pascom Cloud Phone System Documentation and Release Notes

Port Overview | Firewall Configuration

Configure your firewall

Many companies have no restricted Internet access and can therefore use the pascom server immediately, without any adjustment to the firewall.

However, if you specify exactly which Internet services your company network may access, please activate the following ports in your firewall to allow smooth operation of the pascom phone system

Port Overview Cloud

Port Function Device Source Target
123/UDP/TCP Access to TimeServer (NTP) Your Network
5061/TCP SIP-Connection Your Network*
30.000-35.000/UDP RTP-Voice Your Network*
636/TCP LDAPS, Phonebook Your Network*
8884/TCP Phone Provisioning Your Network*
443/TCP Updates, Push, Fax, Voicemail, Recordings, Filetransfer, WebClient, Chat Your Network*
19302/UDP+TCP WebRTC / Google STUN
Your Network*,,,,
8885/TCP VPN Tunnel to PBX Your Network*


= pascom Server
= Desktop Client
= Mobile Client
= IP-Phone
= WebClient

| * = The can target different IP addresses

IP addresses of the outgoing (Cloud phone system)

The IP address used by the outgoing cloud phone system is dynamic and can change at any time. For this reason, it is not advisable to use this in a firewall rule.

Therefore, please use the pascom VPN Service to connect LDAP servers, for example.

IP addresses of the incoming (pascom Apps)

Instead of a fixed IPv4 or IPv6 IP address, use the DNS entry “ “. If you resolve it, you will get all IPv4 and IPv6 IP addresses that is using at the moment.

The DNS record “ “ can be used in two ways

Resolve DNS record manually

Resolve it manually with tools like “dig “ or “nslookup “ to get the IP addresses:

# ipv4 with dig:
dig +short A

# ipv6 with dig:
dig +short AAAA

# ipv4 with nslookup
nslookup -q=A

# ipv6 with nslookup
nslookup -q=AAAA

Set DNS entry directly in the firewall

Use the DNS record “ “ directly in your firewall as destination or source. This only works if your firewall can use or resolve DNS names instead of IP addresses and updates them regularly.

QoS settings marks voice and signal packets. Many routers / switches take this into account as standard or can be configured accordingly.

Package type TOS COS DSCP decimal
Voice ef / 184 5 46
Signaling cs3 / 96 3 24

All pascom clients also mark packages accordingly. Please note that group policies must be set for this under Windows. See Windows QoS Settings.