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Routing issue?

Hi guys,

Got a bizarre one.

Got a client with 8 sites. They all VPN to each other linking them together.
The other week, the client told me that computers on the network couldn't go to some websites. Basically all computers could only go to google, they could search google, but once they click on a result, it doesn't navigate at all. I thought it was malware straight up so I started looking at the hosts file, proxy settings, IP settings and ran a few antimalware scans - all came back clean. The client told me they rebooted the router but I thought I'd try it from my end (via the interface)...Rebooted and all worked fine.

This week I've had 3 calls from 3 of the sites saying that they all got the exact same problem...I've logged in remotely and I confirm this. They can all browse google but nothing further. I noticed one of the physical sites allowed me to get in to 1 or 2 results here and there, but the majority failed either giving a blank white screen as if its trying to load, or just sitting at the search results. I also tried another browser and my personal laptop - same problem.

The only thing I can think of is that the routers are stuffed - It's just incredible that 3 have gone within 4-5 days of each other. They are Cisco RV042 routers and they have been in use for around 3-4 years.

So yesterday, I took one of the problematic sites out of the VPN loop (as it wasn't required anymore) and took the modem out of bridge mode and had it act as modem/router. All worked perfectly straight away.

I'm probably answering my own question here...I'm just gobbed smacked that this has all happened at once plus the client probably thinks it's got something to do with me putting in a new SBS server for them.

Can anyone think of anything else that I haven't covered? Thanks
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Talds_Alouds
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Talds_Alouds
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1 Solution
 
NiceCuppaTeaCommented:
DNS server correctly configured on SBS? Forwarders setup for non resolvable addresses? Is your SBS server also the DHCP server or has it decided it want to be the DHCP server instead of your ciscos?
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apreedCommented:
Agree with NiceCuppaTea. Sounds like a DNS issue. What are your clients configured to use to resolve DNS? If they use the router, how is the router configured to resolve DNS? (Hopefully via your internal DNS servers)
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Talds_AloudsAuthor Commented:
Ok so SBS is dhcp.
Dns forwarders correct. Only 1 site has SBS, the other sites just have router as dns. Note that all external hostnames can be pinged and they resolve, just no web action therefore I don't think it's Dns.
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NiceCuppaTeaCommented:
Do you have static routes on all of the routers for 0.0.0.0?
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Talds_AloudsAuthor Commented:
Nope.
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Talds_AloudsAuthor Commented:
Ok I think I've fixed it. Seems to be an issue with the MTU. They were all set on auto and have been working fine for the last 4-5 years. I had only just been alerted not that long ago that almost all the stores were experiencing this problem.

Anyone know what would cause this? my ISP is Telstra Business Broadband ADSL2+ (in Australia).
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Talds_AloudsAuthor Commented:
Fixed myself.
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