Currently the mempool isn't persisted across restarts. The historical argument against doing this is that it would make transactions immortal. Expiration now addresses that issue.

Without preserving the mempool node behavior changes drastically across restarts which complicates production use (e.g. mining overly small/low fee blocks) as well as development testing. The lack of retention also causes the loss of txn priority modifications made with prioritisetransaction which makes the API less reliable.

CService addrBind;
                if (!Lookup(strBind.c_str(), addrBind, 0, false))
                    return InitError(ResolveErrMsg("whitebind", strBind));
                if (addrBind.GetPort() == 0)
                    return InitError(strprintf(_("Need to specify a port with -whitebind: '%s'"), strBind));
                fBound |= Bind(connman, addrBind, (BF_EXPLICIT | BF_REPORT_ERROR | BF_WHITELIST));
            }
        }
        else {
            struct in_addr inaddr_any;
            inaddr_any.s_addr = INADDR_ANY;
            fBound |= Bind(connman, CService(in6addr_any, GetListenPort()), BF_NONE);
            fBound |= Bind(connman, CService(inaddr_any, GetListenPort()), !fBound ? BF_REPORT_ERROR : BF_NONE);
        }
        if (!fBound)
            return InitError(_("Failed to listen on any port. Use -listen=0 if you want this."));
    }
    if (mapArgs.count("-externalip")) {
        BOOST_FOREACH(const std::string& strAddr, mapMultiArgs["-externalip"]) {
            CService addrLocal;
            if (Lookup(strAddr.c_str(), addrLocal, GetListenPort(), fNameLookup) && addrLocal.IsValid())
                AddLocal(addrLocal, LOCAL_MANUAL);
            else
                return InitError(ResolveErrMsg("externalip", strAddr));
        }
    }
    BOOST_FOREACH(const std::string& strDest, mapMultiArgs["-seednode"])