Networking :: Why Firewalls Does Not Allow ICMP Echo Request Packets
Feb 8, 2011Why firewalls does not allow ICMP echo request packets. Why are pings not allowed to certain systems?
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Ubuntu Networking :: Ping ICMP Warning - Duplicates Packets
Sep 28, 2010When I ping our Microsoft Windows terminal server "cluster" farm, I get ICMP warnings that there are duplicate packets. I am able to rdesktop to the cluster with no problems. We are trying to setup nagios to run on this Ubuntu configuration and nagios is reporting the following error:
"PING WARNING - DUPLICATES! Packet Loss=0%, RTA=.98ms.
FPing reports duplicates as well. Is there a setting in the Arp table that needs to be set differently because the "Cluster" MAC address isn't an actual hardware MAC but a virtual MAC address?
Ubuntu Security :: Configure Ufw To Drop Icmp Echo Requests?
Jul 12, 2010I've been trying to configure ufw to drop ping requests for a couple days now, and I can't figure it out. I've tried a couple different methods in some different guides, still nothing. Anyone know how to do this?
View 4 Replies View RelatedSecurity :: Racoon And Plain ICMP Packets?
Apr 6, 2011i have configured racoon (ipsec tunnel) between 2 hosts and i am afraid of unencrypted ICMP which appears in TCPDUMP logs. There ale also encrypted ESP packets. Is this result of wrong racoon configuration?
172.16.220.133
Code:
[root@localhost ~]# cat /etc/racoon/racoon.conf
# racoon.conf
path pre_shared_key "/etc/racoon/psk.txt" ;
remote anonymous
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Programming :: Make A Listener For ICMP Packets?
Oct 17, 2010I have a gateway server which is currently listening for TCP/UDP packets and authenticating clients if their details IP/MAC is known.
I have a couple of clients who's network equipment sends ICMP pings to a remote site to determine internet connectivity and I'm missing those resulting in the client's device not logging in.
Is there some way that I can write a listener similar to a listener for TCP/UDP sockets which will listen to ICMP packets and pick up the IP and MAC address of the sender upon which I can perform processing on?
General :: LAN Machines Sending Packets By Iftop - Set Only Send And Recieve Http - Smtp - Ssh - Dns - Dhcp Request?
Jun 10, 2011I have proxy running. I have seen LAN machines sending packets by iftop -P -F 192.168.10./24
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How do i set my iptables so that I can only send and recieve http,smtp,ssh,dns,dhcp request in and out of the proxy
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Networking :: Firewall - Allow Packets Coming From Internet After Authenticating And To By Pass Packets Generated From Internal LAN?
Feb 8, 2010i have a linux server runnig oracle applications. i need to access this server from putty using ssh through internet. i did by registering my static ip with the dnydns.org and i am able to connect to the server. but now there is no security to authenticate any user as any one knowing the password can login to it.
i thought of configuring the firewall of linux server but the client ip`s are not static and they change continiously. so thought of keeping one more pc between the server and the router which will do the work of authenticating. but i am confuse as how to configure it to allow the packets coming from the internet after authenticating and to by pass the packets generated from internal LAN?
Ubuntu Security :: UFW Block ICMP When Add Non ICMP Related Rule
May 21, 2011I am setting up a virtual server. Ubuntu 11.04, "minimal provider image".UFW was disabled by default. I set it to default deny. Allowed HTTP, SSH and other standard stuff, and enabled it. All seems to be OK. Adding one rule to block some annoying security scanners causes ping not to work. I'm not an Iptables expert, but it looks OK to me. I got it from some website, rather than invented it myself, but modified to to fit the ufw config file syntax. What in that rule prevents pings?!? It seems completely unrelated.
View 1 Replies View RelatedProgramming :: Write A Program In C That Can Sniff Packets From Ethernet And Distinguish RTP Packets From Non-RTP Packets?
Aug 30, 2010i need to write a program in c that can sniff packets from Ethernet and distinguish RTP packets from Non-RTP packets, i have no idea what should i do
View 9 Replies View RelatedUbuntu Networking :: No Incoming Connections When Firewalls Disabled?
Mar 13, 2010I'm using Linux Mint 8 KDE, which is essentially kubuntu karmic.
