Why a Router?

Router: With a router, you can create your own small computer network in your dorm room, where your devices usually go online via Wi-Fi through your router. Your router is connected to a device called a switch, which is typically located in the basement of your dorm. This switch is usually directly connected to us at Fichtenweg 5 in Tübingen via fiber optic cable. From there, the connection goes to the Data Center of the University of Tübingen, and from there to BelWü and beyond. The term Internet is based on the interconnectivity between networks.

To communicate between devices on the Internet, they need to find each other. For this, there are IP addresses, which we can compare to phone numbers for this explanation. We have a limited number of these addresses and can provide each of you with one. Since nowadays you have more than one device that wants to go online at the same time, it would cause problems without a router.

Access Point: An access point is not a router and does not create its own network. An access point is an entry point for a network. The access point needs an IP address to function. We give you exactly one IP address. If you connect an access point in your room, it gets an IP address from us. A smartphone connected to the access point does not go online at first, and you can’t access the access point because they don’t know each other’s addresses. The access point usually does not ask for a new IP address and forgets the assigned one after a while. A device in the Wi-Fi of the access point, such as a smartphone, continuously asks for an IP address and gets one from us after a maximum of two minutes if the access point has no more IP addresses. Then the smartphone can go online. Your laptop, however, will not go online through the access point. Therefore, you need a router.

Range Extender: Range extenders increase the range of a Wi-Fi network and do nothing else. So, you can’t do much with a range extender; at best, it might work like an access point.

Important Note: If you unplug your router and connect a laptop directly to the network socket, please wait 2 minutes before assuming there is an error or doing further diagnostics. The limitation to one IP address per room has a timer of 60 seconds. After 2 minutes, you will definitely have a new IP address from us if your devices are configured correctly.

Konrad-Adenauer-Strasse SoSe 2024

As announced on January 13, we are now using our standard configuration on Konrad-Adenauer-Strasse, after extending it for an additional month.

The change will prevent access points, repeaters, and incorrectly configured routers from using up too many IP addresses, which can deny other residents access to the internet.

Instructions on how to configure routers can always be found in our tutorials.

Maintenance work announcement Viktor-Renner-Straße

On Thursday, April 18, starting around 6:30 PM, we will finally be able to equip our dormitories in Viktor-Renner-Straße with more modern technology.
For the residents, this means they will be able to use gigabit internet in their rooms afterwards.
For us as Netz-AK the upgrade also brings us major advantages in the management of our network. The switches that were previously installed in Viktor-Renner-Straße are the very last to not support various standard features and needed to be configured very differently from the rest of our infrastructure, hindering any automation efforts.
We expect the installation to take about 3 hours, meaning you will probably have unrestricted internet access again from 9:30 PM.

Update 2024-04-23: After we were initially only able to replace the switches at Viktor-Renner-Straße 2 last Thursday, we have completed all maintenance work at 4 today. If you still have problems with your internet, please contact us individually using our contact form! This is the only way we can identify the individual problems and help you effectively, because the sources of error can be very different.

As everywhere else in our network, the maximum number of IP addresses assigned in Viktor-Renner-Straße is now basically limited to 1 per connection. However, you don’t have to buy a new router now if, for example, you have previously operated a WiFi repeater and therefore need several IP addresses. For all such connections that we could identify, we have temporarily relaxed this restriction. Let us know if we missed one.

We will no longer support FritzBox routers

Starting from April 1, 2024, we will no longer support FritzBox routers in our network.

For a short while now, we’ve had all the permissions needed to tackle the ongoing issue with FritzBox routers.

We’ve been advising against using FritzBox routers for a while due to their cost and features that are unnecessary for a student dormitory setting. We’ve also linked to this advice in our guide since 2022.

Besides the wasted money, we’ve received complaints from various dorm areas saying, “when I’m away for a while and come back, I have to unplug and replug my router to get online.”

We were able to reproduce this issue widely when we upgraded a slightly neglected dormitory to Gigabit at the beginning of the year. During the upgrade, the dormitory also received Alcatel switches, which we’ve been exclusively using since 2012. With these switches, those with compatible routers could now enjoy Gigabit, but for those using FritzBox, the situation got worse.

Currently, it seems that FritzBox routers are the only ones unable to obtain an IP from our DHCP server a second time, eventually going offline.

We are conducting a small test setup to try and replicate this phenomenon observed in the wild, but it’s taking time.

We should invest in the next generation of switches, but that takes too long considering the short time residents stay in the dormitory, making it unreasonable to ask anyone to daily reset their FritzBox.

Therefore, we’ve decided to phase out FritzBox routers from our network by April 1, 2024, the start of the summer semester.

Those with older devices can receive a special configuration for their connection from us. Old devices are defined as: FritzBox routers that were in use in either of the two dormitories before their upgrade (Konrad-A-Str. and Viktor-R-Str.), i.e., the winter semester of 2023-2024.

In all other dorm areas, FritzBox routers haven’t worked for almost a decade, so we see no legitimate reason for complaints.

Anyone buying a FritzBox, despite our advice since 2022, will have to live with potentially needing to reconnect it daily. We will not invest our volunteer time into a special connection configuration just because someone chose to spend more money on a product we advise against.

When and how we will deploy our next generation of switches, which manufacturer they will be from, and whether FritzBox routers will work with them is not yet decided, and we ask that you refrain from inquiries about this.

Those interested in network technology are, of course, welcome to discuss and research this issue with us, but “I paid a lot of money and want my device to work” is not an argument here!

In short: from the summer semester of 2024, we will no longer support FritzBox routers in our network.

