private void UpdateBackoffCache()
        {
            bool flag = E4eProxyRequestHandler.IsE4ePostPayloadRequest(base.ClientRequest);

            if (flag)
            {
                string serverResponseCookieValue  = this.GetServerResponseCookieValue("X-E4eBudgetType");
                string serverResponseCookieValue2 = this.GetServerResponseCookieValue("X-E4eEmailAddress");
                string serverResponseCookieValue3 = this.GetServerResponseCookieValue("X-E4eBackOffUntilUtc");
                E4eBackoffListCache.Instance.UpdateCache(serverResponseCookieValue, serverResponseCookieValue2, serverResponseCookieValue3);
            }
        }
        protected override AnchorMailbox ResolveAnchorMailbox()
        {
            if (E4eProxyRequestHandler.IsErrorPageRequest(base.ClientRequest))
            {
                return(new AnonymousAnchorMailbox(this));
            }
            if (E4eProxyRequestHandler.IsE4eInvalidStoreRequest(base.ClientRequest))
            {
                this.ThrowRedirectException(E4eProxyRequestHandler.GetErrorUrl(E4eProxyRequestHandler.E4eErrorType.InvalidStoreRequest));
            }
            bool flag = E4eProxyRequestHandler.IsE4ePostPayloadRequest(base.ClientRequest);

            this.GetSenderInfo(flag);
            string text = this.senderEmailAddress;

            if (!string.IsNullOrEmpty(text) && SmtpAddress.IsValidSmtpAddress(text))
            {
                string recipientEmailAddress = base.ClientRequest.QueryString["RecipientEmailAddress"];
                if (flag)
                {
                    if (E4eBackoffListCache.Instance.ShouldBackOff(text, recipientEmailAddress))
                    {
                        PerfCounters.HttpProxyCountersInstance.RejectedConnectionCount.Increment();
                        this.ThrowRedirectException(E4eProxyRequestHandler.GetErrorUrl(E4eProxyRequestHandler.E4eErrorType.ThrottlingRestriction));
                    }
                    else
                    {
                        PerfCounters.HttpProxyCountersInstance.AcceptedConnectionCount.Increment();
                    }
                }
                return(new SmtpWithDomainFallbackAnchorMailbox(text, this)
                {
                    UseServerCookie = true
                });
            }
            if (BEResourceRequestHandler.IsResourceRequest(base.ClientRequest.Url.LocalPath))
            {
                return(new AnonymousAnchorMailbox(this));
            }
            string text2 = string.Format("The sender's email address is not valid. Email={0}, SMTP={1}", this.senderEmailAddress, text);

            base.Logger.AppendGenericError("Invalid sender email address", text2);
            throw new HttpProxyException(HttpStatusCode.NotFound, HttpProxySubErrorCode.EndpointNotFound, text2);
        }