Sponsored Content
Full Discussion: What arp -s is good for
The Lounge War Stories What arp -s is good for Post 302719647 by Corona688 on Monday 22nd of October 2012 07:11:36 PM
Old 10-22-2012
What arp -s is good for

A customer appears to have drastically misunderstood our instructions for connecting to our WAN. He set his PC IP address to the same as one of the bridges. Smilie Smilie This caused much confusion on the network, to put it mildly. He called to complain about the poor performance of the network he ruined, then made himself unavailable for phone calls so it couldn't be fixed.

Even blocking his MAC address didn't help. The bridging problem happens in midair, nowhere the server can control. If I could at least get into the bridge, I could reconfigure it to a different IP and allow traffic again...

So, on the server, I tried this:

Code:
arp -d 192.168.6.101 ; arp -s 192.168.6.101 00:60:b3:07:0e:8e

This succeeded in forcing the server to talk to the bridge, not to him. I was then able to get into the bridge's web interface and change its IP from there. From there it was easy.
These 5 Users Gave Thanks to Corona688 For This Post:
 

10 More Discussions You Might Find Interesting

1. Cybersecurity

ARP address resoluton

How does ARP take care of uniqueness of physical addresses? How does an ISP allocate a MAC address when I do not have an NIC( Network interface Card)? (1 Reply)
Discussion started by: ManishSaxena
1 Replies

2. Solaris

ARP Cache

Dear all, We are testing two of our servers for mq series connectivity. The scenario is, when one machine is shutting down it's services there are some scripts that do a dns update, which removes the ip address and relates it to the ip address of the other node on our dns server, and the update... (7 Replies)
Discussion started by: earlysame55
7 Replies

3. IP Networking

ARP Req Pkt

Does ARP Request packet Contains MAC Address of dest during broadcast? I found It So... When i captured ARP Req Pkts on ethereal... Rgds -Meti (1 Reply)
Discussion started by: ashokmeti
1 Replies

4. HP-UX

HW Address and arp

I was checking nettl output for a unstable telnet to my server. this is part of output: ### ***********************************STREAMS/UX*******************************@#% Timestamp : Sun Jun 22 EETDST 2008 22:14:47.492899 Process ID : Subsystem ... (4 Replies)
Discussion started by: xramm
4 Replies

5. IP Networking

arp output (flags)

I'm running an arp -an on a Solaris 10 box. We're using IPMP. One of the systems is not able to see a host on the same network. The only difference between the two systems (one is having a problem, the other isn't) at least so far is the output of arp: # arp -an | grep 224.55 e1000g5... (1 Reply)
Discussion started by: BOFH
1 Replies

6. Red Hat

Arp Problem

Dear All i have a linux proxy server which has RHEL-5 64 bit, it has two interfaces, it has the following details eth0=10.200.14.42 eth3=10.201.14.42 default gateway=10.201.14.254 one static route=192.168.0.0/24 gw 10.200.14.254 i am facing a problem when i ping 10.201.14.42 from... (2 Replies)
Discussion started by: surfer24
2 Replies

7. IP Networking

Stuck ARP entries

About a week ago a customer hooked up a wireless router backwards to our network, causing it to serve incorrect DHCP addresses to some of them. Our networks are mostly statically assigned so this didn't cause as much damage as it might have, but now, over a week later, I still have incomplete... (1 Reply)
Discussion started by: Corona688
1 Replies

8. UNIX for Advanced & Expert Users

arp questions

Can someone please explain this output to me. Why doesn't ifconfig show the same info? ~ $ arp -a ? (10.71.0.1) at 00:1b:21:2b:eb:0c on eth0 (4 Replies)
Discussion started by: cokedude
4 Replies

9. IP Networking

Protection against arp spoofing

Hi, I'm trying to find a way to protect my network against arp spoofing. What it is: An attacker sends fake arp packets in the network, identifying himself as the router. All network traffic is then redirected to this attacker. How to protect myself: In my opinion, the best possible... (2 Replies)
Discussion started by: chrisperry
2 Replies

10. IP Networking

necessary ARP request?