Been trying to set up bittorrent (tried several different apps), have followed all the usual steps, forwarded ports on both Guarddog and my router, but still no incoming connections. Then tried disabling the firewall in Guarddog - still no incoming connections. Never had any problems configuring my router before so can only think that there must be something else blocking ports in linux other than iptables.Also had same problem just using ufw and gufw
Networking :: Kernel - Forward Packets From Eth0 To Eth1 And Eth1-to Eth0 As Well As Get A Copy Of These Packets For Analysis
Sep 27, 2010I have a hardware device with two ethernet ports, eth0 and eth1 running Centos 5. Basically my goal is to forward packets from eth0->eth1 and eth1->eth0 as well as get a copy of these packets for analysis. If I set IP routing to do the forwarding then I won't get a copy of the packets for analysis.
View 3 Replies View RelatedGeneral :: $echo Cat Vs $cat Echo / Difference Between Them?
Dec 16, 2010What is the difference between
$echo cat
$cat echo
Networking :: Identify The Icmp Packet?
Dec 1, 2010how to identify the icmp packets & marking. this below icmp packets marking is not working.
iptables -t mangle -A PREROUTING -p icmp -j MARK --set-mark 0x5
iptables -t mangle -A PREROUTING -p icmp -j RETURN
with the help of port no or any other how can i identify the icmp packet ?... This below two is working fine
iptables -t mangle -A PREROUTING -p tcp -j MARK --set-mark 0x2
iptables -t mangle -A PREROUTING -p tcp -j RETURN
iptables -t mangle -A PREROUTING -p udp -j MARK --set-mark 0x3
iptables -t mangle -A PREROUTING -p udp -j RETURN
Networking :: ICMP Got Lower Priority?
Mar 16, 2010I run a linux box as a gateway behind a satellite modem. The internet link over the satellite modem is only 1mbit so the usage often reaches 100% when someone is downloading/uploading something. I am seeing my ping return time jump from 700ms to 6000ms if someone tries to upload a file (by sending a attachment in a email etc). The satellite operator is saying this is normal, but I have my doubts.
Has ICMP got a lower priority? Should I really be seeing this behaviour? I understand that if it was a TCP packet then it would just be queued until the previous acknowledgement has been received. And if it was a UDP packet then it would have been dropped, but how does ICMP deal with these situations during heavy traffic?
Networking :: Set ICMP TTL Exceeded Host?
Feb 20, 2011Is there a way to set the IP that's returned in an ICMP TTL exceeded packet? Reason I ask is I have an edge router with several upstreams, and several downstream routers, and when I traceroute to it I would like only one of it's IP's to show up in the trace (Instead of each . Much like some of the larger ISP's do to mask the IP and hostname of their internal routers.. Is this possible?
View 2 Replies View RelatedNetworking :: Possible To Block ICMP To Particular Machine?
Jan 12, 2010I have One Server which is having IP 10.176.0.155. I want that client 10.176.0.135 is not able to ping this server only & cane it is possible to block through hosts.
View 1 Replies View RelatedNetworking :: Why Linux Traceroute Use UDP Instead Of ICMP?
Jun 22, 2010Why linux traceroute uses UDP protocol, we have basic ICMP protocol which is used in MS-windows tracert.Any specific use of traceroute using with UDP,TCP than ICMP?Windows is displaying all HOPs address but linux printing *.*.*
View 8 Replies View RelatedNetworking :: How To Receive ICMP Messages In UDP Sockets
Jul 9, 2009I have a C program which does.
1. Creates a UDP socket
2. Send the UDP Request packet to the TFTP server.
3. If the TFTP server is not listening in the 69 port, the remote machine send an ICMP ("Port Unreachable") message.
Is there a way to receive a notification from the Linux kernel on receipt of an ICMP packet to the created UDP socket.
Networking :: ICMP Response Not Sent To A Local Network Ip?
Aug 19, 2010icmp request from an ip that is in the same network as one of the local interfaces is not responded to, if the ping request is received via an interface in a different network. Is this some security feature?
Consider the below network
x.1|RTR1|-y.1---------y.2-|RTR2|-z.2------z.3-|LNX|-x.3
RTR - Router
x.1 -> 192.168.x.1
LNX - Linux machine
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Networking :: Get An Icmp Tunnel Setup Using Ptunnel
Jul 23, 2011So im trying to get an icmp tunnel setup using ptunnel. When I run it under the same network and use to connect to RDP, it works fine, however when go outside my network and connect in, it does not get anywhere. I can confirm that I have forwarded ICMP packets to the server (if I ping the external ip it will show the status of the server if I unplug it) and that the server is showing signs of registering it.
On the client it just tries to resend the packet "Resending packet with seq-no 0" Over and over Firewall is off for testing so thats not the issue.
Fedora Networking :: ICMP Redirect From Windows Gateway...
