Advanced Networking Guide

This guide covers the advanced networking features introduced in Simple PHP IPAM v2.4.0: VRF BGP attributes, VLAN ranges, IPv6 prefix delegation pools, and network aggregates.

Contents

• VRFs with BGP attributes
• VLAN ranges
• Aggregates
• IPv6 Prefix Delegation pools
• DNS zone export

VRFs with BGP attributes

Virtual Routing and Forwarding (VRF) instances allow overlapping address spaces across separate routing domains. Starting in v2.4.0, each VRF can optionally carry BGP metadata:

These fields are informational — IPAM does not generate BGP configuration. They serve as a reference when cross-referencing router configs.

When to use the "Enforce unique prefixes" flag

Leave this on (the default) for production VRFs where duplicate prefixes would be a misconfiguration. Turn it off for VRFs that intentionally host overlapping test or lab blocks.

Note: The UNIQUE constraint in the database operates on (cidr, vrf_id) — a CIDR may appear in multiple distinct VRFs. The "enforce unique" flag is stored for documentation purposes; the underlying DB constraint always prevents the same CIDR appearing twice within the same VRF.

VLAN ranges

VLAN ranges define named allocation blocks within the 1–4094 802.1Q VLAN ID space. They are purely organisational — they do not restrict which VLAN IDs can be created.

Use cases

• Segment VLANs by function: Management 1–99, Users 100–499, Server 500–999, Transit 900–999
• Track RIR-style allocation blocks across sites
• Document vendor-reserved ranges

Managing VLAN ranges

Navigate to Admin → VLANs and scroll to the VLAN Ranges section. Each range has:

• Name — short label, e.g. "Management"
• Min / Max — inclusive VLAN ID bounds (1–4094, min ≤ max)
• Site — optional scope (Global if unset)
• Description — free text

Ranges are display-only; no validation is enforced when creating individual VLANs outside a range.

Aggregates

Aggregates are top-level supernets — typically blocks assigned by a Regional Internet Registry (RIR) or defined by internal policy. They provide a bird's-eye view of address space ownership before it is subdivided into subnets.

Creating an aggregate

Navigate to Admin → Aggregates and fill in:

Both IPv4 and IPv6 aggregates are supported. The CIDR is normalised on save (host bits are zeroed).

Subnet coverage count

Each aggregate row shows a Subnets count — the number of subnets in the database whose prefix length is at least as specific as the aggregate's prefix (same IP version). This is a heuristic; it does not verify that subnets actually fall within the aggregate range.

IPv6 Prefix Delegation pools

Prefix Delegation (PD, RFC 3633) allows a delegating router to assign a prefix block to a requesting router (the subscriber). Simple PHP IPAM v2.4.0 adds a PD pool management interface under Admin → PD Pools.

Concepts

Workflow

1. Create a pool — select an existing IPv6 subnet (e.g. 2001:db8::/32) and specify the delegation prefix length (e.g. 48 → each subscriber gets a /48).
2. Delegate a prefix — click the pool's delegation count link to open the delegation view. Enter the specific CIDR to assign, optionally link a contact as the subscriber, and set an expiry date if applicable.
3. Revoke a delegation — use the Revoke button in the delegation list. This removes the record; it does not automatically update router configuration.

Expiry tracking

Delegations with a past expiry date are highlighted in red and marked Expired. There is no automatic revocation — expired delegations must be manually reviewed.

DNS zone export

Any subnet can be exported as a BIND-format zone file from the Addresses page using the DNS Export action.

Export types

URL format

/export_dns.php?subnet_id=<ID>&type=<forward|reverse|both>

Forward zone output

Each address with a non-empty Hostname field produces one A/AAAA record. The hostname is treated as an FQDN (a trailing . is added if absent).

$ORIGIN .
$TTL 3600

example.host.                            IN  A      10.0.1.5
another.host.                            IN  A      10.0.1.10

Reverse zone output (IPv4)

The PTR $ORIGIN is computed from the network address and prefix length. For a /24, the origin is X.Y.Z.in-addr.arpa.; for a /16, it is X.Y.in-addr.arpa.

$ORIGIN 1.0.10.in-addr.arpa.
$TTL 3600

5                              IN  PTR  example.host.
10                             IN  PTR  another.host.

Reverse zone output (IPv6)

IPv6 reverse zones use the nibble format with .ip6.arpa. suffix. The $ORIGIN covers the network prefix rounded up to the nearest nibble boundary.

Importing into BIND

The exported file is a partial zone file — it does not include SOA or NS records. Prepend those records before importing:

$ORIGIN example.com.
@ IN SOA ns1.example.com. admin.example.com. (
    2024010101 ; serial
    3600       ; refresh
    900        ; retry
    604800     ; expire
    300        ; minimum TTL
)
@ IN NS ns1.example.com.

; Include exported records below: