[squid-users] Squid transparent not caching apt requests from deb.debian.org

[zrm]

On 4/3/20 16:34, Alex Rousskov wrote:
> On 4/3/20 4:26 PM, zrm wrote:
>> In the first case we get TCP_MISS every time because it isn't caching
>> the data, in the second case it's only the first time and after that we
>> get TCP_REFRESH_UNMODIFIED. But how and why is this happening?
> 
> Those questions can often be answered by looking at HTTP headers
> received and sent by Squid when talking to clients and origin servers.
> You can see those headers in basic packet captures or if you set
> debug_options to ALL,2.
> 
> Alex.
> 

apt to squid:
---------
GET /debian/pool/main/v/vim/vim_8.1.0875-5_amd64.deb HTTP/1.1
Host: deb.debian.org
User-Agent: Debian APT-HTTP/1.3 (1.8.2)


----------
squid to deb.debian.org:
---------
GET /debian/pool/main/v/vim/vim_8.1.0875-5_amd64.deb HTTP/1.1
User-Agent: Debian APT-HTTP/1.3 (1.8.2)
Host: deb.debian.org
Via: 1.1 tproxy (squid/4.6)
X-Forwarded-For: 192.168.111.55
Cache-Control: max-age=259200
Connection: keep-alive


----------
deb.debian.org to squid:
---------
HTTP/1.1 200 OK
Server: Apache
X-Content-Type-Options: nosniff
X-Frame-Options: sameorigin
Referrer-Policy: no-referrer
X-Xss-Protection: 1
Last-Modified: Sat, 15 Jun 2019 17:46:35 GMT
ETag: "1389dc-58b605823fa6e"
X-Clacks-Overhead: GNU Terry Pratchett
Cache-Control: public, max-age=2592000
Content-Type: application/x-debian-package
Via: 1.1 varnish
Content-Length: 1280476
Accept-Ranges: bytes
Date: Fri, 03 Apr 2020 05:28:46 GMT
Via: 1.1 varnish
Age: 4248100
Connection: keep-alive
X-Served-By: cache-ams21028-AMS, cache-wdc5559-WDC
X-Cache: HIT, HIT
X-Cache-Hits: 1, 2
X-Timer: S1585891726.434375,VS0,VE0

----------
squid to apt:
---------
HTTP/1.1 200 OK
Server: Apache
X-Content-Type-Options: nosniff
X-Frame-Options: sameorigin
Referrer-Policy: no-referrer
X-Xss-Protection: 1
Last-Modified: Sat, 15 Jun 2019 17:46:35 GMT
ETag: "1389dc-58b605823fa6e"
X-Clacks-Overhead: GNU Terry Pratchett
Cache-Control: public, max-age=2592000
Content-Type: application/x-debian-package
Content-Length: 1280476
Accept-Ranges: bytes
Date: Fri, 03 Apr 2020 05:28:46 GMT
Age: 4248100
X-Served-By: cache-ams21028-AMS, cache-wdc5559-WDC
X-Cache: HIT, HIT
X-Cache-Hits: 1, 2
X-Timer: S1585891726.434375,VS0,VE0
X-Cache: MISS from tproxy
X-Cache-Lookup: MISS from tproxy:3130
Via: 1.1 varnish, 1.1 varnish, 1.1 tproxy (squid/4.6)
Connection: keep-alive


----------



wget to squid:
---------
GET /debian/pool/main/v/vim/vim_8.1.0875-5_amd64.deb HTTP/1.1
User-Agent: Wget/1.20.1 (linux-gnu)
Accept: */*
Accept-Encoding: identity
Host: deb.debian.org
Connection: Keep-Alive


----------
squid to deb.debian.org:
----------
GET /debian/pool/main/v/vim/vim_8.1.0875-5_amd64.deb HTTP/1.1
User-Agent: Wget/1.20.1 (linux-gnu)
Accept: */*
Accept-Encoding: identity
Host: deb.debian.org
Via: 1.1 tproxy (squid/4.6)
X-Forwarded-For: 192.168.111.55
Cache-Control: max-age=259200
Connection: keep-alive


----------
deb.debian.org to squid:
---------
HTTP/1.1 200 OK
Server: Apache
X-Content-Type-Options: nosniff
X-Frame-Options: sameorigin
Referrer-Policy: no-referrer
X-Xss-Protection: 1
Last-Modified: Sat, 15 Jun 2019 17:46:35 GMT
ETag: "1389dc-58b605823fa6e"
X-Clacks-Overhead: GNU Terry Pratchett
Cache-Control: public, max-age=2592000
Content-Type: application/x-debian-package
Via: 1.1 varnish
Content-Length: 1280476
Accept-Ranges: bytes
Date: Fri, 03 Apr 2020 05:28:49 GMT
Via: 1.1 varnish
Age: 4248102
Connection: keep-alive
X-Served-By: cache-ams21028-AMS, cache-wdc5583-WDC
X-Cache: HIT, HIT
X-Cache-Hits: 1, 1
X-Timer: S1585891729.316362,VS0,VE0

----------
squid to wget:
---------
HTTP/1.1 200 OK
Server: Apache
X-Content-Type-Options: nosniff
X-Frame-Options: sameorigin
Referrer-Policy: no-referrer
X-Xss-Protection: 1
Last-Modified: Sat, 15 Jun 2019 17:46:35 GMT
ETag: "1389dc-58b605823fa6e"
X-Clacks-Overhead: GNU Terry Pratchett
Cache-Control: public, max-age=2592000
Content-Type: application/x-debian-package
Content-Length: 1280476
Accept-Ranges: bytes
Date: Fri, 03 Apr 2020 05:28:49 GMT
Age: 4248102
X-Served-By: cache-ams21028-AMS, cache-wdc5583-WDC
X-Cache: HIT, HIT
X-Cache-Hits: 1, 1
X-Timer: S1585891729.316362,VS0,VE0
X-Cache: MISS from tproxy
X-Cache-Lookup: MISS from tproxy:3130
Via: 1.1 varnish, 1.1 varnish, 1.1 tproxy (squid/4.6)
Connection: keep-alive


----------