Strange Filtering by ISP

robroy22 · 02-22-2007, 01:46 AM

Basically what happens is that tracert (and ping) runs just fine if the dest ip is < 36.x.x.x and seems blocked if the dest ip is >35.x.x.x

Does anyone have a clue why this would be happening ? Are the ISP people complete raving lunatics ? (Wouldn't surprise me). Here are some tracerts :

Tracing route to 12.1.1.1 over a maximum of 30 hops

1 10 ms 12 ms 15 ms 10.42.0.1
2 16 ms 12 ms 16 ms 196.40.3.33
3 11 ms 11 ms 11 ms sj-core01-pch10-amnet.racsa.co.cr [200.122.150.29]
4 14 ms 10 ms 12 ms sj-border01-ge3-3.racsa.co.cr [200.122.150.6]
5 57 ms 59 ms 58 ms sl-gw8-orl-5-2.sprintlink.net [144.232.145.85]
6 59 ms 58 ms 56 ms sl-bb21-orl-0-0.sprintlink.net [144.232.2.233]
7 89 ms 85 ms 88 ms sl-bb23-fw-6-0-0.sprintlink.net [144.232.8.124]
8 89 ms 88 ms 89 ms 144.232.8.14
9 107 ms 104 ms 104 ms tbr2-p012001.dlstx.ip.att.net [12.123.16.30]
10 107 ms 105 ms 108 ms tbr1-cl6.sl9mo.ip.att.net [12.122.10.89]

Tracing route to 144.1.1.1 over a maximum of 30 hops

1 11 ms 11 ms 9 ms 10.42.0.1
2 18 ms 10 ms 14 ms 196.40.3.33
3 13 ms 10 ms 13 ms sj-core01-pch10-amnet.racsa.co.cr [200.122.150.29]
4 * * * Request timed out.
5 * * * Request timed out.

Tracing route to c-24-1-1-1.hsd1.il.comcast.net [24.1.1.1]
over a maximum of 30 hops:

1 11 ms 14 ms 9 ms 10.42.0.1
2 32 ms 15 ms 12 ms 196.40.3.33
3 11 ms 12 ms 11 ms sj-core01-pch10-amnet.racsa.co.cr [200.122.150.29]
4 13 ms 13 ms 40 ms sj-border01-ge3-3.racsa.co.cr [200.122.150.6]
5 57 ms 59 ms 76 ms sl-gw8-orl-5-2.sprintlink.net [144.232.145.85]
6 59 ms 59 ms 56 ms sl-bb20-orl-0-0.sprintlink.net [144.232.2.232]
7 71 ms 69 ms 68 ms sl-bb21-atl-2-0.sprintlink.net [144.232.20.106]
8 71 ms 74 ms 72 ms sl-bb22-atl-15-0.sprintlink.net [144.232.12.150]
9 91 ms 88 ms 85 ms sl-bb23-fw-13-0.sprintlink.net [144.232.8.67]
10 88 ms 88 ms 88 ms 144.232.8.14

Tracing route to 37.1.1.1 over a maximum of 30 hops

1 10 ms 14 ms 9 ms 10.42.0.1
2 12 ms 15 ms 15 ms 196.40.3.33
3 18 ms 14 ms 16 ms sj-core01-pch10-amnet.racsa.co.cr [200.122.150.29]
4 * * * Request timed out.
5 * * * Request timed out.

Tracing route to 35.255.255.255 over a maximum of 30 hops

1 14 ms 10 ms 11 ms 10.42.0.1
2 14 ms 14 ms 18 ms 196.40.3.33
3 15 ms 32 ms 13 ms sj-core01-pch10-amnet.racsa.co.cr [200.122.150.29]
4 12 ms 17 ms 13 ms sj-border01-ge3-3.racsa.co.cr [200.122.150.6]
5 57 ms 55 ms 56 ms sl-gw8-orl-5-2.sprintlink.net [144.232.145.85]
6 58 ms 58 ms 56 ms sl-bb20-orl-0-0.sprintlink.net [144.232.2.232]
7 67 ms 67 ms 67 ms sl-bb21-atl-2-1.sprintlink.net [144.232.20.125]
8 79 ms 96 ms 75 ms sl-bb22-atl-15-0.sprintlink.net [144.232.12.150]
9 90 ms 85 ms 87 ms sl-bb23-fw-13-0.sprintlink.net [144.232.8.67]
10 86 ms 85 ms 87 ms sl-bb22-fw-13-0.sprintlink.net [144.232.11.241]

**JamesO** · 02-22-2007, 04:22 AM

Not every device is configured to respond to Route Traces and Pings, also some devices have a limited number of Route Traces and Pings sessions it can support.

