diff --git a/ais/backend/ais.go b/ais/backend/ais.go
index b78c0378d78..e13c640fc54 100644
--- a/ais/backend/ais.go
+++ b/ais/backend/ais.go
@@ -45,6 +45,7 @@ type (
 		url  string
 		uuid string
 		bp   api.BaseParams
+		bpL  api.BaseParams // long & list
 	}
 	AISbp struct {
 		t      core.TargetPut
@@ -94,6 +95,9 @@ func extractErrCode(e error, uuid string) (int, error) {
 	if e == nil {
 		return http.StatusOK, nil
 	}
+	if cos.IsClientTimeout(e) {
+		return http.StatusRequestTimeout, e
+	}
 	herr := cmn.Err2HTTPErr(e)
 	if herr == nil {
 		return http.StatusInternalServerError, e
@@ -257,7 +261,9 @@ func (r *remAis) init(alias string, confURLs []string, cfg *cmn.ClusterConfig) (
 	var (
 		url           string
 		remSmap, smap *meta.Smap
-		cliH, cliTLS  = remaisClients(&cfg.Client)
+
+		clientL      http.Client
+		cliH, cliTLS = remaisClients(&cfg.Client)
 	)
 	for _, u := range confURLs {
 		client := cliH
@@ -289,10 +295,17 @@ func (r *remAis) init(alias string, confURLs []string, cfg *cmn.ClusterConfig) (
 	r.smap, r.url = remSmap, url
 	if cos.IsHTTPS(url) {
 		r.bp = api.BaseParams{Client: cliTLS, URL: url, UA: ua}
+		clientL = *cliTLS
 	} else {
 		r.bp = api.BaseParams{Client: cliH, URL: url, UA: ua}
+		clientL = *cliH
 	}
+
+	r.bpL = r.bp
+	clientL.Timeout = cfg.Client.TimeoutLong.D()
+	r.bpL.Client = &clientL
 	r.uuid = remSmap.UUID
+
 	return
 }
 
@@ -446,7 +459,7 @@ func (m *AISbp) ListObjects(remoteBck *meta.Bck, msg *apc.LsoMsg, lst *cmn.LsoRe
 	unsetUUID(&bck)
 
 	var lstRes *cmn.LsoRes
-	if lstRes, err = api.ListObjectsPage(remAis.bp, bck, remoteMsg, api.ListArgs{}); err != nil {
+	if lstRes, err = api.ListObjectsPage(remAis.bpL, bck, remoteMsg, api.ListArgs{}); err != nil {
 		ecode, err = extractErrCode(err, remAis.uuid)
 		return
 	}
@@ -540,6 +553,7 @@ func (m *AISbp) HeadObj(_ context.Context, lom *core.LOM, _ *http.Request) (oa *
 	return
 }
 
+// TODO: retry
 func (m *AISbp) GetObj(_ context.Context, lom *core.LOM, owt cmn.OWT, _ *http.Request) (ecode int, err error) {
 	var (
 		remAis    *remAis
@@ -551,7 +565,7 @@ func (m *AISbp) GetObj(_ context.Context, lom *core.LOM, owt cmn.OWT, _ *http.Re
 		return
 	}
 	unsetUUID(&remoteBck)
-	if r, size, err = api.GetObjectReader(remAis.bp, remoteBck, lom.ObjName, nil /*api.GetArgs*/); err != nil {
+	if r, size, err = api.GetObjectReader(remAis.bpL, remoteBck, lom.ObjName, nil /*api.GetArgs*/); err != nil {
 		return extractErrCode(err, remAis.uuid)
 	}
 	params := core.AllocPutParams()
@@ -564,6 +578,9 @@ func (m *AISbp) GetObj(_ context.Context, lom *core.LOM, owt cmn.OWT, _ *http.Re
 	}
 	err = m.t.PutObject(lom, params)
 	core.FreePutParams(params)
+
+	// TODO: retry upon 'unreachable' or timeout
+
 	return extractErrCode(err, remAis.uuid)
 }
 
@@ -599,11 +616,12 @@ func (m *AISbp) GetObjReader(_ context.Context, lom *core.LOM, offset, length in
 		res.ExpCksum = oa.Cksum
 		lom.SetCksum(nil)
 	}
-	res.R, res.Size, res.Err = api.GetObjectReader(remAis.bp, remoteBck, lom.ObjName, args)
+	res.R, res.Size, res.Err = api.GetObjectReader(remAis.bpL, remoteBck, lom.ObjName, args)
 	res.ErrCode, res.Err = extractErrCode(res.Err, remAis.uuid)
 	return
 }
 
+// TODO: retry upon 'unreachable' or timeout
 func (m *AISbp) PutObj(r io.ReadCloser, lom *core.LOM, _ *http.Request) (ecode int, err error) {
 	var (
 		oah       api.ObjAttrs
@@ -617,7 +635,7 @@ func (m *AISbp) PutObj(r io.ReadCloser, lom *core.LOM, _ *http.Request) (ecode i
 	unsetUUID(&remoteBck)
 	size := lom.Lsize(true) // _special_ as it's still a workfile at this point
 	args := api.PutArgs{
-		BaseParams: remAis.bp,
+		BaseParams: remAis.bpL,
 		Bck:        remoteBck,
 		ObjName:    lom.ObjName,
 		Cksum:      lom.Checksum(),
diff --git a/api/ls.go b/api/ls.go
index ac79ea102b8..87c9f4eae03 100644
--- a/api/ls.go
+++ b/api/ls.go
@@ -5,8 +5,6 @@
 package api
 
 import (
-	"context"
-	"errors"
 	"net/http"
 	"net/url"
 	"strconv"
@@ -204,7 +202,7 @@ func lsoPage(reqParams *ReqParams) (_ *cmn.LsoRes, err error) {
 		if _, err = reqParams.DoReqAny(page); err == nil {
 			return page, nil
 		}
-		if !errors.Is(err, context.DeadlineExceeded) {
+		if !cos.IsClientTimeout(err) {
 			break
 		}
 		client := *reqParams.BaseParams.Client
diff --git a/cmn/config.go b/cmn/config.go
index 8176d445235..5ed6dc50954 100644
--- a/cmn/config.go
+++ b/cmn/config.go
@@ -880,15 +880,25 @@ func (c *LogConf) Validate() error {
 // ClientConf //
 ////////////////
 
+const (
+	minClientTimeout = time.Second
+	maxClientTimeout = 30 * time.Minute
+
+	errExpectedRange = "(expected range [1s, 30m] or zero)"
+)
+
 func (c *ClientConf) Validate() error {
-	if j := c.Timeout.D(); j < time.Second || j > 2*time.Minute {
-		return fmt.Errorf("invalid client.client_timeout=%s (expected range [1s, 2m])", j)
+	if j := c.Timeout.D(); j != 0 && (j < minClientTimeout || j > maxClientTimeout) {
+		return fmt.Errorf("invalid client_timeout=%s %s", j, errExpectedRange)
+	}
+	if j := c.TimeoutLong.D(); j != 0 && (j < minClientTimeout || j > maxClientTimeout) {
+		return fmt.Errorf("invalid client_long_timeout=%s %s", j, errExpectedRange)
 	}
-	if j := c.TimeoutLong.D(); j < 30*time.Second || j < c.Timeout.D() || j > 30*time.Minute {
-		return fmt.Errorf("invalid client.client_long_timeout=%s (expected range [30s, 30m])", j)
+	if j := c.TimeoutLong.D(); j != 0 && j < c.Timeout.D() {
+		return fmt.Errorf("client_long_timeout=%s cannot be less than client_timeout=%s", j, c.Timeout.D())
 	}
-	if j := c.ListObjTimeout.D(); j < 2*time.Second || j > 15*time.Minute {
-		return fmt.Errorf("invalid client.list_timeout=%s (expected range [2s, 15m])", j)
+	if j := c.ListObjTimeout.D(); j != 0 && (j < minClientTimeout || j > maxClientTimeout) {
+		return fmt.Errorf("invalid list_timeout=%s %s", j, errExpectedRange)
 	}
 	return nil
 }
diff --git a/cmn/cos/err.go b/cmn/cos/err.go
index a3439db8e1a..35826269f05 100644
--- a/cmn/cos/err.go
+++ b/cmn/cos/err.go
@@ -188,6 +188,10 @@ func IsErrDNSLookup(err error) bool {
 	return errors.As(err, &wrapped)
 }
 
+func IsClientTimeout(err error) bool {
+	return errors.Is(err, context.DeadlineExceeded)
+}
+
 func IsUnreachable(err error, status int) bool {
 	return IsErrConnectionRefused(err) ||
 		IsErrDNSLookup(err) ||