Sep 10, 2009From what I've read, when linux sends a ping it sends without the netmask, so windows server assumes it must be a broadcast? Why doesn't linux send a netmask with a ping?
View 6 Replies View RelatedUbuntu Networking :: Nmap Ping A Pc With Icmp Disabled?
Nov 13, 2010I tried to ping some of the pcs on the local network but for those with icmp disabled it doesn't work. I've used
Code:
nmap -sP 192.168.2.0/24
Ubuntu Networking :: Server Block ICMP By Default?
Jan 8, 2011Installed Ubuntu Server 10.10, included Apache, PHP, and OpenSSH. Apache is up and serving pages, I can connect using PuTTY no problem. Server responds to a pingHowever, attempting to use ping or traceroute from the server results in a Destination Unreachable. Happens even for other 192.168.1.10x boxes on the local network
View 1 Replies View RelatedNetworking :: Need ICMP / SNMP Based Monitoring Tool
Apr 21, 2010Can any one tell me a network monitoring tool which can monitor remote connectivity and generate a comprehensive report about the link state like up/down, error timings, increase in latency and packet loss rate.
View 3 Replies View RelatedNetworking :: Relay Raw ICMP Packet To Local Destination
Feb 21, 2011On my system, I have built my own tunneling protocol, where I relay packets over a non-standardized but verified medium. What I do is capture the packets using iptables and NFQUEUE, relay them over my medium, and at the other end I reinject them using raw sockets. The packet going into the tunnel is exactly the same as the one coming out, verified. The problem is that this doesn't work for ICMP Ping (Echo Request) if the destination of the ping is the same as the tunnel endpoint. If the destination is not the same as the tunnel endpoint, the ping packet is rerouted and arrives as it should at the receiver, and the ping reply comes back to the sender. Does anyone know whats going on? Isn't it possible to send raw icmp to yourself? If not, anyone have an idea what I should do instead?
View 1 Replies View RelatedUbuntu Networking :: Disable ICMP Router Discovery For IPv6?
Jan 14, 2010I set up a static IPv6 address and a gateway in /etc/network/interfaces. However, a bad router in my network environment alway send wrong ICMP router discovery messages to me. So I have got extra (wrong) IPv6 address and gateway, and the routing is confused. On Windows Servers, I can use "netsh interface ipv6 set interface "Local Area Connection" routerdiscovery=disable" to disable ICMP router discovery. But I don't know how to disable it on Ubuntu 9.10. How could I disable ICMP router discovery for IPv6?
View 4 Replies View RelatedNetworking :: Accept ICMP Redirects Not Originating From Default Gateway
Mar 9, 2011Struggling to get my Linux server accept ICMP redirects not originating from default gateway. No problem to get it working if the redirects is originating from def gw.I know it's not a good solution security wise, but my network is so cluttered I'm forced to do so.
View 1 Replies View RelatedCentOS 5 Networking :: ICMP Ping Latency Grows Over Time
Apr 20, 2011I have a dedicated host on my lan to monitor other hosts/services using Nagios. I'm in the process of migrating to Zabbix on that host to perform the same purpose. Both Nagios and Zabbix monitor icmp ping latency (Nagios uses ping, Zabbix uses fping) and over time the latency to other hosts grows until threshold alarms are triggered. In one week, the average latency grows from sub-millisecond to over 100 milliseconds, and continues to grow until the Nagios host is rebooted. I have verified the latency numbers using ping/fping from the command line on the Nagios host.
The problem is that pings from the monitored hosts to the Nagios host show normal latency at the time the Nagios host is showing high latency from itself to the monitored hosts. The Nagios host and monitored hosts are all connected to the same Dell 24 port gigabit switch. I already posted this question on the Zabbix forums with a graph of the latency but there were no answers. [URL] why the icmp ping latency is growing over time and how I can fix it short of rebooting the host on a schedule.
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Server :: Redirect All Client Http Request To Https Request In Squid?
Jun 25, 2010how to redirect all client http request to https request in squid
View 1 Replies View RelatedUbuntu :: IPtables And UFW - Same Or Two Different Firewalls
Aug 27, 2009I'm new to Ubuntu and Linux and still trying to figure things out. Are UFW and iptables the same, or are they two different firewalls? The reason I ask this is that I can load up Firestarter, (which, from what I've read controls iptables), then go into a terminal mode and run "ufw status", and it shows disabled. What I'm ultimately trying to do is to open up a port so Vuze and/or Transmission Bitorrent will work, but have not had any success.
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