DHCP range starts with 194.77.30. Could that lead to problems?

Just noticed that our Lancom router has a DHCP range of 194.77.30.50 - 150.

Could that lead to problems? Because sometimes some devices can’t be reached (with static IPS above that range like 194.77.30.170) and I have not yet figured it out why.

I can’t find a definitive answer on the net if it really MUST be 192.168..

You need (fanfare)

RFC 1918 - Address Allocation for Private Internets

Your private (IPv4) network MUST use one of the ranges allocated by this RFC:

 10.0.0.0        -   10.255.255.255  (10/8 prefix)
 172.16.0.0      -   172.31.255.255  (172.16/12 prefix)
 192.168.0.0     -   192.168.255.255 (192.168/16 prefix)

Anything else is Just Plain Wrong. And you can tell them the people who built the internet said so.

^{_{OK, so there's really no MUST anywhere in that RFC, but in practice the internet shuns heretics who just grab random swaths of IP space for their private networks, and everyone uses the RFC-1918 reserved ranges for their designated purpose of private networks. Do it right and fix your configuration to use standard, RFC-confomant addresses for your private network, and I bet your funky unreachable devices issue will go away...}}

Some things that are missing from the answers and comments posted so far:

1. Manuel is from Sylt Island, which is an island in northern Germany.

2. The address range 194.77.30.50 - 150 is part of a block allocated to Interoute Deutschland GmbH (which is an LIR) by RIPE NCC (RIR).

3. It's completely possible (and probable) that Interoute Deutschland GmbH assigned this address range to this particular non-profit and they in turn configured it for use internally, hence the current DHCP configuration on the Lancom router.

4. However each of us feels about not using RFC 1918 addresses internally, if points 1 through 3 above are true, then this is a perfectly acceptable setup.

You do not have to use RFC 1918 space if your site is using public IP space. Check with your provider and see if that range is correct for your site. If it is, I suspect someone has a subnet mask incorrectly set