sudo apt-get not working

Question

I was trying to install re2c but terminal replies the following:

sudo apt-get install re2c
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following NEW packages will be installed:
  re2c
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 202 kB of archives.
After this operation, 385 kB of additional disk space will be used.
WARNING: The following packages cannot be authenticated!
  re2c
Install these packages without verification? [y/N] y
Err http://mirrordirector.raspbian.org/raspbian/ jessie/main re2c armhf 0.13.5-1
  Cannot initiate the connection to mirrordirector.raspbian.org:80 (2001:41c9:1:3ce::11). - connect (101: Network is unreachable) [IP: 2001:41c9:1:3ce::11 80]
E: Failed to fetch http://mirrordirector.raspbian.org/raspbian/pool/main/r/re2c/re2c_0.13.5-1_armhf.deb  Cannot initiate the connection to mirrordirector.raspbian.org:80 (2001:41c9:1:3ce::11). - connect (101: Network is unreachable) [IP: 2001:41c9:1:3ce::11 80]

E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?

Note: I have an internet connection and the browser is working easily. The only problem is with apt-get.

How can I resolve this?

Answer 1

If this isn't a transitory problem with the server in question, you may be in a situation where IPv6 isn't being routed for you. In that case, you could force IPv4 routing per ethanol100's instructions in this forum post: https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=125231

sudo apt-get update -o Acquire::ForceIPv4=true

If that works, you can make it permanent by adding this as /etc/apt/apt.conf.d/99force-ipv4:

Acquire::ForceIPv4 "true";

Answer 2

Sometimes (but not rarely), raspbian.org goes out of service. If you really can't wait, I suggest replacing it or adding another mirror.

You can completely replace your /etc/apt/sources.list file with the one below. I think the file is self-explanatory.

Make sure to run apt-get update after you update the source list.

# THIS IS THE DEFAULT ENTRY.
# To replace this, comment it out (add a # at the beginning). 
# Make sure to enable at least one other entry from the list below if you 
# decide to disable this one.
# Its okay to enable more than one mirror.
deb http://mirrordirector.raspbian.org/raspbian/ jessie main contrib non-free rpi

# Uncomment line below then 'apt-get update' to enable 'apt-get source'
#deb-src http://archive.raspbian.org/raspbian/ jessie main contrib non-free rpi

# MIRRORS BELOW.
# Uncomment a line (remove the #) to use it as a mirror.
# Take note I am using Raspbian Jessie. Change yours accordingly.
# -PANDALION98

#EUROPE
#deb http://mirror.ox.ac.uk/sites/archive.raspbian.org/archive/raspbian jessie main contrib non-free rpi
#deb http://raspbian.insideelectronics.co.uk/raspbian/ jessie main contrib non-free rpi
#deb http://raspbian.lag.re/raspbian jessie main contrib non-free rpi

#NORTH AMERICA
#deb http://mirror.nexcess.net/raspbian/raspbian/ jessie main contrib non-free rpi
#deb http://mirror.glennmcgurrin.com/raspbian/ jessie main contrib non-free rpi

#SOUTH AMERICA
#deb http://raspbian.ufms.br/raspbian/ jessie main contrib non-free rpi
#deb http://raspbian.c3sl.ufpr.br/raspbian/ jessie main contrib non-free rpi

#ASIA
#deb http://mirror.devunt.kr/raspbian/raspbian/ jessie main contrib non-free rpi
#deb http://mirror.rise.ph/raspbian/raspbian/ jessie main contrib non-free rpi

Answer 3

It's possible that it's trying to get to an out of date mirror?

Sudo apt-get update
Sudo apt-get upgrade

Then try again?

Answer 4

It may be that the pi is not connected to the internet. To confirm internet connectivity, do the following (from a command prompt):

ping google.com

The response should look something like the following if you have internet connectivity:

PING google.com (74.125.24.139) 56(84) bytes of data.
64 bytes from de (74.125.24.139): icmp_seq=1 ttl=50 time=23.9 ms
64 bytes from de (74.125.24.139): icmp_seq=2 ttl=50 time=17.1 ms

If you get no response from the ping, then you need to check your pi internet connection. You could start here: https://learn.adafruit.com/downloads/pdf/adafruits-raspberry-pi-lesson-3-network-setup.pdf

Answer 5

This is usually caused when raspbian.org is down.

Please use one of the alternate Raspbian Respository Mirrors that is close to you from here: http://www.raspbian.org/RaspbianMirrors. Check the Issues column to avoid using the mirror that has known issues.

Edit /etc/apt/sources.list file with elevated permissions. Example:

sudo vim /etc/apt/sources.list

Comment out original server URL and add new line with the mirror URL as follows (just an example):

# deb http://raspbian.raspberrypi.org/raspbian/ buster main contrib non-free rpi
deb http://mirror.aarnet.edu.au/pub/raspbian/raspbian/ buster main contrib non-free rpi

Save file.

Now run the following commands:

sudo apt update -y
sudo apt --fix-missing upgrade -y

Now try installing what you were trying to install.

sudo apt install re2c

Hope it works for you. It did for me.