Opened 9 years ago

Closed 4 years ago

#2614 closed task (user disappeared)

Test Baidu reachability from exit nodes.

Reported by: cjb Owned by: cjb
Priority: Medium Milestone:
Component: Metrics/Analysis Version:
Severity: Normal Keywords:
Cc: Actual Points:
Parent ID: Points:
Reviewer: Sponsor:

Description

This bug describes a test to attempt to establish whether China is blocking our exit nodes simplex (incoming traffic to the node receives injected TCP reset packets) or duplex (all traffic to the node is blocked, in or out). Knowing this would be useful, because it will affect our bridge strategy -- if a bridge is blocked duplex and it knows it (by conducting a similar test), it could mark itself as blocked and be removed from the bridgedb.

The test consists of:

  • from each exit relay:
    • try to access a website in China
    • a duplex-blocked node will fail
    • a simplex-blocked node will succeed

The deliverable from the test should be a count of exit nodes that are blocked simplex vs. duplex.

Two possible methods are .exit notation or a SoaT test. SoaT is preferred.

Child Tickets

Change History (4)

comment:1 Changed 9 years ago by cjb

This is related to #1851 and #2576.

comment:2 Changed 9 years ago by arma

Component: MetricsTor Bridge

(Added to bridge component, even though it's about exit relays, because the motivation is to be able to make better decisions about bridges.)

comment:3 Changed 8 years ago by arma

Component: Tor BridgeAnalysis
Type: defecttask

comment:4 Changed 4 years ago by phw

Resolution: user disappeared
Severity: Normal
Status: newclosed

Recent research has shown that relays are blocked simplex. See, for example https://censorbib.nymity.ch/#Ensafi2015a

Nevertheless, if somebody wants to learn more about this, it should be easy to write an exitmap module that checks connectivity to baidu from all exit relays.

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