title: ERROR: Failed to create helper child read FD: UDP[::1]
body: <p>everyone, </p>
  
  <p>I'm new to squid, and I can't start my squid. Here is my problem, when typing: <code>sudo squid -N -d1</code> to start squid</p>
  
  <p>```</p>
  
  <pre><code>2018/04/17 20:32:25| Set Current Directory to /var/spool/squid 
  2018/04/17 20:32:25| Starting Squid Cache version 3.5.12 for x86_64-pc-linux-gnu... 
  2018/04/17 20:32:25| Service Name: squid 
  2018/04/17 20:32:25| Process ID 8714 
  2018/04/17 20:32:25| Process Roles: master worker 
  2018/04/17 20:32:25| With 65535 file descriptors available 
  2018/04/17 20:32:25| Initializing IP Cache... 
  2018/04/17 20:32:25| DNS Socket created at [::], FD 8 
  2018/04/17 20:32:25| DNS Socket created at 0.0.0.0, FD 9 
  2018/04/17 20:32:25| Adding nameserver 100.100.2.138 from /etc/resolv.conf 
  2018/04/17 20:32:25| Adding nameserver 100.100.2.136 from /etc/resolv.conf 
  2018/04/17 20:32:25| Logfile: opening log daemon:/var/log/squid/access.log 
  2018/04/17 20:32:25| Logfile Daemon: opening log /var/log/squid/access.log 
  2018/04/17 20:32:25| Unlinkd pipe opened on FD 15 
  2018/04/17 20:32:25| Local cache digest enabled; rebuild/rewrite every 3600/3600 sec 
  2018/04/17 20:32:25| Store logging disabled 
  2018/04/17 20:32:25| Swap maxSize 102400 + 262144 KB, estimated 28041 objects 
  2018/04/17 20:32:25| Target number of buckets: 1402 
  2018/04/17 20:32:25| Using 8192 Store buckets 
  2018/04/17 20:32:25| Max Mem  size: 262144 KB 
  2018/04/17 20:32:25| Max Swap size: 102400 KB 
  2018/04/17 20:32:25| Rebuilding storage in /var/spool/squid (clean log) 
  2018/04/17 20:32:25| Using Least Load store dir selection 
  2018/04/17 20:32:25| Set Current Directory to /var/spool/squid 
  2018/04/17 20:32:25| Finished loading MIME types and icons. 
  2018/04/17 20:32:25| HTCP Disabled. 
  2018/04/17 20:32:25| commBind: Cannot bind socket FD 19 to [::1]: (99) Cannot assign requested address 
  2018/04/17 20:32:25| commBind: Cannot bind socket FD 20 to [::1]: (99) Cannot assign requested address 
  2018/04/17 20:32:25| ERROR: Failed to create helper child read FD: UDP[::1] 
  2018/04/17 20:32:25| /var/run/squid/squid.pid: (2) No such file or directory 
  2018/04/17 20:32:25| WARNING: Could not write pid file 
  2018/04/17 20:32:25| Squid plugin modules loaded: 0 
  2018/04/17 20:32:25| Adaptation support is off. 
  2018/04/17 20:32:25| Accepting HTTP Socket connections at local=[::]:3128 remote=[::] FD 18 flags=9 
  2018/04/17 20:32:25| Done reading /var/spool/squid swaplog (0 entries) 
  2018/04/17 20:32:25| Store rebuilding is 0.00% complete 
  2018/04/17 20:32:25| Finished rebuilding storage from disk. 
  2018/04/17 20:32:25|         0 Entries scanned 
  2018/04/17 20:32:25|         0 Invalid entries. 
  2018/04/17 20:32:25|         0 With invalid flags. 
  2018/04/17 20:32:25|         0 Objects loaded. 
  2018/04/17 20:32:25|         0 Objects expired. 
  2018/04/17 20:32:25|         0 Objects cancelled. 
  2018/04/17 20:32:25|         0 Duplicate URLs purged. 
  2018/04/17 20:32:25|         0 Swapfile clashes avoided. 
  2018/04/17 20:32:25|   Took 0.03 seconds (  0.00 objects/sec). 
  2018/04/17 20:32:25| Beginning Validation Procedure 
  2018/04/17 20:32:25|   Completed Validation Procedure 
  2018/04/17 20:32:25|   Validated 0 Entries 
  2018/04/17 20:32:25|   store_swap_size = 0.00 KB 
  2018/04/17 20:32:26| storeLateRelease: released 0 objects 
  </code></pre>
  
  <p>```</p>
  
  <p>My system is ubuntu16.04. My Squid version is 3.5.12 and is installed using apt-get. </p>
  
  <p>Can anyone help me ?</p>