Ping is a mechanism to see if a remote host is reachable via an IP network

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1answer
456 views

Does Linux support IPv4 mapped IPv6 addresses?

I work in a mixed IPv4 / IPv6 environment. I read that IPv4 addresses can be mapped into the IPv6 space with this syntax ::ffff:1.2.3.4 (1.2.3.4 is the IPv4 address) Does Linux support this ...
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4answers
5k views

Linux router: ping doesn't route back

I have a Debian box which I'm trying to set up as a router and an Ubuntu box which I'm using as a client. My problem is that when the Ubuntu client tries to ping a server on the Internet, all the ...
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2answers
11k views

Can ping IP address and nslookup hostname but cannot ping hostname

On a windows 2003 server I can nslookup www.google.com which returns Server: localhost Address: 127.0.0.1 Non-authoritative answer: Name: www.l.google.com Addresses: 74.125.79.104, ...
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1answer
2k views

2 router network setup. Why does ping only work in one direction?

So the setup looks like this: There is a main WLAN-router/modem which is connected to the internet and serves the lower floor with WLAN. Now upstairs I have a second WLAN-router/modem (I will call it ...
0
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1answer
172 views

Branch to Branch VPN through HQ router?

I've just upgraded our router and am working my way through setting it up as the old one was. The new router is a Draytek Vigor 3900. We have a number of sites with IPSec tunnels dialling in to our ...
2
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1answer
782 views

OpenVPN and one way pings

Network configuration I have set up a network: Appropriate ports of computers in 192.168.87.0/24 are forwarded on TP-LINK router to be seen "all over the world". IP forwarding in enabled on ...
0
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1answer
275 views

Cisco ASA failover can't ping gateway

I'm currently trying to set up a failover network for my Cisco ASA 55x0 using the SLA traking. I have the "outside" interface (network 89.x.x.48/29) and the "outside2" interface (network ...
0
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1answer
378 views

Hamachi gateway PC responds when pinging remote PCs from internal network

We are using Hamachi to link 2 remote sites together via a gateway VPN network. This generally works fine. At our main office, our SBS 2003 server acts as the DHCP server. The Hamachi gateway client ...
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2answers
213 views

Win 7 Netbook refuses to ping JetDirect card (all other PCs work)

I have an odd thing occuring here. From a Windows 7 netbook, I cannot ping an HP printer on the network, while all other machines (Win7/Vista) can. And the netbook can also ping everything else on the ...
0
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1answer
1k views

I cannot ping my guest operating systems via Bridged Network Connection

Here are the details: I am using VMWare Workstation 9.0.1 build-894247. Host - Windows 7 - Firewall is turned on - has static IP Guest OS 1 - Windows Server 2008 R2 - Firewall is turned off - has ...
0
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1answer
940 views

unable to access a NAT'ed IP via a VPN on Windows 7

I connect to a range of servers hosted by one provider via a VPN. I can connect to the VPN fine, however when I then go and try and connect to the server(s) it fails. A NAT'ed IP address that has ...
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3answers
4k views

nslookup fails but ping succeeds for nonexistent domains

I have two different FreeBSD servers (different hosting companies), both exhibit this same behavior: They pick a specific IP address (216.239.120.238) for every domain that does NOT exist. nslookup ...
2
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1answer
295 views

Server responds to pings but no SSH or HTTP access

I do not know what has caused this but my websites have been down for 2+ days now and I cannot connect via SSH or FTP either. The only way to get signs of life from my server is to reboot it via the ...
0
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1answer
174 views

35 times increased latency between data send rate of 1 millisecond vs 100 microseconds. WHY?

Experiment hping -S --data 100 -c 100 10.56.1.2 -i u100 round-trip min/avg/max = 0.5/14.0/15.8 ms hping -S --data 100 -c 100 10.56.1.2 -i u1000 round-trip min/avg/max = 0.3/0.4/4.8 ms Observation: ...
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2answers
3k views

Windows Server 2008, can't ping, but networking is fine

I'm setting up a Windows Server 2008 box, and everything is working great (database, remote login, etc.), but it doesn't respond to ping. Normally I might not care, but I'm setting up Nagios ...
0
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3answers
367 views

Why can't I ping my freshly set up amazon web service EC2 instance?

