proper settings for connecting RB532 to dsl ?????

RouterOS General
1

I have the problem described in other posts where some of the pages load and others don’t. I also seen where they mention changing the MTU. I looked at the settings in the modem and it has 1540 for MTU. My question is how do we know what to put on the RB to make it work because the RB won’t even except a setting of 1540. Also is this the only other setting that I need to worry about because I already have the PPPoE client part working.

Packet Information

VPI / VCI
In Errors
In Discard Packets
In Non Unicast Packets
In Unicast Packets
In Octets

Out Errors
Out Discard Packets
Out Non Unicast Packets
Out Unicast Packets
Out Octets

MTU
Interface Type
Interface Description
PVC 1

0 / 35
0
0
0
1156820
285881225

0
0
117722
1192801
160718267

1540
1
MAC BRIDGE CONNECTION

2

Does anyone have a suggestion?

3

I use either 1460-1476 for the MTU settings depending on the type of connection and so on. Most of the time you will be safe with 1460.

Matt

RB133 limited web but can ssh
4

do you change this setting in winbox under interfaces and then under pppoe interface or do you put a rule under mangle.

since my dsl modem has a setting of 1540 and 20 percent is is what they recommend knocking off then 1232 would be correct. to be honest I have never had to change mtu or use a mangle rule before so this is all new to me.
thanks

5

There are tons of ways to do the MTU setting. Mangle is one way.

Matt

6

20%??? I think you must mean 20 bytes…

7

if 20 bytes less is what I need to set it at then 1520 would be the correct number and if so i’ve got a problem because the dsl modem is 1540

what should I do?

i’ve tried setting it at 1500,1490,1480,1460 and 1320. everyone of the settings had the same problem, it would’nt load most of the pages I tried.

more help please!

8

I just talked with verizon and they are going to send me a new modem to try since the mtu shows 1540. They think something is wrong because of this. I will update on the 22nd. Thanks all for your help.

9

Sure would be nice if the Mikrotiks would do this automatically like every other router out there.

http://forum.mikrotik.com/t/mtu-problems/12811/18

This works in my office but not at the customers site so I am stuck buying a linksys or someother such router instead of using the Mikrotik like I wanted.

10

Thanks MENUMARK for these rules and JOIE for the link to them. Worked like a charm!

Try the following rules…

/ ip firewall mangle
add chain=forward tcp-flags=syn action=jump jump-target=mss comment=“[tcp], mss” disabled=no
add chain=mss protocol=tcp tcp-flags=syn tcp-mss=!536-1460 action=change-mss new-mss=1440 comment=“[tcp], mss fixation” disabled=no
add chain=mss protocol=tcp tcp-flags=syn tcp-mss=1453-65535 action=change-mss new-mss=1440 comment=“[tcp], mss 1440 for mtu 1492” disabled=no
add chain=mss protocol=tcp tcp-flags=syn action=change-mss new-mss=clamp-to-pmtu comment=“[tcp], mss clamp-to-pmtu” disabled=no
add chain=prerouting action=change-ttl new-ttl=set:65 comment=“[tcp], mss ttl fix” disabled=no

By the way the new router showed the same settings and wouldn’t work without these rules either. Thanks Again