I recently lost a surprising amount of time trying to configure my router for my new DSL contract. Here's what I eventually learned, in case it might help someone else:

Drillisch GmBH and their brands

Drillisch GmBH is a German ISP and mobile network provider operating a large number of brands, including (but not limited to)

• DeutschlandSIM
• handyvertrag.de
• maXXim
• PremiumSIM
• sim.de
• simplytel
• smartmobil.de
• winSIM
• yourfone ... as well as a large number of discontinued brands.

I have no idea why they do this, given that these brands almost all have the exact same offers at the same price. Their offers are generally pretty good though, especially compared to the mainstream brands (but with their mobile contracts, you may have to pay attention to disable e.g. some "data auto-renewal" features, which could otherwise lead to some unexpected costs).

They also offer DSL. And of course, you can choose to use your own router rathen than a rented one - except, for some reason, they don't provide you with the necessary credentials for setup by default. You have to call customer service first. Or continue reading, if you prefer not having to speak to humans ;)

PPPoE credentials

You will first have to generate a password for PPPoE, which you can do in the service portal of your provider under "Kundendaten" > "Internetzugangsdaten". You will find a "Zugangskennung" da0000-000 (the digits vary, the da is always the same) and a password.

Annoyingly, this "Zugangskennung" is not the full username! The full username, instead, is Hinternet/da0000-000@de-access.de¹.

Setting	Value
Connection type	PPPoE
Username	Hinternet/da0000-000@de-access.de1
Password	(found in the service portal)
VLAN-ID	7
VLAN Priority	0

Make sure to enable IPv6, as well as DS-Lite for IPv4 access. You may also have to enable detecting the AFTR address via DHCPv6.

SIP credentials (Telephony)

Even once you contact customer service about your PPPoE credentials, they still don't send you the necessary information for SIP telephony. Luckily, I was able to find the necessary information provided here by user 'linko'.

You first need to choose a telephony password in the service portal under "Service" > "Telefonie-Passwort".

Setting	Value
Telephony Provider (if asked)	German-Local
SIP server / Registrar address	sip.de-access.de
Phone number	(your phone number, including leading zero)
SIP username	(your phone number without the leading zero, prefixed with 49)
IPv6	enabled

Suppose your phone number is 0221 4710471². Then you would use 02214710471 as the phone number and 492214710471³ as the SIP username.

You can also (at least on some routers) optionally specify the area code (in this case, 0221), so that you can omit it when making local phone calls.