Ping replies once but never again???

scarfies · #1 (**permalink**) 10-12-2004, 06:01 AM

This has to be one of the weirdest problems I've come across.
I'm on a far off node on our L3 wireless network and basicly whats happening is I can ping a node anywhere else on the network, it will reply once then timeout??
Internet IP's are usually ok but mostly its nodes on either the same subnet or a closeby subnet that have this issue, if I ping another address it also replies once then times out and remains unreachable until I change my IP or reset the interface.

Weird.
Is this an ARP issue or maybe MTU?

I'm a bit lost.

whetu · #2 (**permalink**) 10-12-2004, 10:28 PM

I'd say fire up Ethereal and see if it can reveal anything... perhaps there's some ICMP blockage going on somewhere? People tend to like using ICMP blocking/stealthing in the name of security, despite the fact that (speaking in internet terms) it's required and not a huge security threat. All it does is lets someone know you're there...

scarfies · #3 (**permalink**) 10-12-2004, 10:34 PM

yeh its all IP, not just ICMP, its like not enough signal or something, maybe its just that

Trvln Nalzmn · #4 (**permalink**) 10-13-2004, 03:05 AM

It shouldn't be MTU if some traffic is getting through. If you reset the interface and it starts working again I'd say that its a local machine issue. Try whetu's suggestion and put Ethereal on the machine. What would also help is if you put it on the machine you are trying to ping to see if the packet gets there.

Warwaste · #5 (**permalink**) 01-09-2005, 09:16 PM

Some suggestions here

You can set the number of times a machine is to ping and reply to pings. Setting a machine to only reply once will save on system bandwidth, but limits the accuracy of the QOS. It also frees up system resorces as a ICMP request takes presidence over other data (If I remember rightly from my learnings correct me if im wrong).
When you send a packet depending on the intelegence of a switch/router it will route your data the quickest way depending on network traffic on different lines. You could be being redirected through a router which has security issues.

Assumptions.
That you are using a windows environment.
That you are using a class C network with muliple routers or switches.
That you are using a mesh topology for your wireless network.
That you are using all hardware switches or routers

Try a tracert to the destination address.
Try dissabling firewalls.
Try a different sized ping packet.
Try chaning the number of pings to one. Then see if you can do that muliple times.
Check that no other machine on the network has the same IP address as you.
Try using a dhcp server to set all IP addresses on your network.
If you are using a software switch or router check that it is configured properly (They through up some weird resaults when you put two DHCP servers on the same network).
Check what protocols and protocol services you have installed.
Check that AP/Switchs/Routers are set to foward ICMP otherwise that can lead back to a bounce back (hardware dependant).
Make sure you are using the correct ping packet size as if you are over sizing the paket a firewall will detect it as a Ping of death and block you.

It sounds like a firewall is blocking your ICMP, but then if it was going to block it it wouldnt let the first ICMP AK back. Then if you cant ping after that its blocked your IP address.

If you are running a linux/other system please post so and I can give you some suggestions for that.

Hope this helps