NAT whit TTL=1

Unanswered Question
Apr 12th, 2007

My ISP give me a real IP, but restrict whit TTL=1 and i want NAT to my network 10.10.10.0/28. My router is 1811.

and Ihave vlan1 on 10.10.10.0

FOR NAT I use this:

Router(config)#interface FastEthernet0

Router(config-if)#ip nat outside

Router(config)#interface Vlan1

Router(config-if)#ip nat inside

Router(config)#ip nat inside source list 15 interface FastEthernet0 overload

Router(config)#access-list 15 permit 10.10.10.0 0.0.0.7

But I don't have internet

I thing this is from my ISP whit TTL=1

Help

I have this problem too.
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rico_hao40 Fri, 04/13/2007 - 06:27

I do not understand why and how they restrict whit TTL=1 ? If it is, the next hop router (should be ISP router) will reduce TTL=0 and the packet will be dropped!

You can traceroute from inside PC to verify. if the packet can reach ISP router and dropped, so it is ISP' problems, call them to complain!

good luck

vaba Fri, 04/13/2007 - 11:41

this not help me. My ping to ISP from WinXP2 is:

C:\Documents and Settings\Administrator>ping x.y.z.1

Pinging x.y.z.1 with 32 bytes of data:

Reply from x.y.z.1: bytes=32 time=1ms TTL=1

Reply from x.y.z.1: bytes=32 time<1ms TTL=1

Reply from x.y.z.1: bytes=32 time=2ms TTL=1

Reply from x.y.z.1: bytes=32 time=1ms TTL=1

where x.y.z.1 is my ISP Default Gateway, but

when i ping 127.0.0.1(x.y.z.100)- is my ip addres- then TTL=128

I try install Cisco router 1811 whit NAT outside addres x.z.z.100/24 and inside addres 10.10.10.0/28, but no heve internet :((

rico_hao40 Fri, 04/13/2007 - 12:06

Please try

tracert -d 4.2.2.2

on your winxp PC and paste the result

vaba Fri, 04/13/2007 - 12:13

C:\Documents and Settings\Administrator>tracert -d 4.2.2.2

Tracing route to 4.2.2.2 over a maximum of 30 hops

1 2 ms 1 ms <1 ms x.y.z.1

2 3 ms 1 ms 2 ms 89.190.221.209

3 * * * Request timed out.

4 37 ms 38 ms 37 ms 212.162.4.13

5 42 ms 42 ms 42 ms 4.68.118.65

6 124 ms 131 ms 124 ms 64.159.1.85

7 136 ms 131 ms 137 ms 4.68.97.40

8 125 ms 126 ms 124 ms 4.2.2.2

Trace complete.

This is result from my WinXp whit real IP give from ISP

rico_hao40 Fri, 04/13/2007 - 12:18

That good! I think you already have your internet up and running !!!

probably you need to confirm your DNS is working . I guess that the reason you think your internet not work! also check your ACL.

try

#show log

Good luck

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