Interesting, attempted to replicate here with python’s simple http server but not seeing this happen.
Do you have any http proxying configured in steam and/or at the system level?
No; not deliberately at any rate. None of the proxy-related modules are loaded in Apache and I have no idea how to configure that for Steam itself.
Also, I was mistaken about it being fully reproducible during installation - it is perhaps more likely to happen then, but I had to retry downloading a game a few times before anything showed up in the log.
This may be relevant: entries from Steam's content_log.txt corresponding to Apache access_log.
content_log.txt:
[2014-04-29 18:38:33] Starting update AppID 41100: download 0/27209216, store 0/0, reuse 0/0, stage 0/124667526
[2014-04-29 18:38:33] HTTP (CDN,11) - content7.steampowered.com (content7.steampowered.com): AuthenticateDepotID (41102) - Success!
[2014-04-29 18:38:33] HTTP (CS,97) - valve14.cs.steampowered.com (valve14.cs.steampowered.com): AuthenticateDepotID (41102) - Success!
[2014-04-29 18:38:33] HTTP (CS,124) - valve24.cs.steampowered.com (valve24.cs.steampowered.com): AuthenticateDepotID (41102) - Success!
[2014-04-29 18:38:33] Scheduler update appID 41100: Priority Last, legacy=no, restore=""
[2014-04-29 18:38:33] HTTP (CDN,1) - content1.steampowered.com (content1.steampowered.com): AuthenticateDepotID (41102) - Success!
[2014-04-29 18:38:38] HTTP (CS,124) - valve24.cs.steampowered.com (valve24.cs.steampowered.com): Received 404 (Not Found) HTTP response
[2014-04-29 18:38:39] HTTP (CDN,1) - content1.steampowered.com (content1.steampowered.com): Received 404 (Not Found) HTTP response
[2014-04-29 18:38:43] HTTP (CS,124) - valve24.cs.steampowered.com (valve24.cs.steampowered.com): Received 404 (Not Found) HTTP response
[2014-04-29 18:38:43] HTTP (CS,124) - valve24.cs.steampowered.com (valve24.cs.steampowered.com): Received 404 (Not Found) HTTP response
access_log:
127.0.0.1 - - [29/Apr/2014:18:38:38 +0300] "GET /depot/41102/chunk/e548bf91c2658f3d49553b01a292eb83bc0d68a3 HTTP/1.1" 404 990
127.0.0.1 - - [29/Apr/2014:18:38:38 +0300] "GET /depot/41102/chunk/e3c76ee08f0764d8ca6aa15321ca0cab68786256?p=45&e=1399390713&h=695234e4061366a33e0269be81b0f5c3 HTTP/1.1" 404 988
127.0.0.1 - - [29/Apr/2014:18:38:43 +0300] "GET /depot/41102/chunk/3644e1e0864aaa49f52aa181eae960c9b21ee584 HTTP/1.1" 404 990
127.0.0.1 - - [29/Apr/2014:18:38:43 +0300] "GET /depot/41102/chunk/252df3a3e81bbc20f701f4a0cb3bd57554f5ccab HTTP/1.1" 404 990
localhost:80 accesses, no proxies
dec 28 06:29:21 nginx[250]: 2014/12/28 06:29:21 [error] 306#0: *1 open() "/usr/share/nginx/html/steamcommunity/public/images/avatars/e3/e3806ecace48478e1a42b2e6f591b2cba52f43b8.jpg" failed (2: No such file or directory), client: 127.0.0.1, server: localhost, request: "GET /steamcommunity/public/images/avatars/e3/e3806ecace48478e1a42b2e6f591b2cba52f43b8.jpg HTTP/1.1", host: "media.steampowered.com"
jan 02 19:40:36 nginx[232]: 2015/01/02 19:40:36 [error] 301#0: *3 open() "/usr/share/nginx/html/depot/731/chunk/705acdd73d176a41bc686d27c1b8ebe7f6f82aee" failed (2: No such file or directory), client: 127.0.0.1, server: localhost, request: "GET /depot/731/chunk/705acdd73d176a41bc686d27c1b8ebe7f6f82aee?token=exp=1420824193~acl=/depot/731/*~hmac=0ab1a6392ed21111b877d1488105ce9d91a98ef8 HTTP/1.1", host: "content8.steampowered.com"
jan 14 03:29:35 nginx[264]: 2015/01/14 03:29:35 [error] 298#0: *161 open() "/usr/share/nginx/html/appinfo/17740/sha/86b41490b1c6d35fa192ff7cc6aba5e32055269e.txt.gz" failed (2: No such file or directory), client: 127.0.0.1, server: localhost, request: "GET /appinfo/17740/sha/86b41490b1c6d35fa192ff7cc6aba5e32055269e.txt.gz HTTP/1.1", host: "clientconfig.akamai.steamstatic.com"
