What does -tnn
mean in tcpdump -i eth0 -tnn dst port 80 -c 1000
. I didn't find -tnn
on the man page, and I didn't find it on the Internet. Can anyone explain it to me?
1 Answer
You can often combine options into one combined one to make typing easier.
In this case:
-nn
Don't convert protocol and port numbers etc. to names either.
-t
Don't print a timestamp on each dump line.
This also implies
-n
Don't convert host addresses to names. This can be used to avoid DNS lookups.
-
Thank you, but it's weird that
-nn
isn't shown in my linux tcpdump man page.– SeareneOct 2, 2015 at 13:27 -
-
tcpdump from tcpdump.org doesn't have
-nn
- either you specify-n
, in which case none of the conversions to names happens, no matter how manyn
s you have, or you don't specify it, in which case tcpdump tries to do all of the conversions. Perhaps the Red Hat/Fedora people hacked tcpdump to care how many times you specifiedn
.– user137177Oct 2, 2015 at 18:50