Occasional asymmetrical routing paths can cause route traces to time out as well.

If these addresses are really valid and you can ping them or contact the site, then there is really no issue here that I can see.

144.1.1.1 is assigned to Misubishi (Mitsubishi??) Heavy Industries, LTD. System Engineering Department. It appears to be a valid IP address, but unused ip address. I get the same basic results in my trace route via my ISP. This address appears to be unadvertised and unused at this time.

37.1.1.1 is a reserved block for http://www.iana.org
It appears to be a valid IP address but I get the same basic results in my trace route. This address appears to be unadvertised and unused at this time.

In both of the above cases, I get very similar route trace results to what you have. It appears the ISP is trying to route or find a path for these addresses, but finds there is no routing tables or paths to send this data forward outside of the ISP network beyond a certain point.

In the end, there is no filtering and this really is a non issue.

JamesO

robroy22 · 02-22-2007, 12:34 PM

thank you for your helpful reply.

you might notice that 35.255.255.255 or 12.1.1.1 are also just as "unadvertised" and unused as the ips that don't trace.

if you'd like to focus on the problem described, namely that any adress up to 35.255.255.255, whether existent or not, advertised or not, interesting or not traces past the isp, while no adress over 36.1.1.1, whether again existent or not, advertised or not, interesting or not, fails to trace past the isp i'd be even more grateful.