jan 24 04:17:54 nginx[21720]: 2015/01/24 04:17:54 [error] 21722#0: *1597 open() "/usr/share/nginx/html/appinfo/204300/sha/6c31b83a0d0ee95e265faf7a036da0fd1ade36e2.txt.gz" failed (2: No such file or directory), client: 127.0.0.1, server: localhost, request: "GET /appinfo/204300/sha/6c31b83a0d0ee95e265faf7a036da0fd1ade36e2.txt.gz HTTP/1.1", host: "clientconfig.akamai.steamstatic.com"
jan 24 04:18:00 nginx[21720]: 2015/01/24 04:18:00 [error] 21722#0: *1601 open() "/usr/share/nginx/html/steamcommunity/public/images/avatars/52/528bc081166bd69946517cf95a7c6aad4380382c.jpg" failed (2: No such file or directory), client: 127.0.0.1, server: localhost, request: "GET /steamcommunity/public/images/avatars/52/528bc081166bd69946517cf95a7c6aad4380382c.jpg HTTP/1.1", host: "media.steampowered.com"
jan 24 04:18:00 nginx[21720]: 2015/01/24 04:18:00 [error] 21722#0: *1601 open() "/usr/share/nginx/html/steamcommunity/public/images/avatars/1f/1f9690c4ec2bca6ce19c7bfd6bb0c95e4805e7ea.jpg" failed (2: No such file or directory), client: 127.0.0.1, server: localhost, request: "GET /steamcommunity/public/images/avatars/1f/1f9690c4ec2bca6ce19c7bfd6bb0c95e4805e7ea.jpg HTTP/1.1", host: "media.steampowered.com"
jan 29 04:59:12 nginx[21720]: 2015/01/29 04:59:12 [error] 21722#0: *3327 "/usr/share/nginx/html/initsession/index.html" is not found (2: No such file or directory), client: 127.0.0.1, server: localhost, request: "POST /initsession/ HTTP/1.1", host: "valve10.cs.steampowered.com"
jan 29 07:01:15 nginx[21720]: 2015/01/29 07:01:15 [error] 21722#0: *3328 open() "/usr/share/nginx/html/depot/218093/chunk/7576246eae22c7a511b43658ec40ddf8eb8e8df5" failed (2: No such file or directory), client: 127.0.0.1, server: localhost, request: "GET /depot/218093/chunk/7576246eae22c7a511b43658ec40ddf8eb8e8df5 HTTP/1.1", host: "valve191.cs.steampowered.com"
jan 31 05:13:39 nginx[21720]: 2015/01/31 05:13:39 [error] 21722#0: *3452 open() "/usr/share/nginx/html/steamcommunity/public/images/avatars/37/377eae8b8cf07397a66940420192907641283d3d.jpg" failed (2: No such file or directory), client: 127.0.0.1, server: localhost, request: "GET /steamcommunity/public/images/avatars/37/377eae8b8cf07397a66940420192907641283d3d.jpg HTTP/1.1", host: "cdn.akamai.steamstatic.com"
feb 02 14:21:41 nginx[247]: 2015/02/02 14:21:41 [error] 301#0: *1 open() "/usr/share/nginx/html/client/tenfoot_images_all.zip.vz.956cec432c42f276af27f410d254fa27d51cdb30_11174100" failed (2: No such file or directory), client: 127.0.0.1, server: localhost, request: "GET /client/tenfoot_images_all.zip.vz.956cec432c42f276af27f410d254fa27d51cdb30_11174100 HTTP/1.1", host: "media3.steampowered.com"
feb 03 07:11:11 nginx[272]: 2015/02/03 07:11:11 [error] 318#0: *1 open() "/usr/share/nginx/html/appinfo/3990/sha/eb9278f64361b2d31c12f7132f460593ace29142.txt.gz" failed (2: No such file or directory), client: 127.0.0.1, server: localhost, request: "GET /appinfo/3990/sha/eb9278f64361b2d31c12f7132f460593ace29142.txt.gz HTTP/1.1", host: "clientconfig.akamai.steamstatic.com"
feb 03 07:11:15 nginx[272]: 2015/02/03 07:11:15 [error] 318#0: *1 open() "/usr/share/nginx/html/appinfo/65740/sha/21b62eec8f7ed6e275dda5e4774a3cff78843356.txt.gz" failed (2: No such file or directory), client: 127.0.0.1, server: localhost, request: "GET /appinfo/65740/sha/21b62eec8f7ed6e275dda5e4774a3cff78843356.txt.gz HTTP/1.1", host: "clientconfig.akamai.steamstatic.com"
feb 03 07:11:15 nginx[272]: 2015/02/03 07:11:15 [error] 318#0: *1 open() "/usr/share/nginx/html/appinfo/65780/sha/3190f8fd477ffaa2f501c0a42596073cda65453b.txt.gz" failed (2: No such file or directory), client: 127.0.0.1, server: localhost, request: "GET /appinfo/65780/sha/3190f8fd477ffaa2f501c0a42596073cda65453b.txt.gz HTTP/1.1", host: "clientconfig.akamai.steamstatic.com"
feb 06 10:27:53 nginx[307]: 2015/02/06 10:27:53 [error] 328#0: *1 open() "/usr/share/nginx/html/depot/731/chunk/646a115ad05901ceff04425c2590e61914600323" failed (2: No such file or directory), client: 127.0.0.1, server: localhost, request: "GET /depot/731/chunk/646a115ad05901ceff04425c2590e61914600323 HTTP/1.1", host: "valve164.cs.steampowered.com"
mar 09 13:31:44 nginx[274]: 2015/03/09 13:31:44 [error] 305#0: *12032 open() "/usr/share/nginx/html/depot/4001/chunk/874ddefc29e8194d666c4f84ad7a8c028b797e2d" failed (2: No such file or directory), client: 127.0.0.1, server: localhost, request: "GET /depot/4001/chunk/874ddefc29e8194d666c4f84ad7a8c028b797e2d HTTP/1.1", host: "valve188.cs.steampowered.com"
looking in steams content_log for that last request, it seems to successfully have made 4 requests before failing to valve188.cs.steampowered.com, date and time is in UTC+01:00 and accurate to the second
[2015-03-09 13:31:39] Scheduler update appID 4000: Priority Last, legacy=no, restore=""
[2015-03-09 13:31:39] AppID 4000 state changed : Update Required,Fully Installed,Update Running,
[2015-03-09 13:31:39] AppID 4000 update changed : Running,
[2015-03-09 13:31:39] AppID 4000 update changed : Running,Reconfiguring,
[2015-03-09 13:31:39] Got 20 download sources via "/serverlist/66/20/" from 162.254.198.12:80
[2015-03-09 13:31:39] Created download interface of type 'CS' (1) to host valve30.cs.steampowered.com (valve30.cs.steampowered.com)
[2015-03-09 13:31:39] Created download interface of type 'CS' (1) to host valve29.cs.steampowered.com (valve29.cs.steampowered.com)
[2015-03-09 13:31:39] Created download interface of type 'CS' (1) to host valve270.cs.steampowered.com (valve270.cs.steampowered.com)
[2015-03-09 13:31:40] HTTP (CS,90) - valve270.cs.steampowered.com (valve270.cs.steampowered.com): OpenConnection - ERROR: HTTP response 503 (Service Unavailable)
[2015-03-09 13:31:40] HTTP (CS,90) - valve270.cs.steampowered.com (valve270.cs.steampowered.com): Closing connection
[2015-03-09 13:31:40] Created download interface of type 'CS' (1) to host valve188.cs.steampowered.com (valve188.cs.steampowered.com)
[2015-03-09 13:31:40] HTTP (CS,106) - valve29.cs.steampowered.com (valve29.cs.steampowered.com): OpenConnection - Success!
[2015-03-09 13:31:40] HTTP (CS,39) - valve188.cs.steampowered.com (valve188.cs.steampowered.com): OpenConnection - Success!
[2015-03-09 13:31:40] HTTP (CS,39) - valve188.cs.steampowered.com (valve188.cs.steampowered.com): AuthenticateDepotID (4003) - Success!
[2015-03-09 13:31:40] HTTP (CS,106) - valve29.cs.steampowered.com (valve29.cs.steampowered.com): AuthenticateDepotID (4001) - Success!
[2015-03-09 13:31:40] HTTP (CS,39) - valve188.cs.steampowered.com (valve188.cs.steampowered.com): Depot 4003 request for manifest 2860038409505929544 - received 200 (OK) HTTP response
[2015-03-09 13:31:41] HTTP (CS,107) - valve30.cs.steampowered.com (valve30.cs.steampowered.com): OpenConnection - Success!
[2015-03-09 13:31:41] HTTP (CS,106) - valve29.cs.steampowered.com (valve29.cs.steampowered.com): Depot 4001 request for manifest 1278898471435425768 - received 200 (OK) HTTP response
[2015-03-09 13:31:41] AppID 4000 update changed : Running,
[2015-03-09 13:31:41] AppID 4000 update changed : Running,Validating,
[2015-03-09 13:31:41] Validating files (new target,full) ...
[2015-03-09 13:31:41] File validation finished: 35 files (7552431 bytes) total, 35 files (7552431 bytes) mismatched (37 msec).
[2015-03-09 13:31:41] AppID 4000 update changed : Running,
[2015-03-09 13:31:41] AppID 4000 update changed : Running,Preallocating,
[2015-03-09 13:31:42] AppID 4000 update changed : Running,
[2015-03-09 13:31:42] AppID 4000 update started : download 0/53394640, store 0/0, reuse 0/643089687, stage 0/775464320
[2015-03-09 13:31:42] AppID 4000 state changed : Update Required,Fully Installed,Update Running,Update Started,
[2015-03-09 13:31:42] AppID 4000 update changed : Running,Downloading,
[2015-03-09 13:31:42] AppID 4000 update changed : Running,Downloading,Staging,
[2015-03-09 13:31:42] HTTP (CS,39) - valve188.cs.steampowered.com (valve188.cs.steampowered.com): AuthenticateDepotID (4001) - Success!
[2015-03-09 13:31:42] HTTP (CS,107) - valve30.cs.steampowered.com (valve30.cs.steampowered.com): AuthenticateDepotID (4001) - Success!
[2015-03-09 13:31:44] HTTP (CS,39) - valve188.cs.steampowered.com (valve188.cs.steampowered.com): Received 404 (Not Found) HTTP response
[2015-03-09 13:31:54] Increasing target number of download connections to 4 (rate was 0,000, now 12,847)
[2015-03-09 13:31:54] Current download rate: 12,847 Mbps
[2015-03-09 13:31:54] Created download interface of type 'CS' (1) to host valve10.cs.steampowered.com (valve10.cs.steampowered.com)
[2015-03-09 13:31:54] HTTP (CS,89) - valve10.cs.steampowered.com (valve10.cs.steampowered.com): OpenConnection - Success!
[2015-03-09 13:31:54] HTTP (CS,89) - valve10.cs.steampowered.com (valve10.cs.steampowered.com): AuthenticateDepotID (4001) - Success!
[2015-03-09 13:32:55] Current download rate: 0,212 Mbps
[2015-03-09 13:33:01] HTTP (CS,39) - valve188.cs.steampowered.com (valve188.cs.steampowered.com): Closing connection
[2015-03-09 13:33:01] HTTP (CS,106) - valve29.cs.steampowered.com (valve29.cs.steampowered.com): Closing connection
[2015-03-09 13:33:01] HTTP (CS,89) - valve10.cs.steampowered.com (valve10.cs.steampowered.com): Closing connection
[2015-03-09 13:33:02] HTTP (CS,107) - valve30.cs.steampowered.com (valve30.cs.steampowered.com): AuthenticateDepotID (4003) - Success!
[2015-03-09 13:33:56] Current download rate: 0,341 Mbps
[2015-03-09 13:34:56] Current download rate: 0,201 Mbps
[2015-03-09 13:35:57] Current download rate: 0,926 Mbps
[2015-03-09 13:36:58] Current download rate: 0,102 Mbps
[2015-03-09 13:37:58] Current download rate: 0,286 Mbps
[2015-03-09 13:38:59] Current download rate: 0,200 Mbps
[2015-03-09 13:39:34] AppID 4000 update changed : Running,
[2015-03-09 13:39:34] AppID 4000 update changed : Running,Committing,
[2015-03-09 13:39:34] AppID 4000 state changed : Fully Installed,Update Running,
[2015-03-09 13:39:34] Finished update AppID 4000, mounted depots (BuildID 546343): 4001 (1278898471435425768),4003 (2860038409505929544),
[2015-03-09 13:39:34] AppID 4000 update changed : Running,
[2015-03-09 13:39:34] AppID 4000 update changed : None
[2015-03-09 13:39:34] AppID 4000 state changed : Fully Installed,
[2015-03-09 13:39:34] AppID 4000 scheduler finished : removed from schedule
[2015-03-09 13:40:00] Current download rate: 0,000 Mbps
[2015-03-09 13:40:33] HTTP (CS,107) - valve30.cs.steampowered.com (valve30.cs.steampowered.com): Closing connection
Nothing extracted yet.
I run an Apache HTTP server on my desktop machine for personal use, and Steam client shows up in its access logs looking for remote files. The Apache daemon is listening to ports 80 and 81. Here are some lines from the access logs:
It does not appear to have any effect on performance as the files are ultimately received from their correct remote locations. It also doesn't happen all the time and is in fact somewhat difficult to reproduce (installing or updating a game seems to always generate a few /depot/.../chunk/... requests, but the community image ones are harder to pin down). Still, it pollutes server logs and does not appear to serve any purpose.