This fix is from work in progress by the Quagga community Solaris maintainer.
It does not have a specific bug but will eventually be incorporated in the
main branch.

*** lib/if.c
--- lib/if.c
*************** if_is_running (struct interface *ifp)
*** 341,346 ****
--- 341,361 ----
  int
  if_is_operative (struct interface *ifp)
  {
+ #ifdef SUNOS_5
+   /* Administrators on Solaris can set IFF_NORTEXCH on interfaces to
+    * indicate they should not be touched by routing protocols.  This can be
+    * configured with, e.g.
+    *
+    *   ipadm set-ifprop -p exchange_route=off 
+    *
+    * Honour this by simply considering IFF_NORTEXCH interfaces as
+    * inoperative for general purposes of Quagga code.  zebra will withdraw
+    * interface/addresses that go IFF_NORTEXCH from Quagga clients.
+    */
+   if (ifp->flags & IFF_NORTEXCH)
+     return 0;
+ #endif /* SUNOS_5 */
+ 
    return ((ifp->flags & IFF_UP) &&
  	  (ifp->flags & IFF_RUNNING || !CHECK_FLAG(ifp->status, ZEBRA_INTERFACE_LINKDETECTION)));
  }