Fiber optic advertisement for the dorm is retro.

Imagine you’re living in a student dorm that has had fiber optic since 1974. And then, in 2024, you suddenly get an advertisement for the “soon arrival of fiber optic” in your mailbox.


If everything goes well, by this year, every room will be equipped with a synchronous gigabit connection, meaning 1,000 megabits of both upload and download.

That’s at least our goal for the 20th anniversary of our Network Work-group

Four out of nearly 6000 connections blocked

In rare cases, we must temporarily block certain connections to protect our network. This is done because of what are called abuse reports, which indicate that abusive activities might be happening from a connection. We receive this report from the BelWü-CSIRT (Computer Security Incident Response Team), and our task is to stop the abuse with appropriate actions, which we do by turning off the connection of the room.

What is an abuse report?

In short, an abuse report is triggered when suspicious or unusual activities are observed coming from an internet connection. This could be, for example, sending spam emails or unauthorized attempts to access other computers. Often, you may not be aware of this behavior because it is usually caused by viruses or other malicious software that has secretly installed itself on one of the devices in the network.

No blame on you

We want to emphasize that such a blocking is in no way meant as a blame towards the affected users. In most cases, you are victims of malicious software acting without your knowledge. Our priority is to quickly identify and solve the problem to prevent further damage.

Why we block the connection

The fastest and most effective way to inform you about a possible security issue is by temporarily turning off the connection. This measure immediately attracts attention and prompts most users to contact us right away. This way, we can address the problem together as quickly as possible.

We are almost always available

Please note that we are also available on weekends and outside regular working hours. If your internet connection unexpectedly stops working, do not hesitate to contact us. We are ready to analyze the problem and offer you steps to solve it. Together, we can ensure that your connection is quickly safe and fully functional again.


The security and reliability of our network are very important to us. Through proactive measures like these, we want not only to ward off potential threats but also to raise awareness of the importance of network security. We thank you for your understanding and cooperation in keeping our shared digital environment safe.

If you have any questions or concerns, we are always here for you.

Maintenance Work Announcement week 3

In week 3, which is from January 15 to January 21, some maintenance work is scheduled.


The maintenance work starting on Friday will be long and unpleasant for the people in Hohenheim.
The fiber optic lines in Hohenheim to get extended to be used in a different location because of the renovations.
Without the fiber optic line, there will be no internet there.

The work will be carried out by a specialist company and is scheduled to start on Friday morning, which is January 19.
The work will take a long time, so we announce a complete internet outage in all student dormitories in Hohenheim from Friday morning to Saturday noon.

If it’s done faster, please avoid sending us messages all day. It won’t speed things up.
The company will complete their work as quickly as possible, and we will reconnect the fiber optics.

Tuebingen, Konrad-Adenauer-Strasse

On Thursday, January 18, starting around 5:30 PM, we will finally be able to equip our dormitories in Konrad-Adenauer-Strasse with modern technology.
For the residents, this means they will be able to use gigabit internet in their rooms afterwards.
Since we haven’t been able to implement the exclusive use of routers in Konrad-Adenauer-Strasse due to technical reasons, we will not enforce this immediately but only from the start of the summer semester (April 1, 2024).
We expect the installation to take about 3 hours, meaning you will probably have unrestricted internet access again from 9:00 PM.

Tuebingen, Schimpf-WG

There will be a maximum half-hour interruption in internet access at the Schimpf-WG. We had announced this work several times before but could never implement it due to problems accessing our hardware in the neighboring building. We cannot say exactly when this will be, but it will happen some evening between Monday and Thursday.

Quo vadis Gigabit?

In Geislingen, Sigmaringen, and Albstadt, we have installed Gigabit switches for quite some time. It was more of a coincidence that these places were equipped with Gigabit internet before Tübingen and Hohenheim.

We have just checked how many residents of the dormitories actually use the offered Gigabit internet.

The results are somewhat sobering: In Albstadt, 53% of the residents use the Gigabit internet, in Sigmaringen it’s 33%, and in Geislingen only 25%.

This raises the question of whether we have not informed well enough that Gigabit can be used with the right router, or whether the residents simply do not need such high internet speed.

Schimpf-Eck (Am Lustnauer Tor 1) September

The rooms at Schimpf Eck (at Lustnauer Tor 1) now all have network sockets!

The only thing left to connect you to the dorm’s fiber-optic network is to lay down the fiber-optic cables. We’ll figure out who’s doing it and how it’s done. In the meantime, there’s a wireless connection.

The construction work for a proper wireless operation should be finished in November. Until then, we have a temporary solution for you.

We are working on getting everything done in September, so you can have some internet by the time the semester starts.

Schimpf-Eck (Am Lustnauer Tor 1) July2023

Surprisingly, construction work for Schimpf started last week. Each room, as usual in our dormitories, will have its own network connection with a double network socket, and one connection will be active.

We don’t consider a comprehensive alternative like WLAN networking, which is often desired, to be practical here. Those who have dealt with connecting hundreds of devices to Eduroam will understand why we are avoiding it.

In each room, you can set up your own secure and easy-to-configure WLAN with a simple router for around €35, allowing you to connect everything from a printer to a PlayStation.

The connection of the WG units in Schimpf Eck depends on the work at Pfleghof, whose starting date is still unknown to us. As surprises are possible, we prefer not to estimate when it will be ready. Getting new DSL contracts doesn’t seem sensible to us. We hope that the WG units will find a fair solution to redistribute the internet access costs or find a way to get rid of these contracts once the dormitory is stably connected to our network.

The final connection via fiber optic to our network is planned but not yet confirmed.