# [SOLVED] Router can't reach some destinations.

## meal

Topic not  related to gentoo, but really fills in this category.

My problem is, after upgrading my WAN "interface" from USB modem Thomson Speedtouch 330 to adsl router Speedtouch ST06, reaching some sites. For example: forums.gentoo.org (no I'm running on socks proxy on my external server). While icmp packets reaching destination, that tcp can't. I diagnosed that with tcptraceroute and "normal" traceroute too. Trace to destination host exceeds 30 hops (wtf?) , when previously it was only 21-22 max. 

I have no idea how to solve this problem, because web interface of this router is so simply, so I can't find any proper options. I've also have access to CLI, but it sucks so much....

Any ideas what it might be?

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## think4urs11

wild guess: check MTU settings

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## meal

It was what I've checked first. It's 1500 and I think that is proper value for ATM device (PPPoA exactly).

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## papahuhn

Try with 1462.

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## meal

Hi,

thank you for solution, I've tried to change MTU for device on which problem exists and still doesn't work..

here is my traceroute to forums.gentoo.org:

```
meal@oziris ~ $ traceroute forums.gentoo.org

traceroute to forums.gentoo.org (140.211.166.170), 30 hops max, 60 byte packets

 1  192.168.0.254 (192.168.0.254)  63.250 ms  62.673 ms  62.294 ms

 2  kat-ru1.neo.tpnet.pl (213.25.2.205)  20.069 ms  22.601 ms  24.415 ms

 3  ge-1-1-0.kat-r2.tpnet.pl (213.25.5.185)  27.318 ms  29.709 ms  32.390 ms

 4  xe-6-1-1-0.ffttr2.Frankfurt.opentransit.net (193.251.255.249)  65.392 ms  67.232 ms  70.363 ms

 5  xe-4-2-0.edge3.frankfurt1.level3.net (4.68.127.197)  75.284 ms  77.699 ms xe-8-3-0.edge3.frankfurt1.level3.net (4.68.111.233)  80.668 ms

 6  vlan79.csw2.Frankfurt1.Level3.net (4.68.23.126)  92.737 ms vlan89.csw3.Frankfurt1.Level3.net (4.68.23.190)  66.140 ms vlan79.csw2.Frankfurt1.Level3.net (4.68.23.126)  71.207 ms

 7  ae-62-62.ebr2.Frankfurt1.Level3.net (4.69.140.17)  66.406 ms ae-72-72.ebr2.Frankfurt1.Level3.net (4.69.140.21)  67.938 ms  67.031 ms

 8  ae-44-44.ebr2.Washington1.Level3.net (4.69.137.62)  174.011 ms  152.419 ms ae-43-43.ebr2.Washington1.Level3.net (4.69.137.58)  152.882 ms

 9  ae-2-2.ebr2.Chicago2.Level3.net (4.69.132.69)  151.758 ms  156.336 ms  158.211 ms

10  ae-1-100.ebr1.Chicago2.Level3.net (4.69.132.113)  162.769 ms  168.074 ms  170.774 ms

11  ae-3.ebr2.Denver1.Level3.net (4.69.132.61)  205.821 ms  206.501 ms  207.172 ms

12   (4.69.132.53)  248.617 ms  249.308 ms  249.975 ms

13   (4.68.105.39)  251.984 ms  213.330 ms  216.297 ms

14  UNIVERSITY.edge5.Seattle1.Level3.net (63.211.200.246)  225.532 ms  229.214 ms  222.472 ms

15  corv-car1-gw.nero.net (207.98.64.177)  227.896 ms  233.534 ms  235.484 ms

16  * * *

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meal@oziris ~ $ 

