Kolmisoft Blog

How to send emergency calls from a blocked VoIP…

A prepaid balance, a credit limit, and a user marked Blocked exist to stop calls. 999 and 112 are calls, so the same checks...

Mindaugas Kezys
Nov 2, 2026 6 min read

Forwarded calls fail when the carrier rejects the CLI

A forward to a mobile stops, and the handset reports that call forwarding failed. On the outbound INVITE the From number was the original...

Mindaugas Kezys
Nov 2, 2026 5 min read

Check your SIP TLS certificate before 2027

Let’s Encrypt removed TLS Client Authentication from its default certificates on 2026-02-11. On 2026-07-08 it retired the temporary tlsclient profile and stopped issuing that...

Mindaugas Kezys
Nov 2, 2026 6 min read

Softswitch migration: match invoices before cutover

Billing breaks a softswitch migration: balances, rate plans, the CDR file, and the first invoice. Bill one month of the old call records on...

Mindaugas Kezys
Oct 26, 2026 6 min read

Answer an ITG traceback from your own CDRs

An ITG traceback response starts in your CDRs. Search Calls List by time, source and destination, name the Origination Point, and stop that trunk.

Mindaugas Kezys
Oct 26, 2026 6 min read

What your softswitch can stop in a SIP DDoS…

You run MOR or M4 yourself. By the end you can tell a full pipe from a SIP flood, set the switch controls that...

Mindaugas Kezys
Oct 26, 2026 9 min read

2026 October: Two critical PHP bugs

On 21 October 2026 the PHP project released fixes for two critical bugs, CVE-2026-109618 and CVE-2026-109619. PHP scored each one CVSS 9.2. On a...

Mindaugas Kezys
Oct 22, 2026 4 min read

High Asterisk CPU: find the cause before a restart

Asterisk at 150% or 250% feels like the server is finished. On a host with several cores, that number can be one or two...

Mindaugas Kezys
Oct 21, 2026 14 min read

Introducing Italian, Ukrainian, and Spanish on Kolmisoft.com

Read Kolmisoft.com in English, Italian, Ukrainian, or Spanish. Choose your language on the homepage, then explore softswitches, pricing, and contact pages the way you...

Mindaugas Kezys
Oct 16, 2026 2 min read

How MOR pricing is calculated: own server or hosted Operators ask for one Class 5 softswitch price. A reseller selling SIP trunks and a virtual PBX does not buy the same system as a carrier pushing wholesale minutes, so Kolmisoft does not publish... Read More

How big a system: concurrent calls, CPS and servers A request for “500 or 1,000 concurrent calls, one server or two, our hardware or hosted” still leaves the second number blank. Concurrent calls (CC) are the calls up at one moment: ringing, setting... Read More

2026 October Development Update MOR sends an onboarding email when a user is created, packs the recordings from a search into one download, and accepts SIP TLS from phones that register through the proxy. Hangup-cause audio can be... Read More

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