Can I skip "Finding Local Interfaces"?

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asked 2019-01-23 22:29:33 +0000

feenyman99
108 ●23 ●26 ●35

Hi...

When I launch Wireshark, it takes ~30 seconds to initialize. Of this initialization time, the display indicates that about 25 seconds is spent "Finding Local Interfaces".

I use Wireshark virtually every day (I'm lucky that way!), and 99% of the time I am reading in an existing .pcap file. I almost never use Wireshark to capture the packets.

Is there a way for me to launch Wireshark in "No Capture" mode, so it does not bother looking for local interfaces?

(Always trying to be more efficient :-))

Thx...

feenyman99

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answered 2019-01-24 15:41:17 +0000

Jasper
24103 ●5 ●111 ●292 Düsseldorf, Germany

What I do currently (on WIndows) is to stop / disable the autostart capture service. For that you need to run a elevated (administrative) command prompt and enter

sc config npf start=demand             (if using WinPCAP)

sc config npcap start=demand           (if using npcap)

That prevents the capture driver to load on start. If I need to capture I open the elevated command prompt again and run

sc start npcap

which runs the npcap capture service until the next reboot, or until I stop it again using

sc stop npcap

If you use WinPCAP you need to replace "npcap" with "npf" in both commands.

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And for those with a more modern view, the PowerShell equivalents (also requiring an elevated prompt) are:

Set-Service npcap -StartupType Manual

and to start\stop the service

Start-Service npcap
Stop-Service npcap

again swapping "npcap" with "npf" for WinPcap.

grahamb ( 2019-01-24 15:50:47 +0000 )edit

Thanks @grahamb - I guess I'm on the "Old School" track :-)

Jasper ( 2019-01-24 15:55:53 +0000 )edit

There's hope for you yet @Jasper!

grahamb ( 2019-01-24 15:59:59 +0000 )edit

Note that, as per bug 15126, there are two parts to "Finding local interfaces" - there's finding the interfaces that libpcap/WinPcap/Npcap knows about and there's finding the extcap interfaces. The "It's really slow" part tends to be the extcap part; disabling the driver for WinPcap/Npcap on Windows only eliminates the "finding the interfaces that libpcap/WinPcap/Npcap knows about" part, so if disabling the driver doesn't speed things up significantly, the problem is with extcap.

Guy Harris ( 2019-01-24 18:14:59 +0000 )edit

In my case I wonder why, but extcap doesn't seem to be the problem - especially my tower PC starts Wireshark in fractions of a second compared to multiple seconds after I disable npcap

Jasper ( 2019-01-24 19:29:56 +0000 )edit

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answered 2019-01-23 22:46:07 +0000

grahamb

flag of United Kingdom of Great Britain and Northern Ireland

23835 ●4 ●976 ●227 https://www.wireshark.org

See bug 15126 that details this issue. An associated change was committed and is available in the nightly builds and will be in the forthcoming 3.0 release.

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