GSS stickiness or DNS issue

Unanswered Question
Jun 14th, 2007

GSS stickiness issue:


Customer has 4 GSS (2 in each of two sites), SSL terminatin is configured on the downlaying CSS's.

Stickiness is configured on GSS's (25 min) to force clients to go to the same site/server during transaction.

GSS are configured with two answers per answers group/ per rule.

Stickiness mask is 32 bits, so each DNS server gets its own stickiness record.

TTL for specific answer group is 30 sec - to let GSS's enough time to propagate sticky info among members.


For specific ISP DNS server I can see specific answer that GSS sticks with, and due to traffic it

looks like it stays for weeks, no flip flops.

Different ISP DNS servers have different answers (due to /32 mask).


Apparently some clients with MAC Safari browsers are getting alternate answer during transaction what caused error.

I tracked DNS resolution from client to ISP DNS, it uses same caching ISP DNS server, which replies

with proper answer usually but suddenly may reply with alternate answer which disrupts client's transaction.

As I said sticky record for this ISP server in GSS sticy database looks solid.


Clients that have such problems use MAC with Safari dbrowser.

Safari behaves differently from IE, it looks like it obeys TTL and tries to re-resolve DNS each 30 sec

(it may be 40 - 60 sec though).



Two reasons why that may happen:

1. In that "wrong" case DNS request is coming to ISP caching DNS server and then to another DNS server

in ISP infrastructure, and that another DNS server is quering GSS and getting alternate answer as per it's own sticky record..

That was discussed with ISP and was doubted by ISP representative - any comments?


2.As four GSS's are being queried by ISP on Round Robin basis - if one (or more) GSS has inconsistent sticky record

that may cause same issue.

How I can verify that?


Thanks

Alex


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kgraft Wed, 02/25/2009 - 12:22

I have been searching the archives, as we are having this same issue with only MAC Safari users. Our GSS's have been confirmed to have their sticky databases in sync. I'm still researching on the ISP side regarding different DNS servers, but this issue is only happening with MAC users, and with different ISP's. Does anyone have any insight?


Thanks,

Kim

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