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trumee
Guru
Joined: 02 Mar 2003
Posts: 551
Location: London,UK
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 Posted: Thu Jul 17, 2003 11:37 pm Post subject: What ip address is that ? |
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We are a running a computational cluster connected to several internal nodes. Doing a netstat brought this
#netstat
udp 0 0 math.beowulf.clus:32778 239.2.11.71:8649 ESTABLISHED
math.beowulf.clus is our server name, but where the hell is 239.2.11.71 is coming from. ping/nslookup donot give any replies to this ip address!!
Is there some way i can kill this process? or find out what is going on?
Thanks a lot |
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trumee
Guru
Joined: 02 Mar 2003
Posts: 551
Location: London,UK
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| Posted: Fri Jul 18, 2003 12:04 am Post subject: |
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| Well, i found out that this ip address was in our cluster monitoring programs(gangalia). However i still cannot ping to this address?? |
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devon
l33t
Joined: 23 Jun 2003
Posts: 943
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| Posted: Fri Jul 18, 2003 1:08 am Post subject: |
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Perhaps the admin of that box turned off ping?
| Code: | # sysctl -a | egrep icmp_echo_ignore_all
net.ipv4.icmp_echo_ignore_all = 0
# ping 127.0.0.1
PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data.
64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.051 ms
64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.006 ms
--- 127.0.0.1 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 999ms
rtt min/avg/max/mdev = 0.006/0.028/0.051/0.023 ms
# sysctl -w net.ipv4.icmp_echo_ignore_all=1
net.ipv4.icmp_echo_ignore_all = 1
# ping 127.0.0.1
PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data.
--- 127.0.0.1 ping statistics ---
2 packets transmitted, 0 received, 100% packet loss, time 1011ms |
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nbensa
l33t
Joined: 10 Jul 2002
Posts: 799
Location: Buenos Aires, Argentina
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| Posted: Fri Jul 18, 2003 2:05 am Post subject: |
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| There are some reserved IPs. Try "ping 224.0.0.1" to see what I mean. Perhaps, 239.x.x.x belongs to some of those reserved addresses and can't be ping'ed? |
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devon
l33t
Joined: 23 Jun 2003
Posts: 943
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| Posted: Fri Jul 18, 2003 2:17 am Post subject: |
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| nbensa wrote: | | There are some reserved IPs. Try "ping 224.0.0.1" to see what I mean. Perhaps, 239.x.x.x belongs to some of those reserved addresses and can't be ping'ed? |
D'oh! Didn't even cross my mind.... trumee check out http://www.iana.org/assignments/ipv4-address-space -- In particular "239/8 Sep 81 IANA - Multicast". |
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Ian
l33t
Joined: 28 Oct 2002
Posts: 834
Location: Somerville, MA
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| Posted: Fri Jul 18, 2003 3:02 am Post subject: |
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isn't a first octet number that high reserved for research, or something crazy like that?
i did know this, but then summer came, and i forgot everything that i learned from my Cisco course. oh well, looks like I'll be reviewing a lot for my CCNA exam next spring... |
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think4urs11
Bodhisattva
Joined: 25 Jun 2003
Posts: 6659
Location: above the cloud
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| Posted: Fri Jul 18, 2003 12:25 pm Post subject: |
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it is a so called multicast address
that addresses are from 224.0.0.0 - 239.255.255.255
in your case it is
239.2.11.71 --> the default multicast channel for gmond to send/receive data
and yes, AFAIK it is correct that these addresses aren't pingable at all.
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Nothing is secure / Security is always a trade-off with usability / Do not assume anything / Trust no-one, nothing / Paranoia is your friend / Think for yourself |
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