Suddenly unable to connect to random websites
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like submicron said: mtu
this issue is most likely always an mtu issue -
I set the mtu to 1390, and it didn't resolve the issue.
I noticed that a traceroute to each of these trouble domains ends at in about 5 hops at the upstream provider. I gave them a call, and they were able to duplicate the issue… so their engineers are looking into it.
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like i said most of the time it is an mtu issue. glad you found the problem. did you perform a tracert before changing mtu?
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Yeah, I did perform the tracert before changing the mtu, but not afterwards. If the upstream provider doesn't find a problem, then I'll try again.
Out of curiosity… if it is an MTU issue, why would it suddenly happen? These websites all worked a few days ago.
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MTU issues typically crop up suddenly due to ISP changes. I've seen these issues suddenly appear for no good reason only to find that the ISP in question did a major backbone upgrade. Glad you found your issue, however.
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Oh, I haven't found the issue yet. The ISP was able to duplicate the problem, but neither I nor they know exactly what is causing it. They haven't gotten back in touch with me yet. I may mess around with changing the MTU again today. What is an acceptable range for the MTU?
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it depends on what you are using (ethernet, wireless,jumbo frames etc) but heres a breakdown:
http://en.wikipedia.org/wiki/Maximum_transmission_unit and http://tools.ietf.org/html/rfc1191
though for most it is either 1492 or 1500 -
Well, I tried a bunch of different MTU's on the WAN interface between 1000 and 1500, but no luck. This client has SDSL 1.1/1.1.
If the MTU is set in pfSense, would it make any difference to try setting it on the DSL modem also, since the traffic is all going through the pfSense router?
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is the dsl modem doing the authentication or is pfsense? if the modem is bridged it should only have to be done in pfsense
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I talked to the upstream provider again. It looks like we discovered a system-wide outage.
It's a lot more fun when I have control over the situation!
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Sounds a lot like the expected symptoms of IPv6 'brokeness' ::)
Steve
