[tor-relays] max TCP interruption before Tor circuit teardown?

Gordon Morehouse gordon at morehouse.me
Tue Oct 22 14:29:19 UTC 2013


-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

Gordon Morehouse:
> Gordon Morehouse:
>> I'm still waiting for another "storm" to test the 60 sec findtime
>> / 90 sec bantime guesses that I made (and just pushed to my
>> repo, BTW). Every time my relay crashes due to a storm, it takes
>> me that much longer to get Stable back, and the storms are
>> almost nonexistent until you have the Stable flag in my
>> observation.
> 
> Another circuit-creation storm (detectable as SYN flood on ORPort) 
> happened last night soon after reattaining my Stable flag
> (argh!!!) and the following limits on SYNs to the ORPort were not
> enough to save Tor from the oom-killer:
> 
> 1. Absolute limit avg 4 SYN per second with burst of 10 to ORPort,
> with an iptables REJECT (as opposed to DROP) for hosts that send
> SYNs when this limit has been reached.
> 
> 2. 90-second iptables DROP ban for hosts which exceed the above
> (and are thus logged) in any 60-second period.

I should have said "exceed the above 5 times" here.

> 
> Sigh.  More trial and error and another (figurative) century before
> I get my Stable flag back.

I'm going to try dropping the total SYN limit to 3/sec burst 8, extend
the watch time from 60 to 75 seconds, and decrease the max # of
exceeds from 5 to 4 and see how that does.

This is fairly Pi-specific.

Best,
- -Gordon M.
-----BEGIN PGP SIGNATURE-----

iQEcBAEBCgAGBQJSZou8AAoJED/jpRoe7/ujrBYH/jJesRC0xRzo8lAf/UVKCMPf
PCN+8HAbMxFcMJw6nd0/OQQKdA3wGU6YUv3BlfgeyP/a2Ro+g9f5MZo3rCR7bvNG
dLjMG3oB4rDAmwcFAxHbJlZumPjWNcFGVOFkkxIrY+sSIhQAssDMjqTlj+YTdDJF
sh69FRl01WwghP2ivzAUZaL/NKEKEAIhPmHLMyL62qbFNhdPAbL0JV+Z/EO0Y5Sg
QGXazl7MLyvqBFUrkftQukkbn2tPkWWXOQv8gbCXhlq9UHw1TTtDbcgJpOEcwltS
TJPWXKemE/AeV06+5Aa2GQ9PdMmfwoMd9v4GFu/sFIJScN1p4JaOcA4EF69sr1E=
=DGXF
-----END PGP SIGNATURE-----


More information about the tor-relays mailing list