routing problem to West US?

plodder

I can't access any sites on West coast of US. UK + Ireland is fine. Also East coast of US. But sites like facebook, microsoft just hang. DNS is fine. Problem just connection hangs, packets are disappearing into the ether.

If I connect to my employers VPN then everything works fine, which suggests an Eircom routing problem. I am located in North (West) county Dublin.

java

I'm on eircom and can access those sites fine. If there was a widespread problem there would be more public complaints. Suggest you paste a traceroute to sample problem sites so reps can assist you.

plodder

Right. I'm sure it's not a widespread problem. Here is a traceroute:

$ traceroute www.facebook.com
traceroute to www.facebook.com (173.252.101.26), 30 hops max, 60 byte packets

[edit] Actually I notice now that tfbnw.net is inside facebook. So, that's not an Eircom problem. [edit2] Actually, it seems facebook is accessible after all. It only seems to be sites that are accessed through "tinet.net".

Here's a traceroute to cisco

$ traceroute www.cisco.com
traceroute to www.cisco.com (2.18.144.170), 30 hops max, 60 byte packets
1 192.168.1.254 (192.168.1.254) 8.919 ms 18.493 ms 18.509 ms
2 b-ras1.blp.dublin.eircom.net (159.134.155.20) 58.145 ms 90.052 ms 99.856 ms
3 ge-6-1-8.pe1.blp.blp-srl.eircom.net (86.43.246.53) 116.966 ms 119.743 ms 129.707 ms
4 tenge-6-1-1.core2.srl.core.eircom.net (86.43.253.137) 139.927 ms 149.716 ms 158.701 ms
5 tenge-3-2-1.core2.dbn.core.eircom.net (86.43.252.41) 169.604 ms 178.764 ms 188.578 ms
6 tenge-1-2-1.pe2.6cr.6cr-6cr.eircom.net (86.43.255.98) 199.603 ms 65.220 ms 60.627 ms
7 ge4-0-0.peering1.tcy.dublin.eircom.net (86.43.244.133) 70.155 ms 81.423 ms 89.759 ms
8 ge-1-1-0.dub20.ip4.tinet.net (77.67.64.161) 111.347 ms 121.137 ms 130.249 ms
9 so-10-0-0.dub40.ip4.tinet.net (89.149.187.1) 140.144 ms 150.125 ms so-10-1-0.dub40.ip4.tinet.net (89.149.186.193) 169.512 ms
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plodder

More information. It appears I can telnet to port 80 on each of these sites. So, while firefox can't connect and traceroute seems to get confused too, it sounds like it isn't an Eircom problem. Apologies!!

eircom: Mark

plodder wrote: »

More information. It appears I can telnet to port 80 on each of these sites. So, while firefox can't connect and traceroute seems to get confused too, it sounds like it isn't an Eircom problem. Apologies!!

Hi plodder,

I sent on the thread to managers in broadband support, they have not had any similar issues logged.

Thanks for posting the update on the thread.

Mark

plodder

Update on this. Looks like the problem was the MTU setting on my laptop (and possibly other computers on the network here) Apparently, some servers don't do a good job of reassembling packets split by a too high MTU.  So, why is the auto MTU discovery not working? Got a new router Eircom router last week. Maybe some setting on that has caused it. Anyway, reducing the MTU from 1500 to 1492 fixed it.

[edit]Just to be clear, the problem wasn't the MTU setting on the laptop. Changing it was a work-around. The problem must have been some setting on the new router, or something that changed in the Eircom network.