title: Hash Sum mismatch in apt-get update
body: <p>I am unable to install packages via apt-get. So, I tried apt-get update.</p>
  
  <pre><code># apt-get install vim
  Reading package lists... Done
  Building dependency tree       
  Reading state information... Done
  Package vim is not available, but is referred to by another package.
  This may mean that the package is missing, has been obsoleted, or
  is only available from another source
  
  E: Package 'vim' has no installation candidate
  
  # apt-get update
  Hit http://security.debian.org jessie/updates InRelease
  Ign http://httpredir.debian.org jessie InRelease 
  Hit http://security.debian.org jessie/updates/main Sources
  Hit http://httpredir.debian.org jessie-updates InRelease                                           
  Hit http://security.debian.org jessie/updates/main amd64 Packages       
  Hit http://security.debian.org jessie/updates/main Translation-en                                                  
  Get:1 http://httpredir.debian.org jessie-updates/main Translation-en/DiffIndex [736 B]
  Hit http://httpredir.debian.org jessie Release.gpg                                  
  Get:2 http://httpredir.debian.org jessie-updates/main Sources [1959 B]
  Err http://httpredir.debian.org jessie-updates/main Sources
  
  Get:3 http://httpredir.debian.org jessie-updates/main amd64 Packages [1963 B]
  Hit http://httpredir.debian.org jessie Release                                  
  Get:4 http://httpredir.debian.org jessie/main Translation-en [4582 kB]
  Get:5 http://httpredir.debian.org jessie/main Sources [1961 B]                                                                                                                          
  Err http://httpredir.debian.org jessie/main Sources                                                                                                                                     
  
  Get:6 http://httpredir.debian.org jessie/main amd64 Packages [1961 B]                                                                                                                   
  Err http://httpredir.debian.org jessie/main amd64 Packages                                                                                                                              
  
  Fetched 4591 kB in 14s (327 kB/s)                                                                                                                                                       
  W: Failed to fetch http://httpredir.debian.org/debian/dists/jessie-updates/main/source/Sources  Hash Sum mismatch
  
  W: Failed to fetch http://httpredir.debian.org/debian/dists/jessie-updates/main/binary-amd64/Packages  Hash Sum mismatch
  
  W: Failed to fetch http://httpredir.debian.org/debian/dists/jessie/main/source/Sources  Hash Sum mismatch
  
  W: Failed to fetch http://httpredir.debian.org/debian/dists/jessie/main/binary-amd64/Packages  Hash Sum mismatch
  
  E: Some index files failed to download. They have been ignored, or old ones used instead.
  </code></pre>
  
  <p>I have already tried the accepted answer here: <a href="https://stackoverflow.com/questions/15505775/debian-apt-packages-hash-sum-mismatch">debian apt packages hash sum mismatch</a></p>
  
  <p>I am naive but I believe it is httpredir.debian.org which is causing the problem. How can I update /etc/apt/sources.list? What alternative entries could I use?</p>