Linux - NetworkingThis forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.
Notices
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Get a virtual cloud desktop with the Linux distro that you want in less than five minutes with Shells! With over 10 pre-installed distros to choose from, the worry-free installation life is here! Whether you are a digital nomad or just looking for flexibility, Shells can put your Linux machine on the device that you want to use.
Exclusive for LQ members, get up to 45% off per month. Click here for more info.
I am using traceroute for the first time and having no success and need some help. The output from traceroute is basically
traceroute to www .google. com (66.102.9.104), 30 hops max, 40 byte packets
1 192.168.0.1 0.497 ms 0.506 ms 0.596 ms
2 * * *
3 * * *
4 * * *
5 * * *
6 * * *
7 * * *
etc.
My network is setup using a standard Ethernet card on my SUSE 9.1 machine connected to a Netgear DG814 ADSL Modem/router. I am using DHCP for IP address allocation and using bog standard BT broadband with a dynamic IP address.
Is it my config or is something else amiss
I have no problem connecting to the Internet and was looking at traceroute purely from a learning perspective and not to solve a current network issue.
ps. I have also tried xtraceroute with the same result
Traceroute may be blocked in your network. Does ping work (ping www.google.com)? Probably both ping and traceroute are blocked. Or it may be just your own firewall, if you have one.
PING www. google. akadns. net (66.102.9.99) 56(84) bytes of data.
64 bytes from 66.102.9.99: icmp_seq=1 ttl=240 time=45.1 ms
64 bytes from 66.102.9.99: icmp_seq=2 ttl=240 time=44.2 ms
64 bytes from 66.102.9.99: icmp_seq=3 ttl=240 time=44.1 ms
Because the first route outside works fine it has nothing to do with traceroute being blocked on your end.
Read up on what traceroute does it may help you.
What happening is that there is a time allocation for how long a router has to respond some routers are busier than others.
by default i believe trace route will wait 5 seconds before sending out the next packet mean one of three things if the resulting router did not respond.
1.) A router on the path not sending back the ICMP "time exceeded" messages
2.) A router or firewall in the path blocking the ICMP "time exceeded" messages
3.) The target IP address not responding
Routers can be configured to do this because it makes for less load on the routers.
so just dont worry about it there is nothing wrong with your network.
I trawled the web for any more clues and it seems that it is the UDP protocol that could be to blame. traceroute on Linux uses UDP by default while tracert on windows uses ICMP by default.
I ran tracert on my windows machine and it works.
Only problem I have now is trying to get traceroute to use ICMP instead of UDP.
none of these iterations work
traceroute -I www.google.com
traceroute -I ICMP www.google.com
traceroute -I icmp www.google.com
I dont see why traceroute -I <destination> shouldn't work because then it switches to icmp packets
but you can also try this program tcptraceroute its seems to be pretty good at gettings past most firewalls.
LinuxQuestions.org is looking for people interested in writing
Editorials, Articles, Reviews, and more. If you'd like to contribute
content, let us know.