All MIBs › JUNIPER-JS-SCREENING-MIB › jnxJsScreenMonTcpSynFin
jnxJsScreenMonTcpSynFin
Module: JUNIPER-JS-SCREENING-MIB
OID (symbolic): JUNIPER-JS-SCREENING-MIB::jnxJsScreenMonTcpSynFin
OID (numeric): 1.3.6.1.4.1.2636.3.39.1.8.1.1.1.1.26
Node type: OBJECT-TYPE
Type: Counter64
Access: read-only
Description: Both the SYN and FIN control flags are not normally set in the same TCP segment header. The SYN flag synchronizes sequence numbers to initiate a TCP connection. The FIN flag indicates the end of data transmission to finish a TCP connection. Their purposes are mutually exclusive. A TCP header with the SYN and FIN flags set is anomalous TCP behavior, causing various responses from the recipient, depending on the OS.
When block both syn and fin option is enable, the device drops the packet when it discovers such a header
This attribute records the TCP syn fin both set packet dropped.
What is jnxJsScreenMonTcpSynFin?
This read-only counter tallies TCP packets dropped in this zone that have both the SYN and FIN flags set simultaneously, a combination that's mutually exclusive in normal TCP behavior and typically indicates OS-fingerprinting or evasion traffic. An admin watching this counter climb knows the device is blocking this specific anomalous TCP flag combination.
Examples
Walk all instances (SNMPv2c):
snmpwalk -v2c -c public <target> 1.3.6.1.4.1.2636.3.39.1.8.1.1.1.1.26 snmpwalk -v2c -c public <target> JUNIPER-JS-SCREENING-MIB::jnxJsScreenMonTcpSynFin
Get a specific instance (index 1):
snmpget -v2c -c public <target> 1.3.6.1.4.1.2636.3.39.1.8.1.1.1.1.26.1 snmpget -v2c -c public <target> JUNIPER-JS-SCREENING-MIB::jnxJsScreenMonTcpSynFin.1
SNMPv3 example:
snmpget -v3 -l authPriv -u snmpv3-user -a SHA -A "AuthPassword1" -x AES -X "PrivPassword1" <target> jnxJsScreenMonTcpSynFin.1
Start monitoring Juniper SRX/J-series security appliance (DoS/DDoS screen defenses) with a free 30-day trial of IPNetwork Monitor. Create custom SNMP monitor using the JUNIPER-JS-SCREENING-MIB::jnxJsScreenMonTcpSynFin OID value, configure state conditions and alerts, and monitor any Juniper SRX/J-series security appliance (DoS/DDoS screen defenses) from a single console.
OID Breakdown
Upper-level ancestors (11 from the standard OID tree / other modules)
| Numeric OID | Name | Module |
|---|---|---|
| 1 | iso | LANART-AGENT |
| 1.3 | org | AirPair-MIB |
| 1.3.6 | dod | AirPair-MIB |
| 1.3.6.1 | internet | AirPair-MIB |
| 1.3.6.1.4 | private | AirPair-MIB |
| 1.3.6.1.4.1 | enterprises | AirPair-MIB |
| 1.3.6.1.4.1.2636 | juniperMIB | JUNIPER-SMI |
| 1.3.6.1.4.1.2636.3 | jnxMibs | JUNIPER-SMI |
| 1.3.6.1.4.1.2636.3.39 | jnxJsMibRoot | JUNIPER-SMI |
| 1.3.6.1.4.1.2636.3.39.1 | jnxJsSecurity | JUNIPER-JS-SMI |
| 1.3.6.1.4.1.2636.3.39.1.8 | jnxJsScreening | JUNIPER-JS-SMI |
| Numeric OID | Name | Module |
|---|---|---|
| 1.3.6.1.4.1.2636.3.39.1.8.1 | jnxJsScreenMIB | JUNIPER-JS-SCREENING-MIB |
| 1.3.6.1.4.1.2636.3.39.1.8.1.1 | jnxJsScreenObjects | JUNIPER-JS-SCREENING-MIB |
| 1.3.6.1.4.1.2636.3.39.1.8.1.1.1 | jnxJsScreenMonTable | JUNIPER-JS-SCREENING-MIB |
| 1.3.6.1.4.1.2636.3.39.1.8.1.1.1.1 | jnxJsScreenMonEntry | JUNIPER-JS-SCREENING-MIB |
| 1.3.6.1.4.1.2636.3.39.1.8.1.1.1.1.26 | jnxJsScreenMonTcpSynFin | JUNIPER-JS-SCREENING-MIB |