent DoS /sbin/sysctl -w net.ipv4.tcp_max_syn_backlog=1280/sbin/sysctl -w net.ipv4.vs.timeout_timewait=60/sbin/sysctl -w net.ipv4.icmp_echo_ignore_broadcasts=1 … Read more

Check Point – QoS

DiffServ (Differentiated Services)A layer 3 protocol, defined by the IEFT. Used for adding QoS to IP networks. WFRED(Weighted Flow Random Early Drop)A process for managing packet buffers, by dropping packets during periods of network congestion.This is transparent to the user and requires no configuration. IQ (Intelligent Queuing Engine)Using information from the Check Point INSPECT engine … Read more