Irish Broadband MTU Issues RESOLVED - Business User

Simon_Scott

For some time (6-12 months) I have been experiencing problems with internet connection from 4 seperate companies all using Irish Broadband. These problems were accessing certain websites, file download failures and email problems. After extensive research I added an MTU entry into the registry of all PCs and servers behind the firewall (Checkpoint NG R55) and assigned the decimal value 1400. This resolved the problem on our primary connection but gave problems on our redundant connection - not a great problem as this was only used if the primary connection was down.
Today I have allowed two ICMP Services through the firewall, removed the MTU entry and am experiencing no problems. The Services are:
ICMP Type 3 Code 3
ICMP Type 3 Code 4
Checkpoint versions later than NG FP1 are supposed to transparently match ICMP control messages with established connections but it isn't reliable.
This is not just a problem with Checkpoint firewalls.
Hope this helps anyone else who is having a similar problem

Sponge Bob

MTU Path Discovery !

philologos

Irish Broadband decent again?

spooky donkey

I doubt it. I have no idea what this guy is talking about and its not going to help me.

BrendanD

Sponge Bob wrote:

MTU Path Discovery !

dub45

spooky donkey wrote:

I doubt it. I have no idea what this guy is talking about and its not going to help me.

Thought it was just me!

The universal tranlator is broken again Captain;)

Sponge Bob

He has a sophisticated firewall , he let certain ICMP services IN thru the firewall. Good **** happened and kittens were saved.

BrendanD

Have to say i love the title of the thread, just got my hopes up for all of 3 seconds.

spooky donkey

It does give hope and amid all the negitive IBB threads ya wonder where this is comming from given they guy has just signed today to make this thread and has only 1 post.

Sponge Bob

what hope, their own techs know nothing about this !

Simon_Scott

Sorry to raise your hopes with the Title which I have now changed. The post is coming from a business user responsible for 4 sites who has attempted to resolve a connection issue for the past 12 months. I have started to look at other providers with a view to moving if this problem occurrs again.

MrPudding

I had a similar problem with ADSL. I could not access Yahoo mail and a few other sites that needed authentication. I do not think this problem is nessecarily unique to IBB.

I had ADSL with no issue. I then purchased a Linksys WRT54G. Once I had it installed I was unable to access said sites. Quick google and I found the fix, change the MTU setting on the router. Job done.

So you can add UTV internet to IPS's that carry customers that can have this issue.

MrP

sisyphus

Not really the same issue as above, but my brother was having major issues with VoIP using his LinkSys over the IBB 2 Mbps line off the Guinness high-site. He had no problems with it if he connected directly, but once he went through his router, the VoIP quality went to ****e. After a lot of playing around and much noodle scratching, he also found that changing his router's MTU settings greatly improved the quality of VoIP. Now, I can't remember if he increased or decreased the MTU levels (Which admittedly doesn't give others who are having similar issues much information), but it may be worth experimenting around with this if you're also having problems.....
My two cents......!

ro2

TCP Optimizer is a handy tool to find your ideal MTU:

http://www.speedguide.net/downloads.php

Sparky

had same crap on Metro till it was resolved quite quick, by our main man crawler.
:v: