Hi there.
I have a CCR1009-8G-1S-1S+ running 6.38. Recently upgraded from 6.29.

Was there any changes to firmware updates which would have affected Skype connections and UDP hole punching?
Nothing in my FW config has changed and I can't connect Skype video calls to external networks.
Making Skype calls to a device internal to the network is always fine.
After reverting back to old firmware, calls to external networks work fine again.

Outbound UDP has always been blocked in my config except for the few basic ports: 80,443,123,53,1
I have Forward allow on some higher UDP ranges for some other web based VOIP solutions.

Any help appreciated!

Thanks

To be honest, I am glad I'm not the only one experiencing this.
RB951G-2HnD RouterOS 6.38.5 and most probably after touching the firewall/nat rules or the static DHCP, I cannot initiate or receive skype calls, while text messages are ok.
After reverting to 6.29.1 everything works...

Try disabling SIP at IP > Firewall | Service Ports tab.

Will test with SIP disabled.
SIP is there in 6.29.1 too, however in 6.38.5 there is a new service called udplite, which is not present in 6.29.1, wonder what is it, and whether could it be the reason for this?

Just did an upgrade to 6.38.5 and disabled dccp, sctp, sip, udplite in firewall service ports, and skype calls were NOT working.
Then I did a factory reset and restored the backup file created in 6.29.1, but did not downgrade, and behold: Skype calls are working with all service ports enabled in firewall. Once again, the same config was restored... Strange.
Most probably if I alter some configuration in firewall/nat, then Skype calls will not work again. I will not touch them now, I want to see when will it break on its own.

Blocking Skype is the way to go btw.

Blocking Skype is the way to go btw.

What do you mean?

6.39.2 - Skype is in "connecting", but doesn't connect. Everything else work. Skype connects fine if connected trough 3g router (i.e. not mikrotik).
Reset to default config doesn't help - same "Skype connecting"

6.39.2 - Skype is in "connecting", but doesn't connect. Everything else work. Skype connects fine if connected trough 3g router (i.e. not mikrotik).

Don't blame your mikrotik box, today (Jun 20) it's likely the Skype's problem: http://heartbeat.skype.com/2017/06/skyp ... blems.html.

Its not mikrotik problem, they have huge outage and services go randomly up/down