```

and tcptraceroute result to this same host:

```

 tcptraceroute forums.gentoo.org

Selected device eth0, address 192.168.0.3, port 45684 for outgoing packets

Tracing the path to forums.gentoo.org (140.211.166.170) on TCP port 80 (http), 30 hops max

 1  192.168.0.1  0.322 ms  0.235 ms  0.258 ms

 2  192.168.0.254  42.854 ms  99.818 ms

    kat-ru1.neo.tpnet.pl (213.25.2.205)  14.920 ms

 3  ge-1-1-0.kat-r2.tpnet.pl (213.25.5.185)  25.065 ms  14.527 ms  12.876 ms

 4  xe-6-1-1-0.ffttr2.Frankfurt.opentransit.net (193.251.255.249)  43.326 ms  43.451 ms  143.588 ms

 5  xe-4-2-0.edge3.frankfurt1.level3.net (4.68.127.197)  46.413 ms

    xe-8-3-0.edge3.frankfurt1.level3.net (4.68.111.233)  45.990 ms  46.017 ms

 6  vlan79.csw2.Frankfurt1.Level3.net (4.68.23.126)  46.574 ms  77.565 ms

    vlan89.csw3.Frankfurt1.Level3.net (4.68.23.190)  115.383 ms

 7  ae-82-82.ebr2.Frankfurt1.Level3.net (4.69.140.25)  45.686 ms  47.044 ms  46.225 ms

 8  ae-44-44.ebr2.Washington1.Level3.net (4.69.137.62)  153.931 ms  152.356 ms  152.598 ms

 9  ae-2-2.ebr2.Chicago2.Level3.net (4.69.132.69)  153.252 ms  150.425 ms  150.894 ms

10  ae-1-100.ebr1.Chicago2.Level3.net (4.69.132.113)  152.512 ms  151.111 ms  152.476 ms

11  ae-3.ebr2.Denver1.Level3.net (4.69.132.61)  182.780 ms  185.216 ms  196.963 ms

12  ae-2.ebr2.Seattle1.Level3.net (4.69.132.53)  215.814 ms  224.837 ms  210.882 ms

13  ge-11-0.hsa2.Seattle1.Level3.net (4.68.105.39)  211.733 ms  218.396 ms  219.373 ms

14  UNIVERSITY.edge5.Seattle1.Level3.net (63.211.200.246)  215.535 ms  214.878 ms  215.113 ms

15  corv-car1-gw.nero.net (207.98.64.177)  217.334 ms  218.659 ms  217.872 ms

16  * * *

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30  * * *

Destination not reached

```

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## eccerr0r

It's possible the machines past that have some ICMP filtered.

I can't traceroute to forums.gentoo.org either, and stops at the same place your trace stops at.

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## krinn

i don't have a solve for you, but you should check that:

 *Quote:*   

> 1  192.168.0.254 (192.168.0.254)  63.250 ms  62.673 ms  62.294 ms 

 

 *Quote:*   

> 2  192.168.0.254  42.854 ms  99.818 ms 

 

That's a shitty answer for a router, 

here's mine 

```
1  192.168.0.100  7.149 ms  7.985 ms  8.701 ms
```

and it looks more what you may expect from a device that is plug near your network card.

and look the 2. that ip respond faster than your own router  :Razz: 

```

1  192.168.0.254 (192.168.0.254)  63.250 ms  62.673 ms  62.294 ms

2  kat-ru1.neo.tpnet.pl (213.25.2.205)  20.069 ms  22.601 ms  24.415 ms 
```

You should dig that (even it have nothing to do with gentoo forum not answering, it might have to do with long delays and/or hardware failure)

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## ScarletPimpFromHell

You will probably have to use the TCP "set Maximum Segment Size" IP option. 

In Australia the MTU size of a PPPoA circuit is 1492 bytes, thats 1500 minus the 8 byte PPP header & trailer.

So if you are using PPPoA then deduct another 20 bytes for the IP header and then another 20 bytes for the TCP header. That leaves you with a 1452 byte payload. 

I don't know how to set the MSS option on a speedtouch, but you should be looking at around a figure of 1452 bytes.

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## meal

Hi guys,

Thank you all for help and advices. I've solved the problem, but the way which I did it a little bit weird. What I did, is restore configuration to default, and configure device once again from zero. Now I have many work with port forwarding (I've got server behind this router, and need almost 50 ports forwarded) but everything works fine. Now I'm writing this post without any proxies between me and forums.gentoo.org server..

Happy Meal   :Laughing: 

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