All MIBs › CHECKPOINT-MIB-2 › ifMtu
ifMtu
Module: CHECKPOINT-MIB-2
OID (symbolic): CHECKPOINT-MIB-2::ifMtu
OID (numeric): 1.3.6.1.2.1.2.2.1.4
Node type: OBJECT-TYPE
Type: INTEGER
Access: read-only
Description: The size of the largest datagram which can be sent/received on the interface, specified in octets. For interfaces that are used for transmitting network datagrams, this is the size of the largest network datagram that can be sent on the interface.
What is ifMtu?
Reports the largest datagram, in octets, the interface can send or receive. Higher-layer protocols and path-MTU-discovery logic rely on this value, so if it's misreported or set wrong for a tunnel or VLAN interface, large packets get silently fragmented or dropped rather than delivered whole. Example: ifMtu reporting 1500 on a physical Ethernet leg but 1400 on a VPN tunnel interface explains why large HTTP responses sent over the tunnel get fragmented while the same traffic on the LAN side doesn't.
Examples
Walk all instances (SNMPv2c):
snmpwalk -v2c -c public <target> 1.3.6.1.2.1.2.2.1.4 snmpwalk -v2c -c public <target> CHECKPOINT-MIB-2::ifMtu
Get a specific instance (index 1):
snmpget -v2c -c public <target> 1.3.6.1.2.1.2.2.1.4.1 snmpget -v2c -c public <target> CHECKPOINT-MIB-2::ifMtu.1
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OID Breakdown
Upper-level ancestors (6 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 |
| 1.3.6.1.2 | mgmt | AXON-MIB |
| 1.3.6.1.2.1 | mib_2 | AXON-MIB |
| Numeric OID | Name | Module |
|---|---|---|
| 1.3.6.1.2.1.2 | interfaces | CHECKPOINT-MIB-2 |
| 1.3.6.1.2.1.2.2 | ifTable | CHECKPOINT-MIB-2 |
| 1.3.6.1.2.1.2.2.1 | ifEntry | CHECKPOINT-MIB-2 |
| 1.3.6.1.2.1.2.2.1.4 | ifMtu | CHECKPOINT-MIB-2 |