OPNsense Forum

English Forums => General Discussion => Topic started by: chemlud on February 18, 2026, 06:18:08 PM

Title: Deutsche Telekom - Glasferausbau
Post by: chemlud on February 18, 2026, 06:18:08 PM
Hi!

Have here a salesman stalking me with Telekom digging our street and placing fiber. Connection to the building is free only for the inital digging, if I book a fibre later, I would have to pay for connecting house with the fibre in the street (estimated cost some 800.- € I guess).

Question to me (besides no real use case for GBit and 150 MBit same monthly rate as for DSL with 150 MBit) is, as we have in this one-family-house two separate telephone numbers (different owners, but only one cable comming in, built in the early 1970ies), one analog, one DSL (both run by Deutsche Telekom):

- Is it possible to keep the DSL line (150MBit) and order fiber only for the analog phone number? Or will Deutsche Telkom kill off the old cable DSL when a fibre is installed?

Moreover:

- Have no experience with Deutsche Telekom fiber, will it be ipv6?

- What kind of termination for the fiber is usual? Do I need a modem, if I don't want to rent any Deutsche Telekom hardware at funny monthly rates?

Any experience with Deutsche Telekom on that?
Title: Re: Deutsche Telekom - Glasferausbau
Post by: Patrick M. Hausen on February 18, 2026, 06:36:39 PM
Telekom regularly delivers a single public IPv4 address and a /56 for IPv6. Both dynamic for consumers, fixed when you have a business contract.

You need an ONT ("fibre modem") which they will happily sell you for a reasonable one time fee, no recurring extra cost. I recommend getting it from them. Saves debates if the connection isn't working from the start. Also their technician will connect and activate it, if you bought theirs.

You can of course buy a new contract and keep your DSL line active, but why would you? iIf you "upgrade" your DSL line to fibre at least in our case you do not even need to configure new credentials. When the ONT is activated, the DSL line will go down, you switch your WAN interface from DSL modem to ONT, instant connection. PPPoE etc. all stays the same.

I had to add VLAN 7 in OPNsense, because with DSL I have the modems do that, but that was all.
Title: Re: Deutsche Telekom - Glasferausbau
Post by: chemlud on February 18, 2026, 10:38:42 PM
I want to keep the old DSL as I never do such a switch without redundancy. I prefer to pay for two lines and have at least one online ;-)

Worst case: Pay for two line and have zero online.

Especially if you travel a lot and loose your tunnels due to switching from DSL to fiber...
Title: Re: Deutsche Telekom - Glasferausbau
Post by: Patrick M. Hausen on February 18, 2026, 11:06:45 PM
In that case - buy ONT from Telekom, get new PPPoE credentials, configure as usual.
Title: Re: Deutsche Telekom - Glasferausbau
Post by: Maurice on February 18, 2026, 11:15:03 PM
You can keep using the existing phone line / DSL, these won't get shut down anytime soon.

Deutsche Telekom sells two types of basic ONTs for about the same price: The "Glasfaser-Modem 2" with a 2.5 Gig Ethernet port and an SFP module named "Glasfasermodem Digitalisierungsbox" (actually a Zyxel PMG3000-D20B). Both are known to work just fine. There are some reports about compatibility issues with the SFP in certain NICs, but it works fine for me in a MikroTik device.

I'd highly recommend getting your home connected. Even if you don't currently need the speed, it's more reliable than DSL, upload speed is 50% of download, power consumption is lower. And if the fiber itself is from Deutsche Telekom, you can typically get contracts from Vodafone, o2, 1&1 etc., too. Just like with DSL.

Cheers
Maurice