Crazy congestion control behavior after r33195

[Jacek Wielemborek <d33tah () gmail com>]

List,

Today I discovered that -p- scanning both scanme.nmap.org and 8.8.8.8 on
the latest SVN trunk can lead to quickly finishing the scanning of
8.8.8.8 and sending one probe per second to scanme.nmap.org, which makes
the scan last for several hours. I didn't have the patience to wait for
the scan to complete, so here's a -d4 log - you can see that
active_probes keeps between 1 and 0 while cwnd is 300:

https://svn.nmap.org/!svn/bc/33201/nmap-exp/d33tah/uploads/r33198-incomplete-nmap_-p-_--unprivileged_-sT_-n_-Pn_-d4_scanme.nmap.org_8.8.8.8_stderr_to_stdout.log.lzma

(Short URL: https://tinyurl.com/mln7o6b )

Could somebody look at this? It could be nice to at least have a simpler
testcase to reproduce this. I tried things like --top-ports=40000 and
-p-40000, but only -p- (not even --top-ports=65535 and -p-65535!) lead
to the result - though this could be just bad luck.

Jacek

Attachment: signature.asc
Description: OpenPGP digital signature

_______________________________________________
Sent through the dev mailing list
http://nmap.org/mailman/listinfo/dev
Archived at http://seclists.org/nmap-dev/