DNS server doesn't bind to all localhost interfaces.

Revertron / Alfis

Alternative Free Identity System

https://alfis.name

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DNS server doesn't bind to all localhost interfaces. #332

Closed zander closed 1 year ago

zander commented 1 year ago

Using the latest release (0.8.3) I run alfis under systemd.

Calling time drill flowee.ygg @localhost AAAA I notice I get a correct response very quickly, but once every 5 to 10 calls it just hangs for 15 seconds.

real    0m15,021s
user    0m0,003s
sys     0m0,003s

Even after nobody asked the server for half an hour, a call took 15 seconds. So there doesn't seem to be any shortage of workers (unless they don't die at all)

Revertron commented 1 year ago

Can you repeat that test now, when your blockchain is fully synced?

zander commented 1 year ago

My blockchain has been fully synched for all those tests.

I even mined my own domain, which is what the test tried to query. The result was correct 100% of the time, the hanging is just a problem.

Revertron commented 1 year ago

I can't reproduce it here. On Windows and Linux :(

zander commented 1 year ago

I restarted the server with debug level output, which revealed nothing useful.

My observations;

Debug messages like "connection 10 to IP has timed out" etc still continue to scroll by in the time the connection is waiting for answer.
forwarded requests also block, just like alfis lookups do.
its ALWAYS exactly 15 seconds extra.
using 'ping' to do lookups seems to work just fine.
Changing the number of threads to 100 had no effect.

Attached is are 2 strace logs, maybe that helps.

strace-normal.log strace-slow.log

Revertron commented 1 year ago

Both logs show Query time: 0 msec, maybe your terminal is taking 15 seconds to do something?

zander commented 1 year ago

Thats one explanation.

The socket connection and timeouts are a bit weird, though. It seems to connect 3 times to ::1 before trying to connect to 127.0.0.1

Looks like the problem is that your DNS server only binds to one localhost, not to the ipv6 localhost.

Revertron commented 1 year ago

your DNS server

Ha-ha :)

You have listen directive in /etc/alfis.conf that says where to bind.

zander commented 1 year ago

To add the info you explained in private chat;

Alfis is currently unable to bind to more than one interface. So a dual-stack system like my own where the 'localhost' has two interfaces will mean that the user needs to address the server by IP address instead of name (localhost).