Hello, I have 2 clients with Unix installed. host1: eth0 (192.168.5.10) & eth1 (192.168.10.10) host2: eth0 (192.168.10.20) I've connected host1-eth1 to host2-eth0. host1-eth0 isn't connected. I started 'tcpdump' on wonder that host2 got ARP requests for 192.168.5.10. Any idea why host1... (2 Replies)
Discussion started by: daWonderer
2 Replies
IFNDP-PROXY(5)						       Network configuration						    IFNDP-PROXY(5)

NAME
ifndp-proxy[-<interface name>] - IPv6 NDP and IPv4 ARP proxy entries SYNOPSIS
/etc/sysconfig/network/ifndp-proxy /etc/sysconfig/network/ifndp-proxy-<interface name> DESCRIPTION
These files contain IPv6 NDP and IPv4 ARP proxy settings, that should be applied using the ip neigh add proxy command documented in the ip(8) manual page that provides a common interface for IPv4 and IPv6. The NDP/ARP proxy is required, e.g. when IP addresses from the same subnet have to be used on the interface of the host as well as on interfaces behind a (tunnel) interface and using a bridge is not an option. Don't forget to enable forwarding and the NDP/ARP proxy by setting net.ipv6.conf.<all|default|interface name>.proxy_ndp = 1 net.ipv6.conf.<all|default|interface name>.forwarding = 1 and/or net.ipv4.conf.<all|default|interface name>.proxy_arp = 1 net.ipv4.conf.<all|default|interface name>.forwarding = 1 or net.ipv4.ip_forward = 1 either as global all setting in the /etc/sysctl.conf file or using the ifsysctl(5) files, that allow per-interface setup. Forwarding can be also enabled in the /etc/sysconfig/sysctl file using the IP_FORWARD and IPV6_FORWARD variables. The proxy entries are added and deleted using the if-{up|down}.d/ndp-proxy script, every time after an involved interface has been set up or down. SYNTAX
The format of the ifndp-proxy file is: <address> <address interface> <proxy interface list> The format of the ifndp-proxy-<address interface> file is same to above, but allows also to omit the address interface by using a "-" as placeholder inside of the file, because it is already available in the file name: <address> <address interface | -> <proxy interface list> Lines beginning with # and blank lines are ignored. Each line defines to add a proxy NDP/ARP entry with the address of or behind address interface to all interfaces in the proxy interface list. EXAMPLES
Let's assume, your machine is connected via eth0 to a switch with the networks 2001:db8:abba::/64 and 192.168.100.1/24 and is using the IP address 1 itself. You'd like to use the addresses 11 and 12 e.g. for virtual machines behind the tap1 and tap2 interface, that is: 2001:db8:abba::1/64 -- local eth0 address 2001:db8:abba::11/64 -- address behind tap1 2001:db8:abba::12/64 -- address behind tap2 192.168.100.1/24 -- local eth0 address 192.168.100.11/24 -- address behind tap1 192.168.100.12/24 -- address behind tap2 then set up the following entries in the ifndp-proxy file: 2001:db8:abba::1 eth0 tap1 tap2 2001:db8:abba::11 tap1 eth0 tap2 2001:db8:abba::12 tap2 eth0 tap1 192.168.100.1 eth0 tap1 tap2 192.168.100.11 tap1 eth0 tap2 192.168.100.12 tap2 eth0 tap1 additionally to the routing entries in the routes or ifroute-<interface name> files. BUGS
Please report bugs at <https://bugzilla.novell.com/> AUTHOR
Marius Tomaschewski <mt@suse.de> SEE ALSO
ifup(8) ifcfg(5) ifsysctl(8) sysconfig December 2009 IFNDP-PROXY(5)
All times are GMT -4. The time now is 04:49 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy