ipcache Report

This is a report of the Squid DNS cache for domain name resolution.

Example Report

IP Cache Statistics:
IPcache Entries In Use:  13
IPcache Entries Cached:  13
IPcache Requests: 3502
IPcache Hits:            3451
IPcache Negative Hits:       0
IPcache Numeric Hits:        0
IPcache Misses:          51
IPcache Retrieved A:     51
IPcache Retrieved AAAA:  51
IPcache Retrieved CNAME: 2
IPcache CNAME-Only Response: 0
IPcache Invalid Request: 0

IP Cache Contents:

 Hostname                        Flg lstref    TTL  N(b)
 www.iana.org                           566   -506  2( 0)                             2620:0:2d0:200::8-OK 
 example.com                            585  20637  2( 0)                           2001:500:88:200::10-OK 
 ip6-allhosts                     H    2590     -1  1( 0)                                       ff02::3-OK 
 ip6-allrouters                   H    2590     -1  1( 0)                                       ff02::2-OK 
 ip6-allnodes                     H    2590     -1  1( 0)                                       ff02::1-OK 
 ip6-mcastprefix                  H    2590     -1  1( 0)                                        ff00::-OK 
 ip6-localnet                     H    2590     -1  1( 0)                                        fe00::-OK 
 ip6-loopback                     H    2590     -1  1( 0)                                           ::1-OK 
 ip6-localhost                    H    2590     -1  1( 0)                                           ::1-OK 
 localhost                        H    2590     -1  1( 0)                            

FAQ about this report

What's the difference between a hit, a negative hit and a miss?

  • A HIT means the domain was found in the cache.
  • A MISS means the domain was not found in the cache.
  • A numeric hit means the supposed domain name was an IP address literal, DNS was not needed to resolve anything.
  • A negative Hit means the domain was found in the cache, but the record indicated that it doesn't exist.

What do the IP cache contents mean anyway?

The hostname is the name that was requested to be resolved.

For example:

IP Cache Contents:

 Hostname                      Flags lstref    TTL  N [IP-Number]
 gorn.cc.fh-lippe.de               C       0  21581 1
 lagrange.uni-paderborn.de         C       6  21594 1
 www.altavista.digital.com         C      10  21299 4
 example.com                       H      15    -1 1 

For the Flags column:

  • C means positively cached.

  • N means negatively cached.

  • P means the request is pending being dispatched.

  • D means the request has been dispatched and we're waiting for an answer.

  • H means it is an entry loaded from the system hosts file.

  • L means it is a locked entry because it represents a parent or sibling.

The TTL column represents "Time To Live" (i.e., how long the cache entry is valid). This is given by the DNS system when each IP is retrieved. It may be negative if the entry has already expired, in which case the next request to need it will perform new DNS lookups to fetch new IPs.

The N column is the number of IP addresses which the cache has records for this domain. With (b) the number of bad IPs, ones which have found to be unusable or not able to connect.

The rest of the line lists all the IP addresses that have been associated with that hostname entry. In Squid-3.1 and later lines starting with empty spaces are a continuation of the previous entry when it has multiple IP addresses.

  • The IP address entries are marked individually as -OK. Unless they are known to result in failed connect, when they get marked as -BAD.

Features/CacheManager/IpCache (last edited 2012-02-01 01:16:11 by AmosJeffries)