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codoherty

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Host internet web server using multiple ADSL line

Is it possible to service a internet web server using multiple ADSL line.
I understand a domain is resolved to 1 public IP which resolves to 1 ADSL line.
But can the requests come on 1 ADSL (static IP) but replied on many ADSL.
Or is there an alternative?
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giltjr
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You could setup your DNS server to do round robin address resolution.  Have on A record that resloves to multiple IP addresses.  However this does not help if one of the ADSL connections goes out of service.

Generally this is done with mutliple dedicated circuts (Frac. T1/E1, Full T1/E1, Frac. T3/E3, Full T3/E3 and so on).
hi there

u can host a internet webserver using multiple adsl lines but incase the adsl link for the StaticIP is lost in such a case all the web sites hosted with that public IP will not be reachable so its better that u should have a consistent connection for the StaticIP.

coming to the other part of resolving 1 public IP u can have multiple public IPs for a single domain getting resolved.
 i.e say u have two public IPs if one of the connection with public IP is down the name resolution can happen on the second public IP

bhanu
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codoherty

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Thanks for your replies.

Ok! lets recap.

I can have multiple adsl lines (each with a static IP) with multiple DNS enteries. If one of the adsl lines on down the FQDN will resolve to the another DNS A card (IP). The round robin solution requires software on the DNS (I guess?), and if one of the adsl lines is down the round robiin will use another a card. Is this correct?

Regards,
Conor
No, sort of.  Most DNS server software support round robin today with out any upgrades.  Say you define a A record with three IP addresses.  The general id is that the first query that the DNS server gets it will respond with address 1, the next query it will respond with 2, the next 3, and the next 1 again.

If a ADSL router with address 2 fails, the DNS server will STILL respond with address 2 one out of every 3 queries. So one out of every 3 queries will attempt to connect to the IP address on the failed ADSL router.
Can a request come in on 1 adsl (static IP) and the response serviced on another adsl or does the response have to go out on the same route it came in, or does this depend on server side software.
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giltjr
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Cheers guiltjr,

I'm new to EE and even though you comfirmed what I believed was true your patience and clarity is unprecedented. I hope I can help you and others within my arena of expertise in the future.
Thanks and welcome to EE.  There are a lot of great people here that are always more than willing to help and we are alway glad to have other experts join.