I was following this tut on how to set up a EC2 instance on Ubuntu but qhen trying to execute ssh command on my IP address, I had an operation Timeout. So I tried to ping it but no chance neither. ...
0
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1answer
207 views

Can't ping6 a network interface from a different Ubuntu computer

I cannot ping6 the network interface "tun0" on the host computer from a virtual machine. Using vmware, I installed a Ubuntu 12.04 virtual machine, that is connected to the host machine with NAT. ...
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2answers
2k views

Linux ping command exits early due to ICMP host unreachable

An automated script runs shutdown -r now on a machine, and after a 30s delay, uses ping to determine when the machine is available. I've recently switched the OS from Centos 5 to Oracle Linux 6 and ...
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0answers
140 views

One way ping on an embedded Linux system

I'm facing a networking issue with an embedded Linux system in a private network. We have a network that consists of a few tens of servers connected through a switch with one of the servers acting as ...
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2answers
3k views

Fragmentation and packet size,using tcpdump

i am trying to understand concept of fragmentation: i have two virtual machines with public ip connected to a switch. tracepath shows packet not going through gateway from vm1: Trying to send ...
0
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2answers
158 views

How do know if I can SSH in servers?

I have over 200 servers, but is hard to keep tracking all of them by some documents, after a while it gets outdated, so to refresh this document, I have to know which servers I can login via SSH. I ...
0
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1answer
218 views

Hping showing -400% packet loss

I used the following command: sudo /usr/sbin/hping3 -q -n -c 5 -S <hostname> -p 8080 and the output I got is: 1 packets transmitted, 5 packets received, -400% packet loss Can you please ...
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2answers
966 views

Why would ping give me fast rtt values, but take a long time for each response to come back?

I've got a bit of a basic networking question here regarding ping. When pinging a particular host on a completely different subnet, I get a response like this: PING myhost.example.com (1.2.3.4) ...
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0answers
948 views

Unable to ping vmware-workstation guest from host

Using vmware-workstation 9 Host OS win8 x64 IPv4 address: 192.168.0.101 Guest OS winxp x86 IPv4 address: 192.168.0.106 The same thing happens with NAT and bridged for the guest vm. I am able to ...
0
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1answer
41 views

Ping Interconnected PCs End-To-End

I have the following network topology: [PC 1] - - - [PC 2] - - - [PC 3] - - - [PC 4] Each machine is connected via a crossover cable. I can ping from PC 1 to PC 2, but how can I configure things so ...
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1answer
326 views

openvpn (tun0 + bridge) : Comunication bridge --> tun0 works but not the opposite direction

My network is composed as follows: Host A with ip 9.x.x.x and vpn ip 192.15.206.x (openvpn client) Host B with ip 9.x.x.x and vpn ip 192.15.206.1 (openvpn server) this host has a bridge br0 with ip ...
0
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1answer
175 views

Can't establish connection between my VPS and itself

I have a VPS with two IP addresses: 74.117.158.92 and 74.117.159.204. If you ping them, you'll find they are both responding. I can also ping google.com etc. from either of them. But I cannot ping ...
0
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1answer
173 views

debian clients connected to the same switch, ping problems

I have two machines that are connected to the same switch. Machines have multiple ethernet interfaces connected to the different networks. Computer A can ping an antenna which is connected to the same ...
0
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1answer
74 views

Linux server responds to postgresql querys and ssh only when pinging the server

I have a problem. My developers are using one of my local servers that is located in our office. The server is running PostgreSQL and when they try to make a query to it, it just lags and then gives ...
0
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4answers
170 views

Is asymmetric latency common in practice?

This is a follow-on to a question posted on stack overflow about whether it is possible to determine the one-way latency of a point to point connection without using externally synchronized clocks - ...
0
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1answer
101 views

Is it worth to set up a different network interface for connections to MySQL?

