Why can't I find Tor's logs or how do I check Tor works normally?

Question

I've just upgraded Ubuntu and Tor has also been upgraded, as I use the package officially provided by the OS maintainers.

I did certain changes to the torrc file, namely I decided to run a bridge exit relay. Then I restarted Tor and wanted to check if it was working normally. I used to do this by either checking the /var/log/tor/log file or by checking my IP at https://torstatus.blutmagie.de/. But now I learned that Tor seems to have dropped logging several months ago, since I have no log files older than October, 25th, 2017, when I, probably, upgraded to Ubuntu 17.10.

I searched for occurrences of the "log" word in the default torrc file, and found mentions that now Tor outputs logs to STDERR and STDOUT and one can uncomment necessary lines in the block:

## Logs go to stdout at level "notice" unless redirected by something
## else, like one of the below lines. You can have as many Log lines as
## you want.
##
## We advise using "notice" in most cases, since anything more verbose
## may provide sensitive information to an attacker who obtains the logs.
##
## Send all messages of level 'notice' or higher to /var/log/tor/notices.log
#Log notice file /var/log/tor/notices.log
## Send every possible message to /var/log/tor/debug.log
#Log debug file /var/log/tor/debug.log

I included those lines in an included file, so in the /etc/tor/torrc I have:

%include /etc/torrc.custom

And in the /etc/torrc.custom I have:

## Send all messages of level 'notice' or higher to /var/log/tor/notices.log
#Log notice file /var/log/tor/notices.log
## Send every possible message to /var/log/tor/debug.log
Log debug file /var/log/tor/debug.log

And I still don't see any log files.

Could anyone help me with this? How can I find the log files or how can I check my bridge relay works normally?

Thank you.

Answer 1

Debug level logging is disabled as it would contain information that could be dangerous to keep around. If your bridge had serious problems that prevented it from working, these would be available in the standard logging setup.

The easiest way to tell that your bridge is working (if it is not a private bridge) is to check Relay Search. You will not be able to search for your bridge by IP address, as the IP address of your bridge is secret! The idea for bridges is that the IP addresses are not known to everyone, so they can't all be blocked at once like relays. Instead, you can search for your bridge using the hashed fingerprint. This prevents leaking the fingerprint of the bridge when searching. You can find this in the hashed-fingerprint file in the Tor data directory. On Debian (and probably Ubuntu) systems, this is in /var/lib/tor but may be in another location on your system. The location is specified as DataDirectory in your torrc.

For more advice on monitoring and keeping your relay up to date, see the new Tor Relay Guide.