How to get CNTLM gateway logs?

Question

I have CNTLM with gateway enabled running in a Linux machine. Many other machines on the same network are configured to use this as proxy.

I searched for cntlm.log in Ubuntu and couldn't find such a file.

How could, I see the logs of all the request coming through CNTLM (intercept the request)?

Answer 1

If you started cntlm as a system service on startup you can call sudo service cntlm status to see the current status and view the last ten connection messages, that should look something like this:

sschneid@sschneidschnee ~ $ sudo service cntlm status 
● cntlm.service - LSB: Authenticating HTTP accelerator for NTLM secured proxies
   Loaded: loaded (/etc/init.d/cntlm; bad; vendor preset: enabled)
   Active: active (running) since Mi 2018-04-04 08:29:25 CEST; 2h 7min ago
     Docs: man:systemd-sysv-generator(8)
  Process: 1483 ExecStart=/etc/init.d/cntlm start (code=exited, status=0/SUCCESS)
    Tasks: 11
   Memory: 3.1M
      CPU: 1.670s
   CGroup: /system.slice/cntlm.service
           └─1620 /usr/sbin/cntlm -U cntlm -P /var/run/cntlm/cntlm.pid

Apr 04 10:35:06 M0024 cntlm[1620]: 127.0.0.1 CONNECT media-cdn.ubuntu-de.org:443
Apr 04 10:35:06 M0024 cntlm[1620]: 127.0.0.1 CONNECT media-cdn.ubuntu-de.org:443
Apr 04 10:35:06 M0024 cntlm[1620]: 127.0.0.1 CONNECT media-cdn.ubuntu-de.org:443
Apr 04 10:36:18 M0024 cntlm[1620]: 127.0.0.1 CONNECT krebsonsecurity.com:443
Apr 04 10:36:19 M0024 cntlm[1620]: 127.0.0.1 CONNECT www.youtube.com:443
Apr 04 10:36:20 M0024 cntlm[1620]: 127.0.0.1 CONNECT www.google.com:443
Apr 04 10:36:21 M0024 cntlm[1620]: 127.0.0.1 CONNECT i.ytimg.com:443
Apr 04 10:36:21 M0024 cntlm[1620]: 127.0.0.1 POST http://ocsp.pki.goog/GTSGIAG3
Apr 04 10:36:33 M0024 cntlm[1620]: 127.0.0.1 CONNECT tiles.services.mozilla.com:443
Apr 04 10:36:34 M0024 cntlm[1620]: 127.0.0.1 CONNECT img-getpocket.cdn.mozilla.net:443

Generally, CNTLM logs to SYSLOG, so that would be another spot to search for your logged information.

Answer 2

In addition to @SSchneids answer you may use journalctl and filtering by unit via -u:

[14:15:16][root@host]:~# journalctl -u cntlm.service
-- Logs begin at Fri 2018-06-22 13:42:39 CEST, end at Fri 2018-06-29 13:20:30 CEST. --
Jun 28 14:07:08 host.example.com systemd[1]: Starting CNTLM HTTP Accelerator For NTLM Secured Proxies Authenticator...
Jun 28 14:07:08 host.example.com systemd[1]: Started CNTLM HTTP Accelerator For NTLM Secured Proxies Authenticator.
Jun 28 14:07:08 host.example.com cntlm[45762]: Daemon ready
Jun 28 14:07:08 host.example.com cntlm[45762]: Changing uid:gid to 1000:1000 - Success
Jun 28 14:08:32 host.example.com cntlm[45762]: Using proxy proxy.example.com:8080
Jun 28 14:09:37 host.example.com cntlm[45762]: 127.0.0.1 GET http://www.example.com/
Jun 28 14:09:37 host.example.com cntlm[45762]: 127.0.0.1 CONNECT www.example.com:80
Jun 28 14:10:10 host.example.com systemd[1]: Stopping CNTLM HTTP Accelerator For NTLM Secured Proxies Authenticator...
Jun 28 14:10:10 host.example.com systemd[1]: Stopped CNTLM HTTP Accelerator For NTLM Secured Proxies Authenticator.