This topic describes how to configure detection of a
TCP port scan attack.
A port scan occurs when one source IP address sends an IP packet
containing TCP SYN segments to a defined number of different ports
at the same destination IP address within a defined interval.
To enable detection of a TCP port scan attack:
- Configure interfaces and assign an IP address to interfaces.
[edit]
user@host# set interfaces ge-0/0/1 unit 0 family inet address 192.0.2.0/24
user@host# set interfaces ge-0/0/3 unit 0 family inet address 198.51.100.0/24
- Configure security zones
trustZone and untrustZone and assign interfaces to them.[edit]
user@host# set security zones security-zone trustZone host-inbound-traffic system-services all
user@host# set security zones security-zone trustZone host-inbound-traffic protocols all
user@host# set security zones security-zone trustZone interfaces ge-0/0/1.0
user@host# set security zones security-zone untrustZone host-inbound-traffic system-services all
user@host# set security zones security-zone untrustZone host-inbound-traffic protocols all
user@host# set security zones security-zone untrustZone interfaces ge-0/0/3.0
- Configure security policies from
untrustZone to trustZone.[edit]
user@host# set security policies from-zone untrustZone to-zone trustZone policy policy1 match source-address any
user@host# set security policies from-zone untrustZone to-zone trustZone policy policy1 match destination-address any
user@host# set security policies from-zone untrustZone to-zone trustZone policy policy1 match application any
user@host# set security policies from-zone untrustZone to-zone trustZone policy policy1 then permit
user@host# set security policies default-policy deny-all
- Configure security screens and attach them to
untrustZone.[edit]
user@host# set security screen ids-option untrustScreen tcp port-scan
user@host# set security screen ids-option untrustScreen alarm-without-drop
user@host# set security zones security-zone untrustZone screen untrustScreen
- Configure syslog.
[edit]
user@host# set system syslog file syslog any any
user@host# set system syslog file syslog archive size 10000000
user@host# set system syslog file syslog structured-data
user@host# set security policies from-zone untrustZone to-zone trustZone policy policy1 then log session-init
user@host# set security policies from-zone untrustZone to-zone trustZone policy policy1 then log session-close
- Commit the configuration.