I have a high load website served by two servers: web server with nginx and php, and database server with mysql. Web server serves all the static content and connects to MySQL and outside world ...
0
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1answer
58 views

Unable to reach Terminal Apps and Ping to VM server 2008

We have Domain Controller Group Policy Set to Disable Firewall on All computers within Domain, because we have Syamntec end point Protection enabled. The problem now is, since Windows Firewall is ...
0
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1answer
2k views

Hyper-V VM guest can't ping any machine

So I got Host: Hyper-v enabled machine with four NICs, only one enabled. Network type: External IP configuration are correct for both host and guest (getting it from the DHCP of the company network) ...
0
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3answers
100 views

Reverse dns returns a different host each time

So, randomly I happened to ping abc.com and found this fascinating: $ ping abc.com PING abc.com (199.181.132.250) 56(84) bytes of data. 64 bytes from m.abc.com (199.181.132.250): icmp_req=1 ttl=237 ...
0
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1answer
116 views

Best practices on lowering latency between two endpoints [duplicate]

I would like to know what tools or what kind of calculation should be made in order to find the lower latency possible between two points physically distant. For example: Ping time from Europe to ...
0
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2answers
78 views

Will I get banned or blocked for running a diagnostic app?

This may seem like a simple question. Hopefully it will have a simple answer. I run an internet radio station. There are 3 machines. Music source client Stage server Master server (relays the ...
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0answers
220 views

How to interpret traceroute with success on some routes and failing on other similar routes?

I have traceroute paths from 3 unique source hosts, to a single destination host (173.254.24.18). The final results of these three routes are including similar elements, and yet the final failing ...
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2answers
157 views

Nmap scans the host but cannot ping the host [closed]

My laptop is connected to a network where we have routers with filters. I can use nmap to scan alive hosts and I can see open ports (mostly port 80). But then, when I try to ping those hosts, I dont ...
0
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3answers
614 views

NSLOOKUP and NBLOOKUP give one IP address; PING finds another

In a Windows Server 2008 domain the on-site domain controller serves as both DNS and WINS server. It is also a DHCP server. One workstation is used as a platform for all admin of the various servers ...
1
vote
1answer
248 views

IPv6: ping6 from foreign host works, but cannot ping6 on same host [ubuntu 12.04]

I have a strange issue with ipv6 on Ubuntu 12.04. There are two hosts, directly connected to the internet. Both have assigned a /64 network. They are properly configured with a /128 endpoint each and ...
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2answers
535 views

ping -R and traceroute mismatch

I am stuck at a very strange result after running the command ping -R in a unix environment. To be more specific, I am trying to follow the path to a server and back but there is quite a mismach ...
0
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1answer
105 views

Ping sometimes resolves the name, sometimes not

Is this a normal behavior, that ping sometimes displays the server name, sometimes only the IP? OS: Ubuntu 12.10 ~# ping development.example.local PING development.example.local (192.168.0.25) ...
0
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1answer
763 views

Cannot Ping or Resolve DNS Internally; Externally works fine

I have an issue where I cannot seem to access a subdomain from within the same server: I can ping, nslookup, etc subdomian.domain.com externally, but from within the server where subdomain.domain.com ...
4
votes
1answer
320 views

tcpdump on interface when pinging nonexistent hosts on local network

I've statically configured the IP address of an interface on a server: ip addr add 10.40.0.6/16 broadcast 10.40.255.255 dev eth1 If I try to ping a machine on the network (e.g., 10.40.0.1), it ...
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2answers
501 views

arp packet received larger than packet sent, why?

I'm trying to debug a networking issue. During this process, I've noticed that when I try to do an arping, the received arp packets are larger than sent arp packets, as outputted by tcpdump. (Note ...
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6answers
24k views

Enable Ping in Windows Server Firewall?

I've just installed Windows Server 2008 on a server and I'm able to connect through Remote Desktop but can't ping. Do I need to open an special port on the firewall to be able to ping a server?
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2answers
199 views

ping and identify Cisco model without physical access or login?

There are several Cisco devices on my network which I can find with ping or nmap but I have no idea what the type (e.g. switches, routers) or specific model is. Is there some way to find this out ...
0
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2answers
251 views

Can ping google.com, but can't ping cnn.com

I have just upgraded from 10.04 to 12.04. I didn't notice the problem at first. But when installing horde with the pear installer it failed to download all of the packages. So I did a little hunting ...
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1answer
767 views

ping -a does not return hostname [closed]

The problem i am currently experiencing is with One of my Untangle boxes. We are using IPsec VPN, Microsoft Server 2003 for DNS. I cannot get RDP to work with hostname, FQDN, ONLY IP. When i use ping ...
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1answer
2k views

Server can't ping or connect to self

This SF Answer helped me after nerve's answer below: No network loopback device after security update ubuntu 12.04 Original Question I've been Google-ing and banging my head against the wall for a ...