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Old 12-08-2009, 10:02 PM   #1
ubee
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persistent routing


hi,

why are the first 6 hops of the traceroute always the same no matter where i try to traceroute to?

i realize that things like gateways need to be persistent, but why 6 layers?
 
Old 12-08-2009, 10:13 PM   #2
nimnull22
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Because they are in your ISP network.
 
Old 12-08-2009, 10:17 PM   #3
SaintDanBert
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traceroute similarities

Quote:
Originally Posted by ubee View Post
hi,

why are the first 6 hops of the traceroute always the same no matter where i try to traceroute to?

i realize that things like gateways need to be persistent, but why 6 layers?
Most networks use one of the RFC "private IP address" ranges. One example is 192.168.1.0 thru 192.168.1.255. When you join such a network, you get an address using DHCP, say 192.168.1.200. Your access point needs to interact with your cable modem. This might involve a second private address, say 10.0.0.0 through 10.0.0.255. On the other side of the cable modem is another connection say 10.0.12.34. Only then will a public assigned IP address appear. Thus the first 3 or 4 addresses are likely to be quite similar. There are even decent odds that they will be almost identical.

~~~ 0;-Dan

NOTE
See http://www.faqs.org/rfcs/rfc1918.html for RFC details.
 
Old 12-08-2009, 10:24 PM   #4
bartonski
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Quote:
Originally Posted by ubee View Post
hi,

why are the first 6 hops of the traceroute always the same no matter where i try to traceroute to?

i realize that things like gateways need to be persistent, but why 6 layers?
I don't know about you, but it takes me 5 hops to hit anything beyond my ISP. My guess is that most of the routing is to get to and from long haul networks.
 
Old 12-09-2009, 12:46 AM   #5
ubee
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Quote:
Originally posted by bartonski

I don't know about you, but it takes me 5 hops to hit anything beyond my ISP. My guess is that most of the routing is to get to and from long haul networks.
on closer inspection, it is the 5th hop after my adsl router. not sure exactly how 'long haul' networks would require completely different ip ranges.

Quote:
Originally posted by SaintDanBert

Most networks use one of the RFC "private IP address" ranges. One example is 192.168.1.0 thru 192.168.1.255. When you join such a network, you get an address using DHCP, say 192.168.1.200. Your access point needs to interact with your cable modem. This might involve a second private address, say 10.0.0.0 through 10.0.0.255. On the other side of the cable modem is another connection say 10.0.12.34. Only then will a public assigned IP address appear. Thus the first 3 or 4 addresses are likely to be quite similar. There are even decent odds that they will be almost identical.
actually, there are 5 persistent hops after my public address, one of which (3rd, possibly Cisco) often reads in excess of 350ms delay. also, the last persistent hop doesn't return any information... i'm guessing that is the perimeter router.
 
Old 12-09-2009, 07:03 AM   #6
bartonski
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Quote:
Originally Posted by ubee View Post
actually, there are 5 persistent hops after my public address, one of which (3rd, possibly Cisco) often reads in excess of 350ms delay. also, the last persistent hop doesn't return any information... i'm guessing that is the perimeter router.
Go ahead and post the traceroute here. Use [code][/code] tags around the body of your traceroute, and obscure any IP addresses which might lead the world back to your door.

If there's a cisco router on your ISP's network that's introducing 350 ms latency, they need to fix that... and if there's a router upstream from them that's doing that, they need to be making some phone calls themselves. If you call your ISP, make sure that the call gets escalated to someone who will actually understand what you're talking about, and can actually do something about it... the front line tech support is usually working off of a script which involves rebooting your computer, unplugging your {cable,dsl} modem for 30 seconds, then bringing devices back on line one step at a time. If you're lucky, you may get someone who understands the basics of networking, The best compromise that you're likely to get from tier 1 is to have you email your traceroute to the ISP's tech support address, where it might get picked up by a tier 2 tech immediately. This is the sort of problem that's going to require both patience and pushing, knowing when, and to whom to apply pressure is a bit of an art form.
 
  


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