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Old 06-05-2012, 07:52 AM   #1
ajo8
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tcpdump not listening on any other interface


Hi! On Fedora, I'm trying to get tcpdump to listen on other interfaces, besides eth0. I have a total of 6 (eth0-eth5). Whenever I specify an interface to listen on (e.g. tcpdump -i eth4), it will only listen on eth0 every time. Listening on 'any' interface yields the same results.

Last edited by ajo8; 06-05-2012 at 07:54 AM. Reason: spelling
 
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Old 06-05-2012, 09:24 AM   #2
grim76
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How are you determining that only eth0 is being used?

Code:
# tcpdump -i eth3
Excerpt from my /var/log/messages

Code:
kernel: device eth3 entered promiscuous mode
kernel: device eth3 left promiscuous mode
Please post exact commands used and output from logs. (Make sure to use code tags)
 
Old 06-05-2012, 10:12 AM   #3
ajo8
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command being used:
Code:
# tcpdump -i eth4
output:
Code:
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes
messages:
Code:
kernel: device eth0 entered promiscuous mode
kernel: device eth0 left promiscuous mode
 
Old 06-05-2012, 11:37 AM   #4
grim76
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Looks like there might be an alias at play. Try entering the full path to tcpdump.

Code:
/usr/sbin/tcpdump -i eth4
 
Old 06-05-2012, 11:54 AM   #5
ajo8
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That worked. Hm, where would this alias be defined? I checked /etc/profile and /etc/bashrc, as well as the local logins', but there's nothing referencing it.
 
Old 06-05-2012, 12:33 PM   #6
grim76
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alias -p should list your aliases. You might also check .bash_profile .bash_rc.
 
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Old 06-05-2012, 01:33 PM   #7
ajo8
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Thanks so much! That solved it.
 
Old 06-05-2012, 09:19 PM   #8
KinnowGrower
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ajo8,

Can you please "show" What was alias ? and in which file it was defined?. It will help others as well.

Thanks

Last edited by KinnowGrower; 06-06-2012 at 09:53 PM.
 
  


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