02-22-2007, 01:46 AM	#1 (permalink)
robroy22 Registered User Join Date: Feb 2007 Posts: 2 OS: xp	Strange Filtering by ISP Basically what happens is that tracert (and ping) runs just fine if the dest ip is < 36.x.x.x and seems blocked if the dest ip is >35.x.x.x Does anyone have a clue why this would be happening ? Are the ISP people complete raving lunatics ? (Wouldn't surprise me). Here are some tracerts : Tracing route to 12.1.1.1 over a maximum of 30 hops 1 10 ms 12 ms 15 ms 10.42.0.1 2 16 ms 12 ms 16 ms 196.40.3.33 3 11 ms 11 ms 11 ms sj-core01-pch10-amnet.racsa.co.cr [200.122.150.29] 4 14 ms 10 ms 12 ms sj-border01-ge3-3.racsa.co.cr [200.122.150.6] 5 57 ms 59 ms 58 ms sl-gw8-orl-5-2.sprintlink.net [144.232.145.85] 6 59 ms 58 ms 56 ms sl-bb21-orl-0-0.sprintlink.net [144.232.2.233] 7 89 ms 85 ms 88 ms sl-bb23-fw-6-0-0.sprintlink.net [144.232.8.124] 8 89 ms 88 ms 89 ms 144.232.8.14 9 107 ms 104 ms 104 ms tbr2-p012001.dlstx.ip.att.net [12.123.16.30] 10 107 ms 105 ms 108 ms tbr1-cl6.sl9mo.ip.att.net [12.122.10.89] Tracing route to 144.1.1.1 over a maximum of 30 hops 1 11 ms 11 ms 9 ms 10.42.0.1 2 18 ms 10 ms 14 ms 196.40.3.33 3 13 ms 10 ms 13 ms sj-core01-pch10-amnet.racsa.co.cr [200.122.150.29] 4 * * * Request timed out. 5 * * * Request timed out. Tracing route to c-24-1-1-1.hsd1.il.comcast.net [24.1.1.1] over a maximum of 30 hops: 1 11 ms 14 ms 9 ms 10.42.0.1 2 32 ms 15 ms 12 ms 196.40.3.33 3 11 ms 12 ms 11 ms sj-core01-pch10-amnet.racsa.co.cr [200.122.150.29] 4 13 ms 13 ms 40 ms sj-border01-ge3-3.racsa.co.cr [200.122.150.6] 5 57 ms 59 ms 76 ms sl-gw8-orl-5-2.sprintlink.net [144.232.145.85] 6 59 ms 59 ms 56 ms sl-bb20-orl-0-0.sprintlink.net [144.232.2.232] 7 71 ms 69 ms 68 ms sl-bb21-atl-2-0.sprintlink.net [144.232.20.106] 8 71 ms 74 ms 72 ms sl-bb22-atl-15-0.sprintlink.net [144.232.12.150] 9 91 ms 88 ms 85 ms sl-bb23-fw-13-0.sprintlink.net [144.232.8.67] 10 88 ms 88 ms 88 ms 144.232.8.14 Tracing route to 37.1.1.1 over a maximum of 30 hops 1 10 ms 14 ms 9 ms 10.42.0.1 2 12 ms 15 ms 15 ms 196.40.3.33 3 18 ms 14 ms 16 ms sj-core01-pch10-amnet.racsa.co.cr [200.122.150.29] 4 * * * Request timed out. 5 * * * Request timed out. Tracing route to 35.255.255.255 over a maximum of 30 hops 1 14 ms 10 ms 11 ms 10.42.0.1 2 14 ms 14 ms 18 ms 196.40.3.33 3 15 ms 32 ms 13 ms sj-core01-pch10-amnet.racsa.co.cr [200.122.150.29] 4 12 ms 17 ms 13 ms sj-border01-ge3-3.racsa.co.cr [200.122.150.6] 5 57 ms 55 ms 56 ms sl-gw8-orl-5-2.sprintlink.net [144.232.145.85] 6 58 ms 58 ms 56 ms sl-bb20-orl-0-0.sprintlink.net [144.232.2.232] 7 67 ms 67 ms 67 ms sl-bb21-atl-2-1.sprintlink.net [144.232.20.125] 8 79 ms 96 ms 75 ms sl-bb22-atl-15-0.sprintlink.net [144.232.12.150] 9 90 ms 85 ms 87 ms sl-bb23-fw-13-0.sprintlink.net [144.232.8.67] 10 86 ms 85 ms 87 ms sl-bb22-fw-13-0.sprintlink.net [144.232.11.241]

02-22-2007, 04:22 AM	#2 (permalink)
JamesO Join Date: Mar 2005 Location: Fairfax, VA USA Posts: 2,289 OS: 98SE, W2k Pro, XP Pro	Not every device is configured to respond to Route Traces and Pings, also some devices have a limited number of Route Traces and Pings sessions it can support. Occasional asymmetrical routing paths can cause route traces to time out as well. If these addresses are really valid and you can ping them or contact the site, then there is really no issue here that I can see. 144.1.1.1 is assigned to Misubishi (Mitsubishi??) Heavy Industries, LTD. System Engineering Department. It appears to be a valid IP address, but unused ip address. I get the same basic results in my trace route via my ISP. This address appears to be unadvertised and unused at this time. 37.1.1.1 is a reserved block for http://www.iana.org It appears to be a valid IP address but I get the same basic results in my trace route. This address appears to be unadvertised and unused at this time. In both of the above cases, I get very similar route trace results to what you have. It appears the ISP is trying to route or find a path for these addresses, but finds there is no routing tables or paths to send this data forward outside of the ISP network beyond a certain point. In the end, there is no filtering and this really is a non issue. JamesO

02-22-2007, 12:34 PM	#3 (permalink)
robroy22 Registered User Join Date: Feb 2007 Posts: 2 OS: xp	thank you for your helpful reply. you might notice that 35.255.255.255 or 12.1.1.1 are also just as "unadvertised" and unused as the ips that don't trace. if you'd like to focus on the problem described, namely that any adress up to 35.255.255.255, whether existent or not, advertised or not, interesting or not traces past the isp, while no adress over 36.1.1.1, whether again existent or not, advertised or not, interesting or not, fails to trace past the isp i'd be even more grateful.