I saw some weird background activity on my network interface and undertook an investigation. netstat readily revealed that Firefox had a metric ton of TCP connections open:
yonami.local:58809 cdce.sef004.interna:www ESTABLISHED 7215/firefox-bin yonami.local:58828 cdce.sef004.interna:www ESTABLISHED 7215/firefox-bin yonami.local:33425 pv-in-f106.1e100.ne:www ESTABLISHED 7215/firefox-bin yonami.local:58829 cdce.sef004.interna:www ESTABLISHED 7215/firefox-bin yonami.local:46025 208.50.77.78:www ESTABLISHED 7215/firefox-bin yonami.local:46001 208.50.77.78:www ESTABLISHED 7215/firefox-bin yonami.local:41860 208.50.77.95:www ESTABLISHED 7215/firefox-bin yonami.local:45853 pv-in-f100.1e100.ne:www ESTABLISHED 7215/firefox-bin yonami.local:45339 px-in-f102.1e100.ne:www ESTABLISHED 7215/firefox-bin yonami.local:58807 cdce.sef004.interna:www ESTABLISHED 7215/firefox-bin yonami.local:58801 cdce.sef004.interna:www ESTABLISHED 7215/firefox-bin yonami.local:41861 208.50.77.95:www ESTABLISHED 7215/firefox-bin yonami.local:41864 208.50.77.95:www ESTABLISHED 7215/firefox-bin yonami.local:41862 208.50.77.95:www ESTABLISHED 7215/firefox-bin yonami.local:41863 208.50.77.95:www ESTABLISHED 7215/firefox-bin yonami.local:58808 cdce.sef004.interna:www ESTABLISHED 7215/firefox-bin yonami.local:56984 185-131.amazon.com:www ESTABLISHED 7215/firefox-bin yonami.local:52057 208.50.77.72:www ESTABLISHED 7215/firefox-bin yonami.local:41865 208.50.77.95:www ESTABLISHED 7215/firefox-bin
This was especially peculiar, because the only Firefox window I had open was to some totally static webpage. No Comet or other JavaScript funny-business going on there. No other Firefox tabs or windows open. So what the hell are all these other connections?
Googling reveals that 1e100.net are Google servers and that Firefox may have connections open to these to do Safebrowsing or other random bits. The others are mysterious: cdce.sef004.internap.net is probably some Internap CDN service, the 208.50.77.xx addresses all live behind verio-1.ar5.SEA1.gblx.net, and look like Akami servers. 185-131.amazon.com doesn’t even forward resolve (I didn’t save a copy of the netstat -na output).
Nothing looks especially nefarious, but why would I have so many lingering established connections? Surely if I close a tab, Firefox closes all keep-alive connections originating from that tab. Of course, when I killed Firefox, the network activity stopped.
Meanwhile, Chrome was running with tabs open to Gmail, another Gmail and Google Calendar. It’s open connections were explicable and substantially fewer:
yonami.local:45460 pv-in-f83.1e100.net:www ESTABLISHED 3002/google-chrome yonami.local:43754 pv-in-f139.1e100.:https ESTABLISHED 3002/google-chrome yonami.local:49226 pv-in-f83.1e100.n:https ESTABLISHED 3002/google-chrome yonami.local:35690 pv-in-f17.1e100.n:https ESTABLISHED 3002/google-chrome yonami.local:40323 pv-in-f83.1e100.net:www ESTABLISHED 3002/google-chrome
I won’t even start on Firefox’s memory utilization “patterns”. Either way, score another point for Chrome’s process-per-tab resource management model.