VoIP Bandwidth Calculator: Per-Call and Total Bandwidth by Codec
Works out how much upload and download a number of concurrent calls needs for a given codec, packet interval, IP version, SRTP and VPN tunnel, with a byte-by-byte breakdown.
September 30, 2026
SIP SRV Checker: Free NAPTR, SRV and SIP TLS Test
Checks the DNS records SIP phones and trunks use to find your server: NAPTR transport preference, SRV records for UDP, TCP and TLS, and whether every target resolves correctly.
September 30, 2026
Port Phone Number to VoIP: 6 Steps and Common Rejections Explained
The six steps to move business phone numbers to a VoIP provider or cloud phone system, the documents carriers ask for, the reasons ports get rejected, and how to avoid missed calls on port day.
September 30, 2026
Migrate PBX to Cloud: 8-Step Plan From 3CX or Asterisk
An eight-step plan for moving from an on-premises 3CX, FreePBX or Asterisk system to a hosted phone system: what to inventory, how to test the network, how to pilot and port numbers, and what to keep when you switch the old PBX off.
September 30, 2026
SIP SRV Records: DNS Setup for 3 Transport Types
How SIP clients find a server through DNS (NAPTR, then SRV, then A/AAAA), the exact records to create for UDP, TCP and TLS, how priority and weight give failover, and how to test the result.
September 30, 2026
VoIP One-Way Audio Fix: 6 Checks for NAT and RTP
A step-by-step way to find why one side of a call cannot hear the other: read the SDP, check NAT settings in PJSIP and 3CX, confirm RTP reaches the PBX, and remove SIP ALG and short UDP timeouts.
September 30, 2026
VoIP Codec Bandwidth: G.711 vs G.729 vs Opus, Per-Call Figures
How much bandwidth each VoIP call really uses once packet headers are added, how SRTP and VPN tunnels change it, and how to size a connection for a given number of concurrent calls.
September 30, 2026
Disable SIP ALG on 9 Routers and Firewalls (One-Way Audio Fix)
What SIP ALG does, why it breaks modern VoIP, how to confirm it is rewriting your packets, and the exact commands to turn it off on MikroTik, Cisco IOS, Juniper SRX, FortiGate, SonicWall and Linux.
September 30, 2026
SIP Ports Firewall Rules: 4 Setups for CSF, firewalld and pfSense
Which ports a PBX really needs (SIP 5060/5061 and the RTP media range), how to open them in CSF, firewalld and pfSense, and how to restrict SIP to your trunk provider so scanners cannot brute-force extensions.
September 30, 2026