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Network Calc MTU/MSS Calculator
x402
Network Calc MTU/MSS Calculator is a paid API for AI agents from network-calc.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).
Calculates TCP MSS from a given MTU for IPv4/IPv6, computes effective MTU through tunnels (PPPoE, GRE, VXLAN, WireGuard, etc.), and counts IPv4 fragments for a payload size.
Price / call$0.02
Success—
StatusUnknown
How this service works
TCP MSS from an MTU for IPv4 or IPv6, effective MTU through tunnels (PPPoE, GRE, VXLAN, WireGuard) and IPv4 fragment counts.
Output
Returns the computed TCP MSS in bytes, the effective MTU after tunnel overhead deductions, the recommended MSS clamp value, fragmentation details (fragment count, per-fragment payload bytes, total IP bytes) when a payload size is provided, a human-readable summary, tunnel-specific notes, and any warnings or reasons behind the computed values.
Example use cases
PPPoE MSS clamping for DSL router
“I have a DSL connection using PPPoE with a 1500-byte physical MTU — what TCP MSS value should I clamp to for IPv4 so connections don't stall?”
VXLAN overlay effective MTU check
“My VXLAN overlay network sits on top of a 9000-byte jumbo Ethernet link — what is the effective MTU and TCP MSS for IPv4 traffic inside the tunnel?”
IPv4 fragmentation count for large UDP payload
“If I send a 4096-byte UDP datagram (including the 8-byte header) over an IPv4 link with a 1500-byte MTU and no tunnel, how many fragments will it produce and how big are they?”
Technical details
Endpoint
GEThttps://network-calc.x402tookit.com/mtu-mss?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need precise TCP MSS values for a specific MTU and tunnel combination, particularly when configuring firewall MSS clamping rules, diagnosing TCP black-hole issues through tunnels, or calculating IPv4 fragment counts for large UDP payloads. It covers a wide range of tunnel types (PPPoE, GRE, VXLAN, WireGuard, MPLS, etc.) and handles both IPv4 and IPv6, making it more specialized and accurate than manual header-subtraction calculations.
Side effects
- Missing required 'mtu' parameter returns a validation error
- Invalid tunnel enum value returns a 400 bad request
- MTU value below minimum (e.g. below 68 for IPv4) may return an error or edge-case result
- Requesting IPv6 fragmentation counts may return a not-applicable note since IPv6 does not fragment in transit
- Malformed query parameters return schema